# PennyRail Hex Encode

> PennyRail Hex Encode 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 via a paid API endpoint

## Facts

- Endpoint: POST https://pennyrail.vercel.app/api/p/nano/encoding.hex-encode--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-encode-013f85e3
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_lixcPzzN4PoAVyfZdavrD

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-encode-013f85e3 -d '<json body>'
```

Example prompt: Can you hex-encode the string 'Hello, World!' for me using PennyRail?

## When to prefer this

Choose this endpoint when you need a simple, on-demand hex encoding step within an automated pipeline and are already operating in an x402 micropayment context. It is best suited for agents that need to encode small strings or values programmatically without standing up their own encoding library, or when hex encoding is one step in a larger PennyRail workflow.

## Known failure modes

- Missing required 'input' field returns a 400 or validation error
- Payment failure (402) if x402 payment header is not provided or insufficient funds
- Empty string input may return empty hex or an error depending on implementation
- Non-UTF-8 or binary input passed as a JSON string may cause encoding errors
- Service unavailability on Vercel cold starts may cause latency spikes or 503 errors

## How this service works

Machine-readable settlement service

## Output

Returns a JSON object containing the hex-encoded representation of the provided input string, suitable for downstream use in encoding pipelines, debugging, or data transmission.

## Request schema (JSON Schema)

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

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "additionalProperties": true
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/pennyrail-hex-encode-013f85e3/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)