vet402 vs ISBNLab

A side-by-side comparison built from both listings. Blank cells mean the company has not given that detail; we never guess.

vet402 compared with ISBNLab
Detail	vet402	ISBNLab
What it does	Independent measurement of x402 payments for AI agents	Book metadata database and API for searching, converting and using ISBN data
Stage	Startup	Not given
Founded	Not given	Not given
Based in	JP	US
Pricing model	Not given	Freemium
Pricing	Free: US$0 per month (1,000 lookups a month); Pro: US$49 per month (50,000 lookups a month); Scale: US$199 per month (500,000 lookups a month)	Free: $0/mo with 1,000 Daily Calls; Standard: $5/mo with 5,000 Daily Calls; Pro: $15/mo with 15,000 Daily Calls. Custom plans available.
Key features	API key management with free tier at 10 requests per minute Multi-language SDK support including curl, TypeScript, Python, MCP and no-code n8n L0, L1 and L2 measurement layers for payment verification On-chain settlement re-verification across multiple blockchains Trust score and decision API (ALLOW, WARN, BLOCK) Public impact ledger recording all purchases and deliveries Support for Base, Arc, Celo, Arbitrum One, Avalanche C-Chain, BNB Chain, Solana, Stellar, Tempo and XRPL	REST and GraphQL API ISBN validation and conversion Multiple response formats: JSON-LD, JSON and CSV OpenAPI and Swagger documentation Official client libraries for PHP, Python, TypeScript/JavaScript and Go Catalog of 102.1M book editions Groups every edition of a book together Comprehensive book data: ISBN-10, ISBN-13, EAN, ASIN, title, authors, publishers Author information including names, birth and death dates, biography and photos
What makes it different	Only service that buys from x402 endpoints with its own funds and publishes settle-through receipts Published methodology and measured error rates for transparency Non-custodial design that never holds customer funds or keys Free API tier for reads without key requirement	One consistent schema for every book keyed by ISBN Catalog of 102.1M book editions ISBN validation and conversion for any valid ISBN, not just books in the catalog Suitable for beginner, intermediate and advanced users
Community votes	0	0
DR (Domain Rating by Ahrefs)	26 −1 (down) since last check	4 no change since last check
Trust Flow (Majestic)	2	1
Citation Flow (Majestic)	23	32
Referring domains (Majestic)	18	6

5 details filled in for both companies.

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