# ONE Engine Array Difference

> ONE Engine Array Difference is a paid API for AI agents from one-search.one-engine.workers.dev, paid per call via x402, $0.0005/call, status unknown (last checked 2026-10-24).

Returns the set difference between two arrays, yielding elements in the first array that are not present in the second (comparison) array.

## Facts

- Endpoint: POST https://one-search.one-engine.workers.dev/v3/array/difference/t1?utm_source=zero.xyz
- Price: $0.0005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-24
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/one-engine-array-difference-9e9f59b5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_9ODkJL7LNjASMIT7QVQZA

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 one-engine-array-difference-9e9f59b5 -d '<json body>'
```

Example prompt: I have two lists of product IDs — [101, 202, 303, 404, 505] and [202, 404] — can you find which IDs from the first list are NOT in the second list?

## When to prefer this

Use this endpoint when an autonomous agent needs a fast, cheap, stateless computation to find the set difference between two arrays without spinning up local logic. Ideal for agentic pipelines on Base that already use x402 micropayments, where the per-call cost ($0.0005 USDC) is negligible and offloading array math keeps agent code simple. Prefer this over local computation when working in constrained runtime environments or when the operation needs to be auditable as a paid API call.

## Known failure modes

- Array exceeds 1000 items — request rejected
- Malformed JSON array in `values` or `other` — validation error
- Missing required `values` field — 400 Bad Request
- Payment not included or insufficient — 402 Payment Required
- Cloudflare Worker cold start or timeout — 503 or timeout error

## How this service works

Low-cost pay-per-call utility APIs for autonomous agents using x402 on Base.

## Output

A JSON object containing an array of elements that appear in the primary `values` array but not in the `other` comparison array, representing the set-theoretic difference A \ B.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "values"
 ],
 "properties": {
  "size": {
   "type": "integer"
  },
  "other": {
   "type": "array",
   "description": "Optional comparison array"
  },
  "offset": {
   "type": "integer"
  },
  "values": {
   "type": "array",
   "description": "JSON array with at most 1000 items"
  }
 }
}
```

## Response schema (JSON Schema)

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

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/one-engine-array-difference-9e9f59b5/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from one-search.one-engine.workers.dev](https://www.zero.xyz/host/one-search.one-engine.workers.dev/llms.txt)