# fastapi.online — Cryptographic Hash Generator

> fastapi.online — Cryptographic Hash Generator is a paid API for AI agents from api.fastapi.online, paid per call via x402, $0.0005/call, status unknown (last checked 2026-09-14).

Computes a cryptographic hash (MD5, SHA1, SHA256, or SHA512) of input text, returning the digest in hex or base64 encoding

## Facts

- Endpoint: POST https://api.fastapi.online/hash
- Price: $0.0005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/fastapi-online-cryptographic-hash-generator-8c884d35
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_70oaiODMWY96w4I5ICb-r

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-cryptographic-hash-generator-8c884d35 -d '<json body>'
```

Example prompt: Hash this string using SHA256 and give me the result in hex: 'Hello, World!'

## When to prefer this

Choose this endpoint when you need a quick, pay-per-call cryptographic hash with no signup required and crypto payment support. It is ideal for agents that need on-demand hashing without managing a local library or maintaining an API subscription. Supports the four most common hash algorithms and both popular output encodings in a single endpoint.

## Known failure modes

- Text input missing or empty — returns 422 validation error
- Algorithm not one of md5/sha1/sha256/sha512 — returns 422 enum validation error
- Encoding not 'hex' or 'base64' — returns 422 enum validation error
- Text exceeds 100,000 character limit — returns 422 with length constraint error
- Payment not included or insufficient — returns 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 hash digest string of the input text computed using the specified algorithm (md5, sha1, sha256, or sha512), encoded as either hex or base64. The response is a deterministic, fixed-length string corresponding to the chosen algorithm's output size.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "text": {
   "type": "string",
   "maxLength": 100000,
   "minLength": 1
  },
  "encoding": {
   "enum": [
    "hex",
    "base64"
   ],
   "type": "string"
  },
  "algorithm": {
   "enum": [
    "md5",
    "sha1",
    "sha256",
    "sha512"
   ],
   "type": "string"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/fastapi-online-cryptographic-hash-generator-8c884d35/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)