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line-mini-dapp

LINE's Mini Dapp & Dapp Portal

Introduction

Mini Dapps powered by Kaia Blockchain are lightweight Web3 applications that run inside LINE Messenger with Mini Dapp SDK, without requiring any separate app installation. Mini Dapps span across categories such as Games, DeFi, AI, and more, all accessible through the Dapp Portal. Within the Dapp Portal, users can easily:

Discover and access a variety of Mini Dapps
Receive rewards for playing Mini Dapp
SWAP tokens of Mini Dapp and Trade NFTs
Experience seamless Web3 interaction with Mini Dapp Wallet

Kaia Wave Program

Kaia Wave is an onboarding and support program jointly operated by Kaia Foundation and LINE NEXT to help builders successfully launch their Mini Dapps within the LINE ecosystem.

Benefits for Kaia Wave Participants:

Technical support for the Mini Dapp SDK
Potential investment opportunities
Marketing and promotional assistance

Key Features and Benefits of the Mini Dapp

The Mini Dapp SDK enables developers to easily onboard Web3 services into the LINE ecosystem, integrate payment systems, and run marketing campaigns. It comes with a set of powerful features designed to accelerate service growth :

Seamless LINE Integration

Frictionless onboarding : Users can log in instantly using their LINE accounts—no additional sign-up required.
Leverage LINE's social features : Utilize built-in features like message sharing, LIFF integration to boost user acquisition and retention.

Integrated Wallet & Payment System

Mini Dapp Wallet: Easily create a wallet via LINE or other social logins, lowering the entry barrier for Web2 users.
External Wallet Support: Seamlessly connect popular Web3 wallets like Kaia, OKX, and Bitget.
Multiple Payment Options : Sell in-game items, NFTs, and more with flexible payment options.
- Crypto payments using KAIA

Promotion & Marketing Support

TGE (Token Generation Event) Support : Launch your token with full promotional support through Dapp Portal, including exposure, campaign banners, and user engagement tools.
Reach LINE users directly : The Dapp Portal is connected to your LINE Official Account (OA), enabling visibility to millions of LINE users.
Campaigns & Events : Run reward campaigns, banners, and event pages to drive user acquisition and engagement.
LINE Messaging Integration : Send push notifications, event alerts, and re-engagement messages via LINE OA messaging.

Marketplace & Trading Features

NFT Marketplace Integration : Launch and sell your own NFT collections directly within your Mini Dapp.
Token Swap & On-ramp Support : Users can swap other tokens to KAIA or USDT, or directly purchase them using a credit card—no external services required.

How to build successful Mini Dapp

Featured on Dapp Portal

The more the Mini Dapp meets the following requirements during onboarding, the more likely it will be featured in the Dapp Portal and attract more users. Please be sure to adhere to the requirements while developing the Mini Dapp.

Requirements

Provision of services in various environments with Mini Dapp Connect

Clients must build Mini Dapp wtih two types of LINE and Web version.

LINE version

LINE version can be built via LIFF SDK. Users can easily access your Mini Dapp through LINE Messenger without install or download application. Also, Users could invite their friends and create wallet with LINE account logged in.

We strongly recommend providing Wallet Connect only when needed, rather than on the initial screen, to reduce the drop rate of users accessing the LINE version. However, since wallet integration may be essential when offering rewards, it would be advisable to place the wallet integration button where it can be easily found.

User Flow : Access Mini Dapp(LIFF) -> Consent Channel -> Add OA -> Play Mini Dapp -> Wallet Connect (at neccessary steop e.g. payment, reward)

Web version

Mini Dapp must be build in Web version to users who does not familiar with LINE Messenger. Mini Dapp SDK provides integration of web environment including wallet connection via various social account, Kaia Wallet(Mobile App/Extension) and OKX Wallet.

In the case of the web version, Wallet Connect must be provided on the initial screen for account creation. Wallet Connect does not refer to LINE Login; it refers to wallet integration provided through the Mini Dapp SDK.

User Flow : Access Mini Dapp(Web) -> Wallet Connect -> Play Mini Dapp

Compatibility between LINE and Web version

The account system of the two versions of the Mini Dapp should operate based on the Wallet Address to ensure account compatibility between the two versions.

When connecting a wallet in the LIFF and Web version, if connection proceeds with Mini Dapp Wallet(LINE) or OKX Wallet, the Wallet Address will be the same across both versions, ensuring account information compatibility. However, the Web version's Mini Dapp Wallet(Kaia Wallet App/Extension and Social logins excluding LINE) cannot be compatible with LIFF's.

For example, User A has created Mini Dapp Wallet via LINE Account 'a' from Web version, It is same with LIFF's if user logged in LINE Messenger with LINE Account 'a'.

Provision of In-app item store

Mini Dapp SDK provide payment solution both of Crypto($KAIA) and Fait(STRIPE). To create your revenue model, an in-app item store must be established.

Provision of multi-language

Mini Dapp must provide English and Japanese for users as default. Other languages can be optional as your target country. Classification user country can be done in several ways. You can either follow the browser or system language settings set by the user or determine the country based on the accessed IP address, and based on this, you should provide the appropriate language.

Provision of Point Reward

Point rewards can enhance user loyalty. These points can be used as currency within the Mini Dapp and ultimately support exchanges with tokens issued by the Mini Dapp, providing a sense of economic benefit. This can lead to explosive growth for the Mini Dapp.

Provision of information about connected wallet

It is very important to make users aware of the information about the connected wallet on any screen of your Mini Dapp. Users may enjoy many Mini Dapps and want to connect different wallets for each. By providing intuitive information about which wallet is connected and what the balance is, you can enhance the convenience that leads to payments.

