API Reference

Base URL: https://api.sequencemkts.com

Interactive Swagger UI: api.sequencemkts.com/docs (browse without auth).

Endpoints

Authentication

Every request needs a Bearer token:

curl https://api.sequencemkts.com/v1/health \
  -H "Authorization: Bearer seq_live_YOUR_API_KEY"

API keys start with seq_live_ (production) or seq_test_ (sandbox). Get yours from Settings → API Keys in the Terminal.

Sandbox keys return live market data but simulate order fills — useful for testing without risking real money.

Data encoding

Sequence uses fixed-point integers for financial values to avoid float precision errors. Every numeric field is suffixed with its scale:

If a field has no suffix (e.g. bid_price), it's a human-readable float. Rule: suffix = fixed-point integer, no suffix = float.

Request format

• All request and response bodies are JSON (UTF-8).
• HTTPS only — plain HTTP is rejected.
• Content-Type: application/json required on POST / PATCH / PUT.

Request ID

Every request gets a correlation ID:

• Send your own: X-Request-Id: your-id (≤128 chars).
• Or let the server generate a UUID v4.
• Echoed back in the response X-Request-Id header.

Idempotency

Order submissions are idempotent via graph_id. Submit the same graph_id twice → second request returns the original order's node_order_id without creating a duplicate. Safe retries — on timeout or 5xx, retry with the same graph_id and you'll never double-submit.

If you retry with the same graph_id but different parameters, you get 409 Conflict.

Errors

All errors return a structured JSON envelope:

{
  "error": {
    "code": "VALIDATION_ERROR",
    "message": "validation error: qty_1e8: must be positive",
    "request_id": "550e8400-e29b-41d4-a716-446655440000",
    "details": [
      { "field": "qty_1e8", "message": "must be positive" }
    ]
  }
}

code is stable and safe for programmatic handling. message is human-readable. details is only present for VALIDATION_ERROR.

Rate limits

Each API key has a requests-per-second limit on your account profile. Exceeding it returns 429. The limit applies across all REST endpoints.

The limiter is a token bucket: bucket capacity = 2× your qps (so an idle key can absorb a brief burst), refill = qps tokens/sec. Default tier-by-tier:

Each API key has its own bucket — keys do not share quota. Buckets do not share across IPs either; rate limiting is keyed on the authenticated client_id, not on source IP.

SSE and WebSocket connections are long-lived and don't count against the rate limit after the initial connection. WebSockets use a short-lived ticket: POST /v1/ws/ticket for a one-time token, then pass it as a query parameter on the WS upgrade.

See Rate Limits for headers and retry strategies.

Venue health & drift detection

Public endpoint (no auth). Compares an operator-configured set of expected venues against the venues currently connected via cc-link (local + peer-link mirrored). Designed for external monitors / status pages — point any HTTP probe at it on a 60-second interval and alert on drift == true.

Response

{
  "expected": ["binance","bybit","coinbase","cryptocom","dex","hyperliquid","kalshi","kraken","okx","polymarket","solana","binance-perp","bybit-perp","okx-perp","bitget"],
  "connected": ["binance","binance-perp","bitget","bybit","bybit-perp","coinbase","cryptocom","dex","hyperliquid","kalshi","kraken","okx","okx-perp","polymarket","solana"],
  "missing": [],
  "extra": [],
  "drift": false
}

For the per-edge view (region, connected venues, symbol counts), use /v1/edges (auth required).

Quick example

Full workflow in curl — quote, submit, check:

# 1. Get quote for ETH-USD
curl https://api.sequencemkts.com/v1/quotes/ETH-USD \
  -H "Authorization: Bearer $SEQ_API_KEY"
 
# 2. Submit a market buy for 1 ETH
curl -X POST https://api.sequencemkts.com/v1/orders \
  -H "Authorization: Bearer $SEQ_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"symbol": "ETH-USD", "side": "buy", "qty": 1.0}'
 
# 3. Check the graph status
curl https://api.sequencemkts.com/v1/execution_graphs/graph_YOUR_ID \
  -H "Authorization: Bearer $SEQ_API_KEY"

For SDK examples (Python, Rust, CLI), see the Quick Start.