# JSON URL Fields Check

> JSON URL Fields Check 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).

Validates selected fields in a JSON object to confirm they contain absolute HTTP or HTTPS URLs, returning counts, normalized values, and a versioned validation result.

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/json-url-fields-check
- 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-url-fields-check-5c36ea03
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_aGjEI3nb5Ir4rJSP7uUPC

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-url-fields-check-5c36ea03 -d '<json body>'
```

Example prompt: Before I hand this JSON payload off to the downstream service, can you check whether the fields 'homepage', 'avatar_url', and 'callback' all contain valid absolute HTTP or HTTPS URLs? Here's the object: {"homepage": "https://example.com", "avatar_url": "ftp://files.example.com/img.png", "callback": "not-a-url"}.

## When to prefer this

Choose this endpoint when you need a deterministic, versioned, in-memory URL shape validation for specific named fields within a JSON object — particularly before handing structured data or a batch plan to a downstream tool with a strict URL contract. Prefer this over a general URL reachability checker (like Delx Url Health) when you only need format/shape validation without making an outbound network request to the URL. Prefer this over writing custom regex logic when you want a versioned, auditable contract result.

## Known failure modes

- Field name not found in the provided object — reported as missing or null in findings
- Field value is not a string — flagged as invalid URL shape
- URL uses a non-HTTP/HTTPS scheme (e.g. ftp://, mailto:) — fails the absolute HTTP/HTTPS check
- Empty or null field values — counted as failures in the result
- Exceeding 256 items in the fields array or 128 properties in the object — may result in request rejection
- Malformed input schema (non-object body) — likely returns a 4xx error

## How this service works

JSON URL Fields Check: JSON URL Fields Check checks selected fields for absolute HTTP or HTTPS URL shape from bounded caller-supplied values without an external provider. Call JSON URL Fields Check 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 URL Fields Check as versioned deterministic JSON. Price: $0.001 USDC v…

## Output

Returns a versioned deterministic JSON document containing: a pass/fail finding per checked field indicating whether the value matches absolute HTTP or HTTPS URL shape, counts of passing and failing fields, normalized URL values where applicable, and a versioned result contract identifier for downstream contract compliance.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "fields": {
   "type": "array",
   "items": {
    "type": "string",
    "maxLength": 8192
   },
   "maxItems": 256,
   "description": "Fields supplied to JSON URL Fields Check; used only for this bounded calculation and processed in memory without retention."
  },
  "object": {
   "type": "object",
   "description": "Object supplied to JSON URL Fields Check; used only for this bounded calculation and processed in memory without retention.",
   "maxProperties": 128,
   "additionalProperties": true
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "passed": true,
   "invalid_fields": []
  },
  "schema": "delx/util-json-url-fields-check/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "cb4e55880f0341cb1fa757a2bd29ae91f897ab40c9252e096c640684ad990ba9",
   "external_calls": 0
  },
  "operation": "data_batch:json_url_fields_check"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/json-url-fields-check-5c36ea03/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)