Wallet Type :
Wallet Address :
- If it does not have connected wallet, use kaia_requestAccounts()
Wallet Balance :

Provision of payment status

It is very important to inform users about the payment progress status. After starting the payment using the payment creation API, the payment is processed and completed through communication with the payment gateway (PG). If the payment completion and item distribution notifications are not appropriately provided on the user's screen, they may not be able to confirm whether the payment was completed. Once the payment starts, a UI that shows the payment status should be provided during the payment process, and upon receiving the payment completion webhook, the process of distributing the items should be displayed on the payment screen.

Guide for Mini Dapp based on Landscape Mode

If your Mini Dapp is optimized for landscape mode, please ensure that it operates in landscape mode even when the user's device is set to portrait mode. It should also function in landscape mode when the auto-rotate feature is used.

Add To Home Screen

The Dapp Portal provides users with a shortcut to easily access the Mini Dapp on their mobile home screen.

"Add to Home Screen" feature is provided in two ways:

Available on the Mini Dapp detail screen within the Dapp Portal.
Provided by the Mini Dapp (the shortcut URL is provided by the Dapp Portal, and the Mini Dapp will develop a UI to integrate this URL).
1. Shortcut URL : https://www.dappportal.io/shortcut.html?dappId=dappId&register=1&&openExternalBrowser=1 *dappId: please find it on your bridge page urls or contact support channel if you don't have. *register=1: required. *openExternalBrowser=1: If opening urls from LIFF, it allow ot open in external browser.

Provision of Maintenance Mode

Please provide a maintenance screen during scheduled or emergency maintenance of the Mini Dapp to enhance user experience. In the absence of any notification during maintenance or inaccessibility, it may cause confusion among users. It would be helpful to include the estimated end time and contact information for detailed updates on the maintenance screen.

Provision of Close Confirmation Dialog

If a user accidentally presses the back button while playing a MIni Dapp, the current progress may not be saved and the Mini Dapp could be closed unexpectedly. Displaying a confirmation popup when the page is about to be closed is recommended.

You can display a confirmation popup using the following code:

Example (React)

Insert the following code in your landing page or layout component:

Example (Vanilla JS - `index.html`)

Join Us

1. 📝 Get Mini Dapp SDK

Mini Dapp SDK

Getting started is simple. Just agree to and submit the Terms & Conditions, and your Mini Dapp SDK will be issued in approximately 3 days. SDK Credentials will be delivered to the email address you've submitted.

Contact Us

Contact

If you have any inquiries regarding the Mini Dapp development, please contact us through the following channel.

📧 : [email protected]

📱 :

Kaia Wave: Builder Support Program

Kaia Wave Overview

What is Kaia Wave?

Kaia Wave: Bridging Web2 and Web3

Kaia Wave is a builder support program, brought to you by LINE NEXT and the Kaia Foundation - formed by the recent merger of Kakao's Klaytn blockchain and LINE's Finschia blockchain, to onboard new, creative builders on the Kaia ecosystem.

About Kaia

Formed through the merger of the Klaytn and Finschia blockchains initially developed by Kakao and LINE respectively, Kaia brings Web3 to the fingertips of hundreds of millions across Asia.

Key aspects of Kaia Blockchain:

Blazing Fast - Kaia has the lowest transaction latency amongst leading EVM L1s with 1-second block time and immediate finality, enabling snappy user experiences and opening possibilities for use cases that require near-real-time responsiveness.
Seamless - Support for account abstraction, gas fee delegation, and integration with the LINE and Kakaotalk messenger apps massively simplifies the user onboarding and usage experience, and gives Kaia builders instant access to over 250 million users.
Interoperable - EVM equivalence, planned support for CosmWasm, and integration with industry leading cross-chain bridges gives developers unparalleled flexibility and users a borderless ecosystem that embraces all of Web3.

More information about Kaia can be found in the official .

Qualifications and Requirements

Dapp Categories

Consumer Dapps with user rewards (Dapp points, NFTs and tokens)
No category restrictions (some DeFi Dapps may require regulatory and compliance check prior to onboarding)

Marketing Package

We offfer an all-in-one marketing solution that connects your DApp to over 196 million users through LINE Official Accounts, reward campaigns, and messaging tools.

Maximize Exposure on Dapp Portal

Dapp Portal will be the central hub where users can discover, engage with, and earn rewards from your Dapp.

Developers Resources

Kaia Docs

Overview: Kaia Docs
Developer Hub: Developers | Build dApps on Kaia
Public RPC Endpoint:
Oracles:
Indexers
Explorers:
Bridges
- Stargate:
- Wormhole:
Others
- Safe Treasury Management: Available via .
- Multichain Expansion (EVM): Available via OFT standard from and bridge technology via .
- Multichain Expansion (EVM + non-EVM): Available via .

Evaluation Criteria

We’ll be evaluating applications per the categories below.

Team
- Team track record and market reputation for other projects
Product/Service

Mini Dapp

How to build Mini Dapp?

You can check the development scope required for implementing Mini Dapps in the diagram above.

LIFF version of the Mini Dapp must be implemented through LINE Developers. More details can be found in the LINE Integration menu.

The Mini Dapp SDK supports wallet integration and payment functionality. The wallet that connects may vary depending on the LIFF and web versions. Mini Dapps can sell in-app items through the payment feature.

Additionally, if you register your information through a separate track, you may be featured on the Dapp Portal and also sell NFTs.

Overview

Key Features

Mini Dapp is a web application developed based on the LINE messenger and Kaia Blockchain. It leverages the LINE user pool to provide diverse experiences and rewards to about 200 million global users. Unlike LINE MINI Apps, Mini Dapp can offer not only points and cash-like rewards but also Web 3-based rewards. Additionally, Mini Dapps can provide the same services to users who are not LINE users. Using LINE Messenger's Official Account for promotions and friend invites can help gather more LINE-based users.

Also, Mini Dapp should provide various functions including Play, Wallet, Payment and Reward. See the key features below.

Sample Mini Dapp

Explorer Various Mini Dapps from Dapp Portal

LINE Version : https://liff.line.me/2006533014-8gD06D64
Web Version : https://dappportal.io
- Please open the link on LINE Messenger App from Mobile

Mini Dapp Demo

Please refer to below Mini Dapp Demo to build your Mini Dapp.

