# Agent402 UK JSON Diff

> Agent402 UK JSON Diff is a paid API for AI agents from agent402.co.uk, paid per call via x402, $0.001/call, status down (last checked 2026-09-15).

Computes a structural diff between two JSON objects, returning added, removed, and changed paths.

## Facts

- Endpoint: POST https://agent402.co.uk/v1/utils/json/diff
- Price: $0.001/call
- Payment: x402
- Status: down
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agent402-uk-json-diff-e1b087eb
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_FbBviCAvDvUR3YeIzdNQ0

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 agent402-uk-json-diff-e1b087eb -d '<json body>'
```

Example prompt: Compare these two JSON objects and tell me exactly what was added, removed, or changed — the 'before' is {"status":"pending","amount":100} and the 'after' is {"status":"complete","amount":100,"receipt":"abc123"}.

## When to prefer this

Use this endpoint when you need a fast, precise structural diff between two JSON objects without writing custom comparison logic — ideal for mid-task state comparison in agentic workflows, configuration drift detection, or API response regression checks. Prefer it over manual comparison or general-purpose code execution when you need a clean list of added/removed/changed paths in a single lightweight call.

## Known failure modes

- Non-object inputs (arrays or primitives instead of objects) may be rejected or produce unexpected results
- Deeply nested or very large JSON objects may hit payload size limits
- Malformed JSON syntax in either input will return a validation error
- Missing 'a' or 'b' fields in the request body will cause an error

## How this service works

Don't burn tokens on deterministic work. Go/no-go jobs first: payout preflight, text firewall (PII/secrets), budget check — then rails, calendars, finmath. x402 USDC on Base. UK + global. agent402.co.uk — not agent402.tools. $0.001–$0.002 USDC on Base. No API keys.

## Output

A structured JSON diff report listing the paths that were added in B but not A, paths removed from A that are absent in B, and paths where values changed between A and B, enabling precise identification of structural mutations between two JSON states.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "a": {
   "type": "object",
   "description": "Left value"
  },
  "b": {
   "type": "object",
   "description": "Right value"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "added": [
   "y"
  ],
  "equal": false,
  "changed": [
   {
    "to": 2,
    "from": 1,
    "path": "x"
   }
  ],
  "removed": []
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agent402-uk-json-diff-e1b087eb/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agent402.co.uk](https://www.zero.xyz/host/agent402.co.uk/llms.txt)