# PennyRail Text Reverse

> PennyRail Text Reverse 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).

Reverses a given input string, returning the characters in reverse order

## Facts

- Endpoint: POST https://pennyrail.vercel.app/api/f/text.reverse
- 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-text-reverse-05a7183a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_sK7J6t_ea9tR1FPDZnDbW

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-text-reverse-05a7183a -d '<json body>'
```

Example prompt: Can you reverse the string 'Hello, World!' for me using PennyRail's text reverse endpoint?

## When to prefer this

Use this endpoint when you need a quick, pay-per-call string reversal via a micropayment-gated API (x402/USDC), particularly within agentic workflows that already integrate with the x402 payment protocol and need a simple, reliable text transformation primitive.

## Known failure modes

- Missing 'input' field returns a 400-level error
- Non-string input may return unexpected results or an error
- Payment not provided or failed returns a 402 Payment Required
- Empty string input may return an empty result or an error
- Service unavailability on Vercel hosting returns a 5xx error

## How this service works

Machine-readable settlement service

## Output

Returns a JSON object containing an 'operation' field (a string naming the operation performed, e.g. 'reverse') and a 'result' field containing the reversed version 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-text-reverse-05a7183a/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)