LINE Version:
Web Version:

LINE Integration

LINE Developers

Integrate LINE Platform

There are 9 steps that need to be taken to build a Dapp via LIFF.

Sign up LINE Business Developers account using your LINE Account or business account. You can use this account when you integrate LINE services to your Mini Dapp.

Register Developer name and email to LINE Developers account to create a developer account. When you first log in to the LINE Developers, You need to register name and email address.

A Provider can be an individual, company or organization that provides services through the LINE Platform.

A Channel is a communication path between the LINE Platform’s functions and a provider’s services. Channels must have a name, description and icon image. You MUST select LINE Login type when you create Channel to build LINE Mini Dapp. Blockchain Service and LINE MINI App type are not related to Dapp Portal.

You should create LINE Official Account to use Messaging API which is to be integrated to Channel you’ve created from Step 4.

Please select "Company or owner's country or region" as the actual country of origin for Mini Dapp publisher.

If you have created successfully LINE Official Account from Step5, you should enable Messaging API function on LINE Official Account Manager – Setting page. When enabling the use of Messaging API in the LINE Official Account Manager, a Messaging API channel is created on LINE Developer’s console under same Provider automatically.

07. Integrate Official Account to LINE Developer’s Channel

Once Messaging API is enabled, you can link Official Account to Channel on Basic setting page.

To use LIFF SDK, You need to add the Mini Dapp URL to your channel and get LIFF ID. You can set LIFF applications on LINE Developers Console – Channel – LIFF tab.

If you’ve completed Step 8, You can build Mini Dapp as LIFF version using LIFF SDK.

LINE Front-end Framework (LIFF)

Mini Dapp should build web application as LINE version with LIFF SDK.

Introduction

Official Document : LINE Front-end Framework (LIFF)

Web app connecting with LINE users

The LINE Front-end Framework (LIFF) is a web application framework provided by LY Corporation. When you integrate the LIFF SDK into your web app, you will be able to access information provided by the LINE Platform or use functionalities provided by the LINE app.

LIFF is integrated with LINE Login. Without having to deal with complicated settings, you can safely access a user's profile information via the LINE Platform's authorization flow.

The share target picker is a tool for sending messages to LINE friends who you can select via LIFF app. Even without opening a chat room the developer can send messages to LINE friends, so you can use this feature to connect users with services, send information, and add social elements.

Cross-browser support

LIFF is cross-browser compatible. Most APIs are compatible with desktop browsers, so they will work both with regular web browsers as well as with LINE apps.

Providing utility

We're providing various convenient utilities to support LIFF developers. You can easily retrieve the LINE app's version or the OS type. We also provide a QR code reader out of the box.

Various screen sizes

For running on the LINE app we're providing three different screen sizes that each have their own advantages.

Essential Settings

Setting for data collection from LIFF via Mini Dapp SDK

Go to LINE Developers console
Click Channel which integrate LIFF
Click LIFF app name
Edit Scope checked with 'openid'

To use features such as URL sharing, minimizing the browser, and page refresh within your LIFF Version, you need to enable the action button.

How to set it up: Go to LIFF settings > Options > Module mode > Disable

The action button is only available where Module mode is turn off.

When playing a Mini Dapp in a chat room, the user may want to perform another action, such as sending a message to the chat room. In this case, minimizing the LIFF browser will suspend playing the Mini Dapp and allow the user to perform the action without disconnetion from Mini Dapp. After performing the action, the user can resume playing the Mini Dapp by maximizing the LIFF browser.

Invite Friends

Guide

Invite friends feature is only available in Mini Dapp (LIFF).

Mini Dapp SDK

Authorization

Mini Dapp must get clientId and clientSecret to integrate Mini Dapp SDK. This credentials can be activated once service domain has been registered to clientId.

Create Project

To officially open the Mini Dapp, registration of a service domain is mandatory. Be sure to request registration after getting service domain.

If a service domain for the application has not been built, you can use the local environment path for testing. Please use http://localhost:3000.

To use the paymentProvider, a clientSecret is required. DO NOT share clientSecret to public. If it has been exposed, please request to issue a new clientSecret.

Install SDK

Add Mini Dapp SDK into your project via npm or yarn.

Initiate SDK

Mini Dapp MUST call DappPortalSDK.Init() when the user executes Mini Dapp. In case of LIFF version, the must be done after liff.init() is completed.

At this stage, you only need to implement up to DappPortalSDK.Init() and completing the Mini Dapp Connect is not required at this stage. Mini Dapp Connect(Wallet Integration) within the LIFF environment should only be triggered when necessary (e.g., to receive on-chain rewards, make item purchases), not upon initial LIFF entry.)

Background : This approach is necessary to handle data for active user verification in the Mini Dapp. This data is crucial for performance measurement and developing user acquisition strategies.
Notice : Following this guide will provide LINE NEXT with the encrypted information of LINE users connected to the Mini Dapp.

class DappPortalSDK

1. DappPortalSDK(config: DappPortalSDKClientConfig)

Initialize SDK using clientId.
The previously provided clientId is used. The SDK only runs on the pre-agreed Host address.

DappPortalSDKClientConfig

clientId: string
chainId: string
SDK is running on production env basically. If you want to connect testnet, use ‘1001’.

2. getWalletProvider(): WalletProvider

You can get WalletProvider which is compatible with EIP-1193 interface.

3. getPaymentProvider() : PaymentProvider

You can get PaymentProvider which support process and history of payment.

4. isSupportedBrowser(): boolean

It is function to verify compatibility between SDK and Browser.

5. showUnsupportedBrowserGuide(): Promise

It will show a screen how to use an external browser if current browser is not supported.

How to Get SDK Authorization

To integrate Mini Dapp SDK, you need to get clientId and clientSecret from Dapp Portal team.

