# B20Check Token Legitimacy Verifier

> B20Check Token Legitimacy Verifier is a paid API for AI agents from b20check.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).

Verifies whether a Base blockchain address is a legitimate factory-native B20 token, detecting copycats, impersonators, and reporting live issuer risk powers with a signed EIP-712 verdict.

## Facts

- Endpoint: GET https://b20check.com/v1/verify/:address
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/b20check-token-legitimacy-verifier-ac90028a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap___IU_cFo2Zf6K8yFSPgki

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 b20check-token-legitimacy-verifier-ac90028a
```

Example prompt: Before I buy this B20 token, can you run a legitimacy check on the contract address 0x1234...abcd on Base and tell me if it's a real factory-native B20, whether it has any dangerous issuer powers like mint or freeze, and give me the signed verdict?

## When to prefer this

Use this endpoint when you need to assess the legitimacy and risk profile of a specific B20 token on the Base blockchain before trading or integrating it, especially when you need a cryptographically verifiable (EIP-712 signed) verdict that can be independently validated. Prefer this over generic token scanners when you specifically need B20 factory-native verification, homoglyph-aware impersonation detection, or live issuer power reporting on Base.

## Known failure modes

- Invalid or malformed contract address returns an error response
- Address not found on Base network returns not-found error
- Non-B20 contract address may return a danger verdict or unsupported error
- Network congestion on Base may cause delayed or timeout responses
- Rate limiting if too many requests are made without payment

## How this service works

Legitimacy check for B20 tokens on Base. Verifies whether an address is a factory-native B20, detects copycats and known-asset imposters (homoglyph-aware), reports live issuer powers (mint, burn, pause, freeze, seize, admin) and issuer activity, and returns a danger/caution/ok verdict as an EIP-712-signed attestation an agent can independently verify.

## Output

Returns a signed EIP-712 attestation containing a three-tier verdict (danger/caution/ok), whether the address is a factory-native B20, copycat and homoglyph impersonation detection results, a live report of issuer powers (mint, burn, pause, freeze, seize, admin), and recent issuer activity. The signature can be independently verified on-chain.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/b20check-token-legitimacy-verifier-ac90028a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from b20check.com](https://www.zero.xyz/host/b20check.com/llms.txt)