# SHA-256 Digest as Base64URL from Hex Bytes

> SHA-256 Digest as Base64URL from Hex Bytes is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-02).

Computes a SHA-256 hash of raw bytes provided as a hex string and returns the digest encoded as base64url

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/digest-sha256-base64url-rawhex?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/sha-256-digest-as-base64url-from-hex-bytes-f258ba33
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_eOvD5sBzISiR8ZDYWMBO3

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 sha-256-digest-as-base64url-from-hex-bytes-f258ba33 -d '<json body>'
```

Example prompt: Can you compute the SHA-256 hash of these hex bytes — 48656c6c6f — and give me the result encoded as base64url?

## When to prefer this

Use this endpoint when you need a SHA-256 hash specifically of raw bytes supplied as a hex-encoded string and want the result in base64url encoding — a combination particularly common in JWT, JOSE, and modern cryptographic protocols. Prefer the free sandbox POST /v1/sandbox/digest-sha256-base64url-rawhex when available to avoid the $0.003 USDC cost. Choose this paid endpoint when the sandbox is unavailable or rate-limited.

## Known failure modes

- Invalid hex string (odd length or non-hex characters) — returns an error indicating malformed input
- Input text or key exceeds maximum length of 512 or 100,000 characters respectively — rejected with validation error
- Payment of $0.003 USDC not provided or payment fails — 402 Payment Required response
- Empty input string — rejected due to minLength:1 constraint

## How this service works

Call when an agent needs a sha256 digest of hex bytes, encoded as base64url. Exact $0.003 USDC. Prefer unpaid POST /v1/sandbox/digest-sha256-base64url-rawhex first.

## Output

Returns a SHA-256 digest of the input raw bytes (provided as a hex string), encoded using the base64url alphabet (URL-safe base64 without padding issues). The response contains the digest string ready for use in cryptographic contexts such as signing, integrity verification, or fingerprinting.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "key": {
   "type": "string",
   "maxLength": 512,
   "minLength": 1,
   "description": "HMAC secret. Required on HMAC SKUs. Omit it for plain digests and checksums. The key is not stored."
  },
  "text": {
   "type": "string",
   "examples": [
    "68656c6c6f"
   ],
   "maxLength": 100000,
   "minLength": 1,
   "description": "Message to digest. For raw-hex SKUs this is hex bytes; for utf16 or latin1 SKUs it is decoded with that encoding. Otherwise it is UTF-8 text."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/sha-256-digest-as-base64url-from-hex-bytes-f258ba33/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agentshelf.syntexa.ch](https://www.zero.xyz/host/agentshelf.syntexa.ch/llms.txt)