1. Sign contracts with Dapp Portal team.

Initiate DappPortalSDK

Initiate SDK

1. Initialize SDK via `init()` method

import DappPortalSDK from '@linenext/dapp-portal-sdk'

const sdk = await DappPortalSDK.init({ clientId: '<CLIENT_ID>', chainId: '1001 });

Parameters

Name

Description

Response Returns a DappPortalSDK object through which the following methods can be called.

method name

description

We highly recommend executing DappPortalSDK.init() only once and managing it as a singleton object. If you create a new DappPortalSDK object by calling DappPortalSDK.init() every time you make a request to the wallet, it may lead to malfunction. The reason we do not enforce this as a singleton is to support scenarios where multi-configurations are needed. For example, if you want to use both testnet and mainnet in a single app. In such cases, we also recommend managing one singleton DappPortalSDK object for testnet and another singleton for mainnet.

Domain Verification via Reown

How to work Bitget Wallet from Mini Dapp SDK

The Mini Dapp SDK provides Bitget Wallet via WalletConnect. To offer Bitget Wallet through the Mini Dapp SDK, the domain verification required by WalletConnect must be completed beforehand.

Please follow the guide below to complete the domain verification and share the ProjectId generated by Reown with the Dapp Portal team.

❗Even if you upgrade to the SDK version that supports Bitget integration, you will not be able to use Bitget Wallet unless the domain registration and ProjectId submission are completed.

Guide to add your domain via Rewon Dashboard

References.

Domain should be registered entirely including protocol, http:// | https://
Please ensure that a slash (/) is notincluded at the end of the domain when registering the record.

1. Access Reown Dashboard and Initiate Verification

Log into your Reown account on the dashboard. ()
Go to Domain tab
Add domains you wish to add as allowlist

2. Submit ProjectId to Dapp Portal team

Sumit ProjectId after verification to add it to Mini Dapp SDK.
Telegram: @dappportal_official
- If you are using a technical support channel through a different route, you can share ProjectId through that channel.

Policy

Cancellation

STRIPE

Case.1 : In the case where create API is hosted but SDK's startPayment has not been excuted
- Max time for cancellation : 2100sec + 180sec
- Response if payment is excuted after cancellation : Error when hosting SDK's startPayment
Case.2 : SDK's startPayment is excuted but users don't approve on STRIPE page
- Max time for cancellation : 400sec + 180sec
- Response if payment is excuted after cancellation : Cannot payment excute with expiration

CRYPTO

Case1. In the case whare creat API is hosted but SDK's startPayment has not been excuted
- Max time for cancellation : 2100sec + 180sec
- Response if payment is excuted after cancellation : Error when hosting SDK' startPayment
Case2. SDK's startPayment is excuted but users don't approve transaction

Release Note

Latest Version (v1.4.8)

v1.4.8

Release Date

Nov 17th 2025 06:30 in UTC

Note

npm:
cdn:

What's improved

Bitget Wallet Integration Improvement
- In the previous version, transactions signed on the mainnet were incorrectly displayed as being on the Kairos (testnet) network.
  This issue has now been fixed, and mainnet signatures will correctly display as “Kaia.”

v1.4.6

Release Date

Oct 15th 2025 06:00 in UTC

Note

v1.4.5

Release Date

Sep 22nd 2025 07:00 in UTC

Note

v1.4.4

Release Date

Sep 5th 2025 09:30 in UTC

Note

npm:
cdn:

What's improved

Output error logs when not using the latest version of the Mini Dapp SDK (Note: these error logs do not affect the SDK's functionality).
Fixed the error occurring during the reconnect process after calling disconnectWallet(). (Bitget Wallet).

We always recommend using the latest version of the Mini Dapp SDK to ensure security and compatibility.

v1.4.2 & v1.4.3

Release Date

August 21st 2025 09:00 in UTC

Note

Note

Fixed minor bug for Kaia Wallet(App).

v1.3.7

Release Date

July 10th 2025 08:00 in UTC

Note

In version 1.3.7, the Mini Dapp SDK has been updated to work properly within the in-app browser of the Kaia Wallet (App).

npm:
cdn:

Note

Bugs that may occur in Mini Dapp SDK v1.3.0 and above have been fixed.

npm:

cdn:

[No issue] When there is sufficient interval between initializing SDK and calling methods

April 10th 2025 06:00 in UTC

Note

NPM : https://www.npmjs.com/package/@linenext/dapp-portal-sdk/v/1.2.11

CDN :

The bug has been fixed where requesting kaia_accounts() would show the wallet connection screen when there was no connected wallet, and the Client would respond with [].

Starting from Mini Dapp SDK v1.2.11, when requesting kaia_accounts() with no connected wallet, the Client can get response with [] without showing the wallet connection screen.

v1.2.10

Release Date

April 7th 2025 10:00 in UTC

Note

NPM :

v1.2.9

Note

https://www.npmjs.com/package/@linenext/dapp-portal-sdk/v/1.2.3

Fixed minor bugs

v1.2.2

Release Date

January 21st 2025 15:00 in UTC

Backend

v1.2.1

Release Date

January 21st, 2025 06:00 in UTC

Backend

v1.2.0

Green > Mandatory to be applied to Mini Dapp's code

Blue > Optional to be applied Mini Dapp's code if Mini Dapp need to new function.

Release Date

January 20th, 2025

Back End

Wallet
- Improved response so that clients can clearly aware for the cancellation and closing options of the popup.
Payment

Web

Wallet
- Improved response so that clients can clearly aware for the cancellation and closing options of the popup.
- Fixed UI bug if Mini Dapp name includes character of '

Mini Dapp SDK

Wallet
- Improved response so that clients can clearly aware for the cancellation and closing options of the popup.
- Fixed UI bug if Mini Dapp name includes character of '
- Fixed z-index onto popup to proceed sign if bocked

Mobile, Extension

Wallet
- personal_sign() is supported.

