CRX API

The relayer's HTTP API brokers quotes, prices margin, and serves the registries. It is the only off-chain service a client calls to quote and bind. The questions below cover the base URL, auth, every endpoint, the trade flow, errors, and limits.

What is the CRX API?

The CRX API is the relayer's HTTP API. It brokers requests for quote, prices margin, and serves the public maker and taker registries. It is the only off-chain service a client calls to quote and bind a trade. The relayer never takes custody; the binding happens on-chain, between the client and CRX.

What is the base URL?

The relayer base URL is read from NEXT_PUBLIC_RELAYER_URL. The table below shows the value per environment.

The production relayer is served same-origin behind nginx (the /svc/relayer path-prefix on app.crxfx.com), which means browser calls require no CORS handling and no Local Network Access prompt. All paths below are relative to the base. Try a call now using the following command:

curl https://app.crxfx.com/svc/relayer/health
# {"status":"ok"}

Or run it here: edit the inputs, press Try It, and read the live response. Every endpoint in the API Reference has its own page with a panel like the following:

GET/health
Relayer liveness. The simplest live call. No params, no token.
No parameters.
Bearer token · optional
Bearer
LanguagecURLNodePythonCopy
curl -X GET "https://app.crxfx.com/svc/relayer/health"
Try It!
Response
Press Try It! to run the call and read the live response.

How does authentication work?

Authentication takes two POST calls: a challenge, then a login. The login returns a JWT valid for one hour. Some reads are public and need no token.

• signature is a personal_sign over the exact message from step 1.
• Send the token as Authorization: Bearer <token> on every authenticated call.
• expires_at is a Unix timestamp (seconds). The token is valid for ~1 hour.

NoteThe trade path itself needs no session. Quoting and binding are authorized by the two EIP-712 Terms signatures, not by a JWT. Auth gates the maker's inbox and RFQ writes, not the bind.

Both steps are live in the reference: POST /auth/challenge and POST /auth/login.

What are the core endpoints?

The table below shows the complete relayer set; each endpoint has its own page in the API Reference with a live Try-It panel. In the table, auth means a Bearer token is required, and write means the call changes live network state.

What is the trade flow, end to end?

A single trade calls the endpoints in the following order.

1. Taker POST /rfq → { rfq_id }.
2. Maker GET /rfq/inbox → sees the RFQ.
3. Maker POST /rfq/:id/quote → relayer returns canonical Terms.
4. Maker POST /rfq/:id/confirm with an EIP-712 signature over Terms.
5. Taker GET /rfq/:id/bundle → the dual-signed bundle, once anchored.
6. Taker submits the bundle on-chain to bind. The position is live.

The concept behind the sequence is explained in Request for Quote (~2 min).

What do errors look like?

Every error is one JSON shape, { "error": "<message>" }, with the HTTP status carrying the class. The table below shows the meaning of each status.

What are the rate limits?

One limit exists: 100 RFQ submissions per firm per minute (a 60-second sliding window) on POST /rfq. If the caller exceeds it, the relayer returns 429. No other endpoint is limited.

No mandated poll interval. For reference, the relayer's own chain discovery runs every 30 s and margin quotes are cached for 30 s. Polling /margin faster than that returns no fresher data. Bundle polling after a quote is the exception: poll every second or two, because the anchor confirms in seconds.

Is there an SDK?

The CRX integration surface is the REST API plus direct chain reads; there is no separate package to install or version. Call this API directly with fetch (the examples above are the whole pattern) and read the chain over RPC with any EVM client (viem, ethers, web3.py, cast) against Base Sepolia (chain id 84532).

There is no installable CRX SDK. The closest thing to a typed client is the endpoint registry, frontend/lib/developers/endpoints.ts: the one description of every relayer route the browser calls (method, path, auth, write, fields, sample response). It drives the API explorer and the live crx-try panels, leaving it unable to drift from the running service. Read it as the contract.

For on-chain read shapes, see Positions & Settlement API (~3 min). For contract addresses, see Live deployments (~1 min).