Overview

This guide is meant to help you integrate connected browser wallet signing with Shinami Gas Station transaction sponsorship. We show an integration flow diagram with links to associated sample code.

Shinami's Gas Station only supports integration with your app's backend (no CORS support) for security reasons. This limits exposure of your Gas Station access keys. If these keys are leaked, bad actors have the ability to sponsor transactions from your fund until it has been drained or you disable the key in your Shinami dashboard.

If you have not already set up a Shinami Gas Station Fund and Access Key, and sent a successful sponsorship request, see our Gas Station tutorial for guidance.

Examples

Sample app overview

We've created a sample app with a React frontend that uses Sui dApp kit and a backend using the Shinami TypeScript SDK. It integrates with Sui Wallet and a few other connected browser wallets out of the box. We've included it in our shinamicorp/shinami-examples repo . It's not meant as a starter template for a production app (as an example its API endpoints have no authentication mechanism). Instead, it's meant to show you a very simple working example so you can understand the core concepts involved. It includes a README.md file to help you get it up and running quickly if you want to see a working example. Otherwise, you can just follow the diagram and associated links to the code below.

Build and sponsor on the BE, sign on the FE, submit on the BE

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Summary of steps

The links in the steps below take you to the relevant code locations in our sample React + TypeScript app on GitHub. The key functions in the sample app are connectedWalletTx on the frontend and /buildSponsoredtx and /executeSponsoredTx on the backend.

1. Frontend: Send a request to your app's backend to build and sponsor a transaction. Include any data from the FE needed to build the transaction. In our case, that's the sender's address and the two integers the user submitted in the form on the page (sample code).
2. Backend: Build a gasless Move call transaction with the numbers the user provided. (sample code). Because we are using the Shinami TypeScript SDK, this produces a GaslessTransaction, which is just an interface that contains all the required and optional values our gas_sponsorTransactionBlock endpoint accepts.
3. Backend: Set the sender's address (provided by the frontend) and get the transaction sponsored via a gas_sponsorTransactionBlock request to Shinami's Gas Station. (sample code).
4. Backend: Handle the response and, if successful, return the sponsored transaction and the sponsor's signature to the frontend (sample code).
5. Frontend: Obtain the sender's signature over the transaction (sample code).
6. Frontend: Make a request to the backend to submit the transaction to the chain. Include the transaction and sponsor signature, along with the newly-acquired sender signature (sample code).
7. Backend: Submit the transaction and both signatures to the chain with a sui_executeTransactionBlock request (sample code).
8. Backend: Handle the response as needed.
9. Backend: Response to the frontend. In our sample app, we send back the SuiTransactionBlockResponse from the Full node. (sample code).
10. Frontend: Handle the response as needed. In our sample app, we poll a Sui Full node until it has a record of the transaction and then print the user's math result that was included in the transaction (sample code).

Appendix

Signing with an embedded zkLogin wallet tied to your app

This follows a very similar flow to the example above. The key difference is that the frontend signs with the user's ephemeral KeyPair and the backend assembles the zk signature using the emphemeral signature and the zkProof. For an image of this flow, see the README of our Next.js zkLogin SDK.