Integration Guide for Game Engine

Design Guide

Set Browser Tab Name

To indicate that it is a family service of the Mini Dapp ecosystem, please set the browser tab name in the format asName | Mini Dapp.

Set OpenGraph

The LIFF/Web URL of the Dapp can be utilized across various marketing channels. If Open Graph is not set up, it may reduce the effectiveness of content delivery. Therefore, please ensure that Open Graph is properly configured. Without it, blank spaces or alternative text may appear where the link is displayed.

Connect Button design

If Wallet Connect is integrated when initiating specific actions (such as Buy, NFT Airdrop, FT Airdrop, etc.) rather than using a standard button, please ensure that Wallet Connect is triggered when those actions are executed. It is acceptable for Wallet Connect not to be initiated based on the button guidelines provided. However, if you create a button similar to Wallet Connect, please make sure to adhere to the aforementioned guidelines.

Set z-index for pop-up

z-index for SDK's pop-up to prevent blocking new windows from Browser set as '999'. Please set your z-index for any pup-up under '999' to avoid conflicting between pop-up's

Dapp Portal

Home

To be listed on the Dapp Portal, registration of information through Ops Support is required. Additionally, the Dapp Portal evaluates the completeness and reward systems of each Mini Dapp comprehensively and places them in prominent positions."

Trade

Dapp Portal provides exchange services for FT which is issued by Mini Dapp. Also, Dapp Portal supports on-ramp(Purchase) and off-ramp(Cash Out) to users who are unfamiliar with Web3 assets.

Market

The Dapp Portal offers an NFT marketplace that is not provided in the Mini Dapp's in-app item store. If you wish to create and sell NFTs, you must submit the information according to the Ops Support guide. NFTs that are self-issued without following the guide will not be listed on the Dapp Portal.

My

In the My tab of the Dapp Portal, you can check your owned assets and view popular Mini Dapps or Mini Dapps you have previously visited.

Mini Dapp Information

Mini Dapp Name

Displayed in A of the Screen Sample
English Only

Collection & Drops

1. Submit Information for NFT Collections and Drops

You should submit information for NFT Collections and Drops if you have plan to launch NFT Drops or NFT Airdrop. You can see the contents what you need to submit.

Meta Data Format

Collection Information

Collection Name

Displayed in A of the Screen Sample
English Only

Token Symbol

Symbol of Collection
eg) Collection: Bellygom World Official / Symbol: BELLYGOM

Collection Description

Displayed in B of the Screen Sample
The multilingual language support is: EN (English), JA (Japanese), TH (Thai), TW (Traditional Chinese). All the lanuages must be filled.

Create Earning

Create Earning: Fee information received by the Creator in C2C transactions
Wallet Address | %(Fee)
- Create Earning fee can be set between 1% and 10%

Drops Earning

Drops Earning: Fee information received by the Mini Dapp in B2C sales
If it is the same as the Wallet Address entered for Create Earning, you may leave it blank
Wallet Address

Collection Main Image

Displayed in C of the Screen Sample
Please select and upload the main image from the Origin contents (NFT images).
Image Size: 408x408

Collection Background Image

Displayed in D of the Screen Sample
Image Size: 1125x459

Upload NFT Information

A. Pre-reveal(Optional)

This feature is used when original content needs to be disclosed at a specific time. It is unnecessary if the NFT at the time of purchase is the same as the one being held.

Collection Name

Please enter one of the issued collections.
English Only

Description

List of Supported languages in the Dapp portal
All languages are required.

Pre-reaveal Image

Image Size: 600x600

B. Original Contents(Mandatory)

Collection Name

Please enter one of the issued collections.
English Only

Image

Image Size: 600x600

Meta

Please input the NFT's metadata in the specified format and upload it.
Meta Data Format

Guidelines for Meta data
- Please write the NFT name within 50 characters.
- The description can be up to 1,000 characters.
- You can add up to 30 attributes.

If you need to set values outside of these specifications, please let us know.

Revealed date

ex) yyyy-mm-dd tt:mm (in UTC)

Fungible Token Information

If you want to expose it in the Dapp Portal Wallet or Kaia Wallet's search list, please submit it.

Token Name

English Only

Reward System Flow

Reward system flow

Mini Dapp can list the mission-reward(KAIA/USDt, NFT, point) implemented within their Dapp on the Dapp Portal. Each reward is listed and tracked on the Dapp Portal in the following ways.

KAIA/USDt Reward

The Dapp Portal tracks the transactions of the EOA Wallet (for rewards) submitted by the Dapp. When a transaction of a specific amount occurs from that wallet to a specific user's wallet, the portal recognizes that the mission has been completed and the reward has been distributed. Due to this characteristic, a separate wallet must be prepared for each mission if you are running multiple missions. If the same wallet is used for rewards for multiple missions, the Dapp Portal will not be able to recognize which mission was completed.

*Reward distribution for mission completion must be implemented by the Dapp. For information on sending KAIA or USDt, please refer to .

NFT Reward

The Dapp Portal tracks the transactions of the EOA Wallet from which the NFT submitted by the Dapp is distributed and references the contract address. The EOA Wallet must be submitted to the Dapp Portal team when minting the NFT, and the Dapp Portal team will airdrop the NFT to that wallet.

*Due to the functionality of the Dapp Portal, tracking is only possible when a single NFT is distributed in a single event.

Point Reward

The Dapp Portal does not currently track the flow of point rewards. It simply lists a URL to the page where points can be acquired. The policy and features regarding point movement and balance tracking may change in the future.

Policy

GRAC(South Korea)

Purpose

For users accessing from IP based on South Korea, only Mini Dapps that have obtained a reting classification from GRAC(Game Rating and Administration Committee) may be served normally.

If a Mini Dapp is game-like and lacks a valid rating, Users from Korean IPs will see a "This service is not available in your country" notice and access will be blocked when users execute the Mini Dapps.

You can find detailed policies on the GRAC website.

