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This guide walks you through making your first Relayer API call. You will verify connectivity with the health endpoint, then make an authenticated request.

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Prerequisites

  • An API key from your operator dashboard (see Authentication)
  • curl or Node.js installed

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Environments

Relayer provides two environments. Choose the one that matches your stage:
EnvironmentBase URLUse for
Sandboxhttps://testnet.relayer.fi/v1Testing and development
Productionhttps://api.relayer.fi/v1Live operations
Sandbox runs on Render — the first request after idle may take 30-60 seconds to cold-start.

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Step 1: Verify connectivity

Start with the unauthenticated root endpoint to confirm the API is reachable. 
curl https://testnet.relayer.fi/v1/
You should receive a 200 with a basic service descriptor.

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Step 2: Set up your environment

Store your API key and base URL as environment variables: 
export RELAYER_BASE_URL="https://testnet.relayer.fi/v1"
export RELAYER_API_KEY="rk_client_key_v1_your_key_here"

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Step 3: Make an authenticated request

Now make an authenticated call. This example lists the wallets in your workspace — a safe, read-only operation that confirms auth, scope, and module activation in one go. 
curl -X GET $RELAYER_BASE_URL/signing/wallets \
  -H "Authorization: ApiKey $RELAYER_API_KEY" \
  -H "Content-Type: application/json"
A successful response looks like: 
{
  "success": true,
  "message": "Wallets retrieved",
  "data": [],
  "statusCode": 200,
  "timestamp": "2026-05-15T12:00:00.000Z",
  "path": "/v1/signing/wallets"
}
An empty data array is expected on a fresh workspace. It means the API authenticated your request successfully — you just haven’t created any wallets yet.

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Step 4: Explore the Kits

Now that you are authenticated, explore the Kit that matches your use case:

Signing Kit

Create self-custodial wallets and sign transactions with passkeys.

Payout Kit

Set up fiat on/off-ramp rails and manage recipients.

Agent Kit

Ship budget-enforced AI agents that can sign and pay for resources.

Widget Kit

Embed canonical swap, transfer, and crosschain widgets in your app.

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Troubleshooting

ProblemSolution
Connection refusedCheck RELAYER_BASE_URL — sandbox: https://testnet.relayer.fi/v1, production: https://api.relayer.fi/v1
401 UnauthorizedVerify your Authorization header uses ApiKey prefix (not Bearer)
404 Not FoundCheck the endpoint path starts with /v1/
Slow first responseSandbox cold-starts after idle (30-60s). Production does not have this delay.