# JSON Array Filter Keys

> JSON Array Filter Keys is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-15).

Filters rows in a JSON object array, keeping only objects whose specified key matches one of a set of allowed values

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/json-array-filter-keys
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/json-array-filter-keys-dc9c53e6
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_7PrRq1BvuqZnFh0IQ9bZo

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 json-array-filter-keys-dc9c53e6 -d '<json body>'
```

Example prompt: Filter this array of product records to only keep rows where the 'status' key matches 'active' or 'pending': [{"id":1,"status":"active"},{"id":2,"status":"archived"},{"id":3,"status":"pending"}]

## When to prefer this

Use this endpoint when an agent needs a deterministic, in-memory, stateless key-based whitelist filter on a JSON object array before passing structured data to a downstream tool with a stricter schema contract. Prefer it over general-purpose code execution when you need a versioned, reproducible result with counts and no side effects, and when the dataset fits within 256 rows.

## Known failure modes

- Key not found in any object — returns empty filtered array with zero match count
- Items array exceeds 256 objects — request rejected with validation error
- Allowed list exceeds 256 entries — request rejected
- Key string exceeds 8192 characters — request rejected
- Malformed input JSON — returns schema validation error
- Empty allowed list — returns empty array

## How this service works

JSON Array Filter Keys: JSON Array Filter Keys keeps object rows whose selected key matches caller values from bounded caller-supplied values without an external provider. Call JSON Array Filter Keys before an agent hands structured data or a batch plan to a downstream tool with a stricter contract. Returns the bounded transformation or validation finding with counts, normalized values, and a versioned result contract for JSON Array Filter Keys as versioned deterministic JSON. Price: $0.001 USD…

## Output

Returns a versioned deterministic JSON object containing the filtered array (only rows whose specified key matched an allowed value), row counts for total input and matched output, normalized values, and a versioned result contract for downstream compatibility.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "key": {
   "type": "string",
   "maxLength": 8192,
   "description": "Key supplied to JSON Array Filter Keys; used only for this bounded calculation and processed in memory without retention."
  },
  "items": {
   "type": "array",
   "items": {
    "type": "object",
    "maxProperties": 128,
    "additionalProperties": true
   },
   "maxItems": 256,
   "description": "Items supplied to JSON Array Filter Keys; used only for this bounded calculation and processed in memory without retention."
  },
  "allowed": {
   "type": "array",
   "items": {
    "type": "string",
    "maxLength": 8192
   },
   "maxItems": 256,
   "description": "Allowed supplied to JSON Array Filter Keys; used only for this bounded calculation and processed in memory without retention."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "items": [
    {
     "id": 1,
     "status": "ok"
    }
   ],
   "matched_count": 1
  },
  "schema": "delx/util-json-array-filter-keys/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "c1b64d403dd4df4223045c843cca745575ec8fc78aca3b171b5d12f60601eb75",
   "external_calls": 0
  },
  "operation": "data_batch:json_array_filter_keys"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/json-array-filter-keys-dc9c53e6/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.delx.ai](https://www.zero.xyz/host/api.delx.ai/llms.txt)