Scope

Applies to Mini Dapps with game-like characteristics (core game mechanics such as progression, rewards, competition, chance-based items, etc.).
Non-game utilities are generally out of scope, subject to review.

Effective Date

Start Date: From August 22, 2025

Policy Summary

Allow: Korean IP AND approved GRAC Status
Block: Korean IP AND no approved GRAC status
Exception: Non-game Mini Dapp

What Developers Must Provide

GRAC rating info (rating, decision number, decision date)
Evidence (certificate PDF/image and/or official lookup URL)

Checklist for determining whether it qualifies as a game contents

Characteristics

Description

Extra Packages

Playbook for Teams

Ranking & Metrics

To maximize your score, you must excel at increasing weekly on-chain active accounts, weekly on-chain transactions, and Mini Dapp revenue.

There are a few points to keep in mind:

On-Chain Active Accounts:

FAQ

SDK Issuance & Environment Setup

Q. When will the SDK be issued?

A. The SDK will be issued within 3 business days from the date of submitting the SDK T&C. The clientId and clientSecret will be sent to your registered email.

Q. Do we need to develop both Web and LINE(LIFF) versions?

A. Yes, that’s correct. The LINE(LIFF) version is designed for LINE users and allows seamless access within the LINE mobile app. On the other hand, the Web version is accessible via mobile browsers or PC environments, and it's intended for non-LINE users who do not use LINE Login.

Q. Do we need to configure chainId for the SDK?

A. Yes. The chainId is used to distinguish between the testnet and mainnet environments. By default, it is set to testnet(chainId: 1001). During development, please use the testnet to test wallet integration and payment flows. For real payment testing or official launch, you must switch to the mainnet(chainId: 8217).

Q. Where can I get updates about SDK version changes?

A. SDK version updates are announced through the official Telegram channel. 📢 Once you join, you’ll receive the latest updates and announcements related to the SDK.

Q. Can I integrate the Mini Dapp SDK with Unity or Cocos engine?

A. Yes, you can. By porting your Unity or Cocos project to WebGL, you can integrate it as a web application using the Mini Dapp SDK. For detailed instructions, please refer to the integration guide.

Q. Do you provide sample code?

A. Sample code is provided in the following document.

Sample code by method:
Full integration sample code:

Wallet Provider

Q. Why does an “Invalid Origin” error occur and wallet connection fail?

A. The SDK only works properly on domains registered in the whitelist. Please share your test domain via the Tech Support Channel or email, and we will assist you in registering it to the domain whitelist.

Q. Why is the wallet connection window not opening?

A. If DappPortalSDK.init() is repeatedly called on every request in the Web/LIFF version, it may cause malfunction. Therefore, we strongly recommend calling DappPortalSDK.init() only once during app startup and managing it as a singleton instance. In addition, for the LIFF version, make sure to call DappPortalSDK.init() after liff.init() has been successfully completed.

Q. Why does OKX Wallet fail to connect or require re-entry to the Mini Dapp on certain devices when using kaia_requestAccounts and personal_sign?

A. This issue is typically caused by timing conflicts during the signature step after wallet connection. To ensure a more stable experience, we recommend using kaia_connectAndSign instead.

Q. How can I persist the Wallet Connect session when re-entering or refreshing the Mini Dapp after wallet connection?

A. First, call kaia_accounts to check if there is an existing connected wallet.

If a connected wallet is found, you can use that wallet information directly.

Q. Why is it necessary to implement disconnectWallet()?

A. You need to implement disconnectWallet() in the following cases:

When the user has lost the password for the previously connected wallet,

Q. Can I provide external wallets such as MetaMask instead of using the Mini Dapp SDK wallet integration?

A. No, it is not allowed. To launch a Mini Dapp, you must use the wallet integration method provided by the Mini Dapp SDK. External wallet integrations such as MetaMask are not supported.

Q. How are user accounts identified?

A. In both Web and LINE(LIFF) versions, user accounts should be distinguished by their wallet address. However, in the LINE version, users can enter the Mini Dapp without connecting a wallet. In such cases, you should temporarily create an account based on the user's LINE ID upon first entry, and map the Wallet Address to that account once the wallet connection is completed.

Q. Should accounts be compatible between Web and LINE(LIFF) versions?

A. Yes. Both Web and LINE(LIFF) versions support wallet types such as LINE, OKX, and Bitget Wallet. If the same wallet address is used in both environments, it is recommended to maintain compatibility between the accounts for a seamless user experience and consistent login and asset information.

Q. Can I retrieve LINE ID or profile info via LINE Login in the Web version?

A. No, the Web version does not support LINE Login. If implemented, it must be removed. The Web version is intended for non-LINE users, including PC users, and should not include features that require LINE authentication. LINE-related features should be provided only in the LIFF version.

Q. Is there a way to distinguish between LIFF and Web browser environments?

A. Yes. You can use the liff.isInClient() method to detect the environment.

If liff.isInClient() returns true: This indicates the LIFF environment. In this case, run liff.init() first, then call DappPortalSDK.init()

Q. Why is Bitget Wallet not shown in the wallet selection list?

A. To display Bitget Wallet in the wallet list, you must register a projectId. Please follow the to create a projectId, then submit it through the Tech Support channel for registration.

Q. What causes unknown errors when signing a transaction with a connected wallet?

A. This may occur if the Wallet Address requesting the signature differs from the actual signing Wallet Address. Please check that the Wallet Address connected via:

Web:
LIFF:

Payment Provider

Q. Do we need to support both Crypto and Stripe payments?

A. Yes, both payment methods must be supported. However, if adjustments are required due to specific service structures or policies, you may selectively support one method after consultation with the BD or Tech Support channel.

Q. Why does an error occur during payment testing?

A. Please first check whether the parameters you provided match the in the documentation. Even if the code seems correct, errors may still occur during testing. If the issue persists, please contact the Tech Support channel for assistance.

