# Accept Encoding Rank

> Accept Encoding Rank is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Ranks supported content codings against HTTP Accept-Encoding header weights and returns a normalized pass/advisory result as deterministic versioned JSON.

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/accept-encoding-rank
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/accept-encoding-rank-b53b11ee
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Sevw92qprfjzSL4IgRELu

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 accept-encoding-rank-b53b11ee -d '<json body>'
```

Example prompt: Rank these offered encodings — gzip, br, deflate, identity — against the Accept-Encoding header 'br;q=1.0, gzip;q=0.8, *;q=0.1' and tell me which one to use and whether it passes.

## When to prefer this

Choose this endpoint when you need a deterministic, stateless, server-side computation of HTTP content encoding negotiation — especially before accepting, caching, redirecting, or retrying a web response. Prefer it over rolling your own Accept-Encoding parser when you need a normalized, versioned result with explicit pass/advisory output suitable for agent pipelines.

## Known failure modes

- Malformed Accept-Encoding header value causes parsing failure or unexpected ranking output
- Offered codings list exceeds 256 items, triggering rejection
- Header string exceeds 8192 character limit
- Empty offers array returns no ranking with advisory status
- Unrecognized coding tokens may be ranked at lowest priority or flagged as unknown

## How this service works

Accept Encoding Rank: Accept Encoding Rank ranks supported content codings against Accept-Encoding weights from bounded caller-supplied values without an external provider. Call Accept Encoding Rank 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 Accept Encoding Rank as versioned deterministic JSON. Price: $0.001 USDC via x402 on Base. First-party, stateless, me…

## Output

Returns versioned deterministic JSON containing normalized web evidence (the parsed Accept-Encoding weights and offered codings), a computed ranking of the offered codings by preference weight, and an explicit pass or advisory status indicating whether the negotiation is valid.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "header": {
   "type": "string",
   "maxLength": 8192,
   "description": "Header supplied to Accept Encoding Rank; used only for this bounded calculation and processed in memory without retention."
  },
  "offers": {
   "type": "array",
   "items": {
    "type": "string",
    "maxLength": 8192
   },
   "maxItems": 256,
   "description": "Offers supplied to Accept Encoding Rank; used only for this bounded calculation and processed in memory without retention."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "ranked": [
    {
     "offer": "br",
     "quality": 1
    },
    {
     "offer": "gzip",
     "quality": 0.8
    }
   ],
   "selected": "br"
  },
  "schema": "delx/util-accept-encoding-rank/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "38b764e7204eb17f82ed20cce029e6a2c8cd6149a609fe91d9a2ab05143350ab",
   "external_calls": 0
  },
  "operation": "web_reliability:accept_encoding_rank"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/accept-encoding-rank-b53b11ee/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)