Solana Multisig Transaction Decoder

Decode Squads multisig transactions and render human‑readable instruction details using Anchor IDLs. A minimal Express server serves a static UI and an API endpoint.

Prerequisites

• Node.js 18+ and npm
• Internet access (fetches IDLs, calls Squads API and a Solana RPC)

Install

npm install

Run locally

• Dev (auto-restart):

npm run dev

• Prod:

npm start

The server listens on http://localhost:5173 by default. Override with:

PORT=3000 npm run dev

Using the UI

1. Open http://localhost:5173 in a browser.
2. Paste a Squads transaction ID (e.g. BtVmmpGqhvXgonCWU2DUb3mvyzDErFSi5MhZM8Qw5ium).
3. Click Decode to see:
   • Program name and ID
   • Accounts (named when available from IDL)
   • Decoded data (BN/hex normalized to readable strings)

API

• Decode a transaction:

curl "http://localhost:5173/api/decode/<TX_ID>"

Response shape:

{
  "transactionId": "<TX_ID>",
  "memo": "...",
  "instructions": [
    {
      "programId": "...",
      "programName": "...",
      "instructionName": "...",
      "accounts": [ { "name": "...", "address": "...", "index": 0 } ],
      "decodedData": { "...": "..." },
      "rawData": [1,2,3]
    }
  ]
}

Project structure

• server/index.js: Express server, serves public/ and GET /api/decode/:txId
• src/decoder.js: Core decoding (fetch Squads tx, resolve ALT accounts, decode via @coral-xyz/anchor)
• public/index.html: Simple UI for decoding and viewing results

Add more programs / IDLs

Known programs and IDL URLs live in PROGRAM_MAPPINGS inside src/decoder.js. Add entries like:

PROGRAM_MAPPINGS["YourProgramPubkeyHere"] = {
  name: "YOUR_PROGRAM",
  idlUrl: "https://raw.githubusercontent.com/your-org/your-repo/main/target/idl/your_program.json"
};

Restart the server afterward.

Configuration

• Port: PORT env var (default 5173).
• RPC endpoint: set inside src/decoder.js in the Connection constructor. Replace with your preferred endpoint if needed.

Troubleshooting

• Unknown program: add its ID and IDL URL to PROGRAM_MAPPINGS.
• Network/rate limits: the app calls Squads API, GitHub raw (for IDLs), and a Solana RPC. Use reliable endpoints or retry later.
• CORS: enabled on the server for the API.

Scripts

• npm run dev: Start with nodemon
• npm start: Start with node

License

MIT