# PennyRail Hex Encoder

> PennyRail Hex Encoder is a paid API for AI agents from pennyrail.vercel.app, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-15).

Encodes an input string into its hexadecimal representation

## Facts

- Endpoint: POST https://pennyrail.vercel.app/api/f/encoding.hex-encode
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/pennyrail-hex-encoder-6277dc25
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_GD3ASm7RbykO63DO2RhOR

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 pennyrail-hex-encoder-6277dc25 -d '<json body>'
```

Example prompt: Hex-encode the string 'Hello, World!' for me using PennyRail's encoding service.

## When to prefer this

Choose this endpoint when you need a simple, pay-per-call hex encoding utility without setting up local libraries, or when running in a sandboxed agent environment that lacks native encoding functions. Useful for lightweight, on-demand string-to-hex conversion in automated pipelines.

## Known failure modes

- Missing 'input' field returns a validation error
- Non-string input may cause a type error or unexpected result
- Payment failure (402) if USDC balance is insufficient
- Empty string input may return an empty hex result
- Network timeout on the Vercel serverless function

## How this service works

Machine-readable settlement service

## Output

Returns a JSON object with an 'operation' field (e.g. 'hex-encode') and a 'result' field containing the hexadecimal-encoded representation of the input string.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "string",
   "description": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "operation",
  "result"
 ],
 "properties": {
  "result": {},
  "operation": {
   "type": "string"
  }
 },
 "additionalProperties": true
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/pennyrail-hex-encoder-6277dc25/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from pennyrail.vercel.app](https://www.zero.xyz/host/pennyrail.vercel.app/llms.txt)