# fastapi.online — Stablecoin Chains Lookup

> fastapi.online — Stablecoin Chains Lookup is a paid API for AI agents from api.fastapi.online, paid per call via x402, $0.001/call, status down (last checked 2026-10-12).

Returns a list of blockchain networks that support stablecoin payments (e.g. USDC) for the fastapi.online pay-per-call API

## Facts

- Endpoint: POST https://api.fastapi.online/stablecoin-chains?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: down
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/fastapi-online-stablecoin-chains-lookup-be5fac11
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_-hZiqsuvUI0PU3AAFxm1l

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-stablecoin-chains-lookup-be5fac11 -d '<json body>'
```

Example prompt: What blockchain networks support stablecoin payments on fastapi.online so I can figure out which chain to use for paying per call?

## When to prefer this

Use this endpoint when you need to programmatically discover which blockchain networks are accepted for stablecoin payment before making inference calls on fastapi.online. Prefer this over hardcoding chain assumptions, especially if you need to dynamically select or validate a payment chain at runtime.

## Known failure modes

- Empty or null response if no chains are configured
- HTTP 402 if payment not provided before calling
- HTTP 500 if the backend service is unavailable
- Malformed JSON if the server is under load or misconfigured

## 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

A list of blockchain networks (chains) on which stablecoin payments (e.g. USDC) are accepted for accessing the fastapi.online pay-per-call API, including chain names and/or identifiers.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "required": [],
     "properties": {}
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/fastapi-online-stablecoin-chains-lookup-be5fac11/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)