# Redirect Chain Check

> Redirect Chain 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 a supplied list of URLs as a redirect chain, detecting loops, protocol downgrades, and hop-count budget violations — returning a deterministic pass/advisory verdict.

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/redirect-chain-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/redirect-chain-check-e3f9099a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_It8GhNV0tRL5JHj5ghLCR

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 redirect-chain-check-e3f9099a -d '<json body>'
```

Example prompt: Check this redirect chain for loops, protocol downgrades, and hop budget with a max of 10 hops: ['https://example.com', 'http://example.com/page', 'https://example.com/final'] — tell me if it passes or has any issues.

## When to prefer this

Choose this endpoint when you need a deterministic, stateless, in-memory validation of a redirect chain without making any live HTTP requests — ideal for pre-flight checks before accepting, caching, or retrying a web response. Prefer it over live redirect-following tools when you already have the chain and need a structured, versioned, auditable verdict with explicit pass/advisory status.

## Known failure modes

- Malformed or non-URL strings in the urls array may produce parsing errors
- Exceeding maxItems of 256 URLs returns a validation error
- max_hops not supplied may default to an internal limit or return an error
- Payment failure via x402 protocol blocks the call
- Very large URL strings (near 8192 char limit) may be truncated or rejected

## How this service works

Redirect Chain Check: Redirect Chain Check checks a caller-supplied redirect chain for loops, downgrade, and hop budget from bounded caller-supplied values without an external provider. Call Redirect Chain Check 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 Redirect Chain Check as versioned deterministic JSON. Price: $0.001 USDC via x402 on Base. First-party,…

## Output

Returns versioned deterministic JSON containing normalized web evidence from the chain, individual findings for loop detection, protocol downgrade, and hop budget compliance, plus an explicit overall pass or advisory status verdict.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "urls": {
   "type": "array",
   "items": {
    "type": "string",
    "maxLength": 8192
   },
   "maxItems": 256,
   "description": "Urls supplied to Redirect Chain Check; used only for this bounded calculation and processed in memory without retention."
  },
  "max_hops": {
   "type": "integer",
   "description": "Max Hops supplied to Redirect Chain Check; used only for this bounded calculation and processed in memory without retention."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "hops": 1,
   "loop": false,
   "urls": [
    "https://example.com/",
    "https://www.example.com/home"
   ],
   "within_budget": true,
   "https_downgrade": false
  },
  "schema": "delx/util-redirect-chain-check/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "3453eef3c3df8628e97f753e043dfdda28418550e0e206ceea93554d8b86c83f",
   "external_calls": 0
  },
  "operation": "web_reliability:redirect_chain_check"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/redirect-chain-check-e3f9099a/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)