# Usenami Perp Basis

> Usenami Perp Basis is a paid API for AI agents from api.usenami.io, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14).

Returns per-venue perpetual futures basis (mark vs index price, basis_bps) and contango/backwardation structure for a given ticker

## Facts

- Endpoint: GET https://api.usenami.io/v1/perp/basis
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/usenami-perp-basis-77b5d472
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_EiFb2hqbYcPFf065omSW1

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 usenami-perp-basis-77b5d472
```

Example prompt: What's the current perp basis for BTC across all venues — give me the mark vs index price spread in basis points and tell me which venues are in contango vs backwardation.

## When to prefer this

Use this endpoint when you need to measure the spread between mark and index price on perpetual futures — specifically to compute basis in basis points, assess contango vs backwardation structure, or identify basis risk across venues. Prefer it over a general market snapshot when basis and price-source divergence are the primary signal, and over funding rate endpoints when you need price-level divergence rather than periodic payment rates.

## Known failure modes

- Ticker not supported — returns empty or error if the symbol is not tracked
- Venue publishes no index price — affected fields returned as null rather than an error
- Invalid input schema — missing required type or method fields causes a 400-level rejection
- Rate limiting or payment failure via x402 — call rejected if USDC payment is not processed

## How this service works

Per-venue basis for one crypto perpetual — mark versus index price, basis_bps = (mark−index)/index×10000, and contango/backwardation structure, across tracked CEX and DEX venues. Every venue has an index except Crypto.com, Variational and dYdX; dYdX publishes one oracle price, which is its mark. `venues_without_index` names the ones missing. Each venue also carries liquidity_state (live/dead/unknown), and a market with no trading is flagged unreliable however clean its basis looks.

## Output

Returns per-venue records for the requested ticker, each containing mark price, index price, basis_bps computed as (mark−index)/index×10000, and a contango or backwardation classification. Venues that do not publish an index price return null for those fields.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "method": {
     "type": "string"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/usenami-perp-basis-77b5d472/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.usenami.io](https://www.zero.xyz/host/api.usenami.io/llms.txt)