# NFT Rarity Score (Per-Token Trait Rarity)

> NFT Rarity Score (Per-Token Trait Rarity) is a paid API for AI agents from x402.professorsausages.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14).

Returns per-token trait rarity scores using alchemy_computeRarity and derives the rarest trait for a given NFT, with results cached up to 24 hours.

## Facts

- Endpoint: GET https://x402.professorsausages.com/nft/:chain/asset/:address/:tokenId/rarity
- 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/nft-rarity-score-per-token-trait-rarity-f0204372
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap__IURVeHIkRr9SbjciD5ZP

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 nft-rarity-score-per-token-trait-rarity-f0204372
```

Example prompt: How rare is token #4521 from the NFT contract 0xBC4CA0EdA7647A8aB7C2061c2E118A18a936f13d on Ethereum — which trait makes it the rarest?

## When to prefer this

Use this endpoint when you need per-token trait-level rarity scores for a specific NFT and want the rarest trait surfaced automatically. Prefer this over generic NFT metadata APIs when rarity ranking is the primary concern and you want Alchemy-backed computation without managing your own rarity calculations.

## Known failure modes

- Invalid or unsupported chain identifier returns an error
- Contract address not found or not an NFT contract returns empty or error
- Token ID does not exist within the contract returns 404 or empty response
- Alchemy upstream unavailable causes computation failure
- Cache miss on a newly minted token may cause slightly higher latency

## How this service works

Per-token trait rarity (alchemy_computeRarity) + derived rarest trait — cached ≤24h

## Output

Returns per-trait rarity scores for every attribute on the specified NFT token (computed via alchemy_computeRarity), plus a derived field identifying the single rarest trait. Results are served from cache if computed within the last 24 hours.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/nft-rarity-score-per-token-trait-rarity-f0204372/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.professorsausages.com](https://www.zero.xyz/host/x402.professorsausages.com/llms.txt)