# fastapi.online — Crypto Orderbook Lookup

> fastapi.online — Crypto Orderbook Lookup is a paid API for AI agents from api.fastapi.online, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-11).

Returns the current order book (bids and asks) for a given trading symbol, with optional depth limit

## Facts

- Endpoint: POST https://api.fastapi.online/orderbook?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/fastapi-online-crypto-orderbook-lookup-a3449682
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_UI1HWxFimkPodPLc8ijd7

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability fastapi-online-crypto-orderbook-lookup-a3449682 -d '<json body>'
```

Example prompt: Can you fetch the order book for BTC/USDT and show me the top 20 bids and asks right now?

## When to prefer this

Choose this endpoint when you need a quick, pay-per-call order book snapshot for a crypto trading pair without signing up for a full exchange API. Ideal for agents that occasionally need market depth data and want to pay in USDC with no subscription commitment.

## Known failure modes

- Invalid or unrecognized symbol returns an error or empty result
- Limit parameter out of accepted range may cause a validation error
- Service unavailability or timeout returns a 5xx error
- Missing required symbol field may result in a 422 Unprocessable Entity
- Payment failure via x402 protocol returns a 402 Payment Required

## How this service works

Chat, embeddings, OCR, speech-to-text, image editing, image understanding (captioning/Q&amp;A), text-to-speech, translation, writing tools, classification tools, developer tools, local utilities, format/checksum validators, encoding &amp; crypto utilities, date/time calculators, geo/coordinate math, math &amp; finance calculators, novelty tools, and business/social writing generators — 179 endpoints in all, across multiple specialized self-hosted models. Pay per call with crypto — no signup — or get an API key.

## Output

Returns a snapshot of the current order book for the requested trading symbol, including arrays of bids and asks at various price levels with their corresponding quantities, up to the specified depth limit.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "limit": {
   "type": "string"
  },
  "symbol": {
   "type": "string"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/fastapi-online-crypto-orderbook-lookup-a3449682/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.fastapi.online](https://www.zero.xyz/host/api.fastapi.online/llms.txt)