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5,399 sites implement API catalog

of 14,351 tested · measured 2026-08-23

every listed site fetched, 23 Aug 2026 · 14,351 listed

Checks passed across the 5,399 probed hosts: Markdown negotiation 3,473 · Markdown twin at a predictable URL 637 · llms.txt 3,824 · API catalog 5,399 · MCP server card answers 923.

What API catalog is

A machine-readable catalogue of a site's APIs at a well-known location, so an agent can find the interface without reading the documentation. Usually an OpenAPI document, discovered through /.well-known/api-catalog. Read RFC 9727 — it is the authority on the design and we are not trying to be.

How we test it

We fetch the well-known path and require a 200 with a parseable document.

A link to documentation is not a catalogue. We count the document an agent can parse, not the page a person can read.

Sites that implement it

5.9% of these are on teachify, 0.8% of these are on mintlify. The platform supplies the machinery; the domain signals the commitment, and a report says which applies.

✓VibeMarketolog agi.vibemarketolog.ru +2 more hosts on this domain
Russian AI marketing platform offering agents for advertising, analytics, and sales with 24/7 automation and strategy management.
✓Aigon aigon.ai
Aigon provides AI agents focused on productivity, education, property, and facilities management with an emphasis on privacy and security.
✓BibiGPT aitodo.co
BibiGPT is an AI tool that summarizes and transcribes audiovisual content from multiple platforms with timestamps and structured outputs.
✓Mewayz app.mewayz.com
Mewayz is an all-in-one business management platform offering over 144 modules including CRM, HRM, accounting, projects, and POS.
✓Ben Milne benmilne.com
Personal blog by Ben Milne featuring essays on value design, protocol thinking, and stablecoin topics.
✓BibiGPT bibigpt.co
BibiGPT is an AI tool that summarizes and transcribes audiovisual content from multiple platforms with timestamped structured outputs and API access.
✓Bl1nk bl1nk.co
Bl1nk offers NFC and QR digital business cards with AI assistant, lead capture, and CRM integration.
✓Business.Digital business.digital
Business.Digital is a digital agency offering consulting and implementation for websites, shops, ERP, AI, and software since 2006.
✓Commodity Monitor commodity.worldmonitor.app +2 more hosts on this domain
Real-time commodity markets dashboard tracking mining sites, processing plants, commodity ports, supply chains, and global trade flows with live context.
✓CostLoop costloop.app
CostLoop is a SaaS tool for freelancers, startups, and SMBs to track software subscriptions, renewal dates, costs, and detect savings opportunities.
✓TheBaby Agent Ecosystem craigmbrown.com
Provides AI agent security audits, a marketplace with ERC-8004 passports, and API services with tiered pricing.
✓Cyberkov cyberkov.com
Cyberkov is a cybersecurity and signal security company in Kuwait offering penetration testing, TSCM, MDR, SOC, digital forensics, and counter-espionage services.

The 10,512 listed sites that have a working MCP server or an API catalog, through the API — a wider set than the one this page counts: every one, in a fixed order, 25 per call, with the total stated.

Own a site?

API catalog is one signal among several. The rubric says exactly what we look for and how each tier is reached, and a probe can