# URL Query Param Diff

> URL Query Param Diff 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).

Compares two URLs and returns added, removed, and changed query parameters between them as deterministic JSON.

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/url-query-param-diff
- 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/url-query-param-diff-4e586064
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_yvIeQiWVQEeqznteLREwy

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 url-query-param-diff-4e586064 -d '<json body>'
```

Example prompt: Can you diff the query parameters between these two URLs and tell me what was added, removed, or changed? Before: 'https://example.com/cb?code=abc&state=xyz' and after: 'https://example.com/cb?code=abc&state=xyz&extra=injected'

## When to prefer this

Choose this endpoint when you need a stateless, deterministic, zero-retention comparison of query parameters between two URLs — especially before accepting, caching, redirecting, or retrying a caller-supplied web response. Prefer it over manual string parsing when you need a structured, versioned JSON result with explicit pass/advisory status for downstream decision-making, and when you cannot rely on external dependencies or state.

## Known failure modes

- Malformed or unparseable URL input returns an error or advisory status
- URLs exceeding 8192 characters are rejected
- Missing before_url or after_url fields result in a validation error
- URLs with no query parameters produce an empty diff with pass status

## How this service works

URL Query Param Diff: URL Query Param Diff finds added, removed, and changed query parameters between URLs from bounded caller-supplied values without an external provider. Call URL Query Param Diff before accepting, caching, redirecting, or retrying a caller-supplied web response. Returns normalized web evidence, the computed finding, and an explicit pass or advisory status for URL Query Param Diff as versioned deterministic JSON. Price: $0.001 USDC via x402 on Base. First-party, stateless, me…

## Output

Returns versioned deterministic JSON containing: the normalized before and after URLs as web evidence, a computed finding listing added, removed, and changed query parameters with their values, and an explicit pass or advisory status indicating whether differences were detected.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "after_url": {
   "type": "string",
   "maxLength": 8192,
   "description": "After URL supplied to URL Query Param Diff; used only for this bounded calculation and processed in memory without retention."
  },
  "before_url": {
   "type": "string",
   "maxLength": 8192,
   "description": "Before URL supplied to URL Query Param Diff; used only for this bounded calculation and processed in memory without retention."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "added": {
    "c": "3"
   },
   "changed": {
    "a": {
     "after": "2",
     "before": "1"
    }
   },
   "removed": {
    "b": "2"
   }
  },
  "schema": "delx/util-url-query-param-diff/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "3515f5558fb69829367b6de74545ae835dc31d8214a47050a271c62c654bddfe",
   "external_calls": 0
  },
  "operation": "web_reliability:url_query_param_diff"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/url-query-param-diff-4e586064/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)