Q. What are lockUrl and unlockUrl?

A. These are useful features when selling products with limited stock. They temporarily “lock” the quantity while a user is attempting to purchase the product, preventing other users from buying the same item simultaneously. This mechanism helps avoid duplicate purchases during the payment process and enables more accurate inventory management.

⚠️ Note: If the product has no quantity limit, set both lockUrl and unlockUrl to null.

Q. Crypto payment works, but why does Stripe payment fail? (An error code 500 is returned when startPayment() is called)

A. This usually happens when the imageUrl parameter is invalid or not accessible from outside. Please make sure the product image URL is valid and publicly accessible.

Q. Why isn’t the webhook being received?

A. The paymentStatusChangeCallbackUrl must be accessible over the public network. You should either:

Make the URL publicly accessible, or
Whitelist the Dapp Portal server IPs.

Q. Why does createPayment succeed but startPayment return an error? (An error code 400 is returned when startPayment() is called)

A. This indicates that something went wrong during the startPayment phase. Please check the paymentId and the returned error code used in the test. For root cause analysis and further assistance, share the details via the Tech Support channel.

Q. What causes an "Internal JSON-RPC error" or a blank payment screen to appear?

A. This issue typically occurs when the configured chainId and testMode values do not match.

Testnet: chainId: 1001, testMode: true

Q. How can I perform real payment testing?

A. Real payment testing is only available after your settlement information has been updated. This update is completed after your team submits the Due Diligence (DD) form.

Once your launch schedule is confirmed, the Kaia Wave team will request your DD submission. In general, real payment testing becomes available three business days before the official launch.

If you need to test earlier, please contact the Tech Support channel to request an exception.

⚠️ Note: Real payment tests are non-refundable, so please proceed with caution.

Q. Is there a minimum payment amount for products?

A. Yes, there is a minimum payment threshold:

USD: Minimum of $0.5
KAIA: Minimum of 0.01 KAIA

For more details, please refer to the

Q. Is it mandatory to apply exchange rates for Crypto payment products?

A. Yes, you must provide a converted price based on the current market rate. This ensures transparency for users and accuracy in payment processing.

While the SDK does not provide exchange rate conversion, you can use external services such as:

CoinMarketCap(CMC)

Q. Why is it necessary to provide a payment history feature?

A. Users must be able to view their own payment history, which:

Increases user trust
Helps customer support(CS) by referencing paymentId and other data

LINE Integration

Q. How do I create a LINE Developers account?

A. Developers must use their personal LINE account to create a LINE Business ID (Provider).

Shared or team accounts are not supported in Dapp Portal.

If you're unable to create the account, please contact the Tech Support channel for assistance.

Q. What should I do if I can't create a LINE MINI App?

A. Mini Dapp do not support LINE MINI App. Instead, use a combination of the LINE Login channel and Messaging API channel to build your LIFF version.

Please build your LIFF app based on the LINE Login channel, not LINE MINI App.

Q. How should I set the "Region to provide the service" when creating a LINE Login channel?

A. This setting should reflect the primary target country of your service, not the country where your company is incorporated.

Regardless of the selected region:

All LINE-available countries can access your service

Q. How do I create a LIFF URL?

A. Follow these steps:

LINE Login Channel → LIFF → Add → Fill in LIFF Details

LIFF app name: Your dApp service name
Size: Full

Q. How do I enable OA Aggressive Add Friend mode?

A. Follow these steps:

LINE Login Channel → LIFF → LIFF Detail → Add Friend Option → On (aggressive)

Q. Why am I getting a 403 error when accessing the LINE(LIFF) version?

A. LIFF URLs are inaccessible if the LINE Login channel is not in Published status. Please switch to Published mode when submitting your Demo or performing tests.

Q. Is it okay to publish the LINE(LIFF) version before launch?

A. Yes. As long as you do not share the LIFF URL or test domain externally, general users won’t have access.

Publishing early can help streamline Demo submission and testing. If you must test without publishing, you can add the reviewer’s email as an admin to the LINE Login channel.

Web3 Provider

Q. What causes the error: “Sending transaction was failed after ~ try, network is busy”?

A. This is a temporary error caused by high network traffic. If this occurs, simply retry the transaction — it should eventually succeed.

Payment

01. Payment Flow

Flowchart

Polling

Webhook

1. Triggering createPayment API from Mini Dapp

When a user requests a purchase, the Mini Dapp Client sends the item information to the Mini Dapp Server. The Mini Dapp Server then calls the createPayment API on the Dapp Portal Payment Server. The createPayment API responds with a payment ID in the format: { id: <payment_id> }.

Request

Response

2. Get paymentProvider from sdk instance.

The Mini Dapp Client retrieves the PaymentProvider instance from sdk with getPaymentProvider method.

3. Start payment process via paymentProvider.

Then, call the startPayment method of the paymentProvider, passing the paymentId received from step 1 as a parameter.

4. Check payment status and finalize payment.

There are two ways to check the payment status:

Client-side: Wait for the promise returned by the startPayment method to resolve. When the promise resolves, the payment status is updated to FINALIZED

Server-side: Handle the payment status via a webhook event on the server. When using webhooks, the Dapp Portal Payment Server sends an update to the paymentStatusChangeCallbackUrl specified in the parameters of the createPayment API whenever the payment status changes. The update request is sent as an HTTP POST , and the body includes the updated payment status in the following format:

If the received status is CONFIRMED, the Mini Dapp Server should send a request to finalize the payment by calling the following API:

5. In case of payment canceled by system.

If an HTTP 200 OK status is not returned in response to the webhook event, the event will be retried up to four times at exponential intervals: 1, 2, 4, and 8 seconds.

After all retry attempts have failed, if a lockUrl was specified when the payment was created, the Dapp Portal Payment Server will send an unlock request as an HTTP POST . The body includes the paymentId and itemIdentifiers.

This ensures that any reserved resources (e.g., NFT items, inventory) are released properly in case the payment status could not be confirmed via webhook.

