# ONE Engine Array Flatten (T4)

> ONE Engine Array Flatten (T4) is a paid API for AI agents from one-search.one-engine.workers.dev, paid per call via x402, $0.0015/call, status unknown (last checked 2026-10-02).

Flattens a nested JSON array into a single-level array, with optional comparison and offset parameters.

## Facts

- Endpoint: POST https://one-search.one-engine.workers.dev/v3/array/flatten/t4?utm_source=zero.xyz
- Price: $0.0015/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/one-engine-array-flatten-t4-c8e090ce
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_JK8QnBkK3Ae3lez9yReQF

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-flatten-t4-c8e090ce -d '<json body>'
```

Example prompt: Flatten this nested JSON array for me — it has up to 500 items and I want the result starting at offset 10: [[1,2],[3,[4,5]],6].

## When to prefer this

Choose this endpoint when you need a cheap, pay-per-call utility to flatten nested JSON arrays at low cost ($0.0015 USDC) without standing up your own infrastructure. Ideal for autonomous agents that occasionally need to normalize array structures mid-workflow without a persistent backend dependency.

## Known failure modes

- Input array exceeds 1000-item limit — request rejected or truncated
- Malformed JSON in values field — 400 error
- Invalid offset value (negative or out of bounds) — may return empty or error
- Non-array value passed as 'values' field — schema validation error
- Payment failure via x402 — 402 response before processing begins

## How this service works

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

## Output

A JSON object containing the flattened (single-level) version of the input array, with any nested sub-arrays collapsed into a single sequence, optionally offset and compared against a provided reference array.

## 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-flatten-t4-c8e090ce/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)