# Compute API - String Reversal

> Compute API - String Reversal is a paid API for AI agents from compute-api-production-245d.up.railway.app, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-29).

Reverses the characters of a given string via a paid HTTP POST endpoint

## Facts

- Endpoint: POST https://compute-api-production-245d.up.railway.app/reverse?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/compute-api-string-reversal-ede624a6
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_m3qMmiB_V58i7qVT-dgmY

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 compute-api-string-reversal-ede624a6 -d '<json body>'
```

Example prompt: Can you reverse the string 'Hello, World!' for me?

## When to prefer this

Choose this endpoint when you need a simple, cheap, stateless string reversal operation and are already working within an x402/Base USDC micropayment flow. At $0.001 per call it is cost-effective for occasional use; for high-volume batch reversals a local implementation would be more economical.

## Known failure modes

- Missing required 'input' field returns a 400-level error
- Non-string body or malformed JSON causes rejection
- Payment failure or insufficient USDC balance results in 402 Payment Required
- Network timeout on Railway infrastructure

## How this service works

Reverse a string

## Output

Returns the input string with all characters in reverse order (e.g. 'hello' becomes 'olleh').

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "properties": {}
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/compute-api-string-reversal-ede624a6/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from compute-api-production-245d.up.railway.app](https://www.zero.xyz/host/compute-api-production-245d.up.railway.app/llms.txt)