6. You can open payment history page via paymentProvider. Promise will be completed if payment history page opens successfully.

02. Payment API

baseUrl for Payment API: https://payment.dappportal.io

1. create payment

post /api/payment-v1/payment/create Parameters

Name

Description

Request Body

Example Value

Schema

field

limitation

Items(*)

field

limitation

Responses

HTTP Status Code

description

Request Example

2. get payment information

get /api/payment-v1/payment/info

Parameters

Name

Description

responses

HTTP Status Code

Description

field

limitation

Items(*)

field

limitation

Request Example

3. get payment status

get /api/payment-v1/payment/status Parameters

Name

Description

Responses

HTTP Status Code

Description

field

limitation

Request Example

4. finalized payment

It will be ready to be settlement after requesting finalize payment API.

You can't get settlement for STRIPE transaction if you did not request finalize payment API. For CRYPTO, We recomment to request finalize payment API too. Parameters N/A

Request Body

Example Value

Schema

Responses

HTTP Status Code

Description

Request Example

03. PaymentProvider

sdk.getPaymentProvider()

Initializes the paymentProvider, allowing developers to use various payment features.

Parameters

N/A

Responses

paymentProvider.startPayment()

Calling paymentProvider.startPayment() displays a transaction window to the user and begins the payment process.

Parameters

payment_id *required · string

Responses

Error

Code

Description

paymentProvider.openPaymentHistory()

This method opens a payment history window. In order to complete the operation, a signature from the user is required.

Parameters

N/A

Responses

04. Payment Webhook

Each Webhook's callback URL should be set differently.

If lockUrl and unlockUr is not needed, please enter null.

1. lock event

lockUrl is a server endpoint that is called to temporarily lock or reserve the item being purchased. This is typically required for items with limited quantity or NFTs, to prevent overselling and ensure that no other user can purchase the item while the current payment is in progress.

If the lockUrl parameter is included in the create payment request, a POST method request for the lock webhook event will be made.

When the payment is initiated using the SDK’s startPayment function, the webhook event is requested just before starting the user’s payment flow if it is determined that the payment can proceed normally.

If a request is made with the lockUrl but a 200 response is not received, the payment will be immediately canceled and marked as failed automatically.

2. unlock event

unlockUrl is a server endpoint that is called when a payment fails, is canceled, or times out, in order to release the previously locked item and make it available for others to purchase again.

If the unlockUrl parameter is included in the create payment request, a POST request will be sent to this endpoint when a payment failure-related event is triggered.

If the payment is successfully completed (status === CONFIRMED), the unlockUrl will not be called. Instead, the item is typically finalized via a separate process (finalize API or internal logic).

If a request is made with the unlockUrl but a 200 response is not received, it will be retried up to 5 times at intervals of 1, 2, 4 and 8 seconds. To avoid that the item remains locked, implementing background job to attempt unlocking again is recommended.

3. payment status change event

When creating a payment request, a payment status change webhook event will be sent to the paymentStatusChangeCallbackUrl you've provided.

An event occurs whenever the payment status changes, except when the status is CREATED.

If the status of the received webhook is CONFIRMED, you can call the finalize payment API.

If a request to the paymentStatusChangeCallbackUrl does not receive a 200 response, a maximum of 5 retries will be made at intervals of 1, 2, 4, and 8 seconds. Even if a 200 response is not received after 5 retries, the payment cancellation will not proceed.

Status

Description

(*) This status can only be queried through the get payment information API.

line-mini-dapp

LINE's Mini Dapp & Dapp Portal

Introduction

Kaia Wave Program

Key Features and Benefits of the Mini Dapp

Seamless LINE Integration

Integrated Wallet & Payment System

Promotion & Marketing Support

Marketplace & Trading Features

How to build successful Mini Dapp

Featured on Dapp Portal

Requirements

Provision of services in various environments with Mini Dapp Connect

LINE version

Web version

Compatibility between LINE and Web version

Provision of In-app item store

Provision of multi-language

Provision of Point Reward

Provision of information about connected wallet

Provision of payment status

Guide for Mini Dapp based on Landscape Mode

Add To Home Screen

Provision of Maintenance Mode

Provision of Close Confirmation Dialog

Example (React)

Example (Vanilla JS - index.html)

Join Us

1. 📝 Get Mini Dapp SDK

Mini Dapp SDK

Contact Us

Contact

Kaia Wave: Builder Support Program

Kaia Wave Overview

What is Kaia Wave?

About Kaia

About Kaia

Qualifications and Requirements

Dapp Categories

Marketing Package

Maximize Exposure on Dapp Portal

Developers Resources

Kaia Docs

Evaluation Criteria

Mini Dapp

How to build Mini Dapp?

Overview

Key Features

Sample Mini Dapp

Explorer Various Mini Dapps from Dapp Portal

Mini Dapp Demo

LINE Integration

LINE Developers

Integrate LINE Platform

07. Integrate Official Account to LINE Developer’s Channel

LINE Front-end Framework (LIFF)

Introduction

Web app connecting with LINE users

Integration with LINE Login and the LINE Platform

Share target picket: A powerful tool for sending messages

Cross-browser support

Providing utility

Various screen sizes

Essential Settings

Setting for data collection from LIFF via Mini Dapp SDK

Invite Friends

Guide

Invite friends feature is only available in Mini Dapp (LIFF).

Mini Dapp SDK

Authorization

Create Project

Install SDK

Initiate SDK

class DappPortalSDK

1. DappPortalSDK(config: DappPortalSDKClientConfig)

DappPortalSDKClientConfig

2. getWalletProvider(): WalletProvider

3. getPaymentProvider() : PaymentProvider

4. isSupportedBrowser(): boolean

5. showUnsupportedBrowserGuide(): Promise

Example (Vanilla JS - `index.html`)

1. Initialize SDK via `init()` method

1. Access Reown Dashboard and Initiate Verification