Developers # A few lines on your server. SDKs for TypeScript, Go, Rust and Python, and a REST API. Pay for your users, or send from your own wallets. Read the quickstart API reference Building an AI agent? Start here → ## The same few lines, in your language Sponsor key Your server · sponsor key Own key Your agent · own key send.ts TypeScript Go Rust Python Your server · sponsor key in TypeScript ` import { createHash } from 'node:crypto'; import { CoRelayerClient, type RelayRequest } from '@corelayer/sdk'; // On your server. The sponsor key never reaches a browser. const apiKey = process.env.CORELAYER_API_KEY; if (!apiKey) throw new Error('Set CORELAYER_API_KEY'); const corelayer = new CoRelayerClient({ baseUrl: 'https://api.co-relayer.com', apiKey, }); // Your user signed the transaction. Your plan pays the network fee. export async function payForUser(req: RelayRequest, actionId: string) { const key = createHash('sha256').update(actionId).digest('hex'); const { data } = await corelayer.relay(req, { intentKey: key }); return data.txHash; } ` - Your app signs the transaction for your user. - Your server sends it with your sponsor key. - Your plan covers the network fee. - TypeScript - Go - Rust - Python 01 · Integration ## Pick your path - Sponsor key ### Sponsor your users Your server relays each signed transaction with a sponsor key. One key covers every wallet your app runs. Builder and up. - Your own key ### Send from keys your code holds A key your program holds, or wallets you name on your plan. Sign once and relay. Every plan. - AI agents ### Quickstart for an agent Your agent discovers, prices, pays and relays with its own key. ## For agents and tools - llms.txt - pricing.json - corelayer.json - security.txt 02 · Guides ## Recipes Short guides for the jobs you’ll do most. - ### Sponsor your users Send your users’ signed transactions from your server with one sponsor key. - ### Sign and relay Sign once with your own key or a wallet you name, then send it. - ### Check your quota See how many transactions your plan has left before you send. - ### Handle a re-sign What to do on the rare day a transaction needs one more signature. - ### Watch a transaction Follow each transaction from your request to its result on chain. - ### Verify a relayer Check on chain that the relayer you were given is on the list. 03 · Reference ## API and tools - ### OpenAPI document Every route, typed. - ### Error catalogue Every error code, with what to do next. - ### MCP server Read prices, network status, relayers and your quota as MCP tools. - ### x402 Buy a plan or top up credits inside an HTTP 402 exchange. - ### Drop-in endpoints Already on another agent relayer kit? Change one base URL. - ### Changelog What changed, and when. Changelog feed Get started ## Start with the wallet you have Connect a MultiversX wallet and pay a plan in USDC. Buying your plan is already a gasless transaction. Get started Read the docs Building an AI agent? Start here → Questions? support@co-relayer.com