# PennyRail Text Reversal

> PennyRail Text Reversal is a paid API for AI agents from pennyrail.vercel.app, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Reverses the characters of an input string, returning it backwards

## Facts

- Endpoint: POST https://pennyrail.vercel.app/api/p/nano/text.reverse--string-backwards
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/pennyrail-text-reversal-7875689b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_TpwpynxCHf0O-mrB17Aao

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-reversal-7875689b -d '<json body>'
```

Example prompt: Can you reverse the string 'Hello, World!' so it reads backwards character by character?

## When to prefer this

Use this endpoint when you need a simple, reliable, pay-per-call string reversal without deploying your own infrastructure. Ideal for agents that occasionally need text reversal as a micro-utility and want to avoid maintaining custom code. Not appropriate for bulk/batch processing of many strings at once due to per-call cost.

## Known failure modes

- Missing 'input' field returns a validation error
- Non-string input may cause a type error
- Empty string input may return empty string or an error
- Payment failure (402) if USDC balance is insufficient or x402 header is missing

## How this service works

Machine-readable settlement service

## Output

Returns an object containing the reversed version of the input string, with all characters in reverse order from the original.

## 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-text-reversal-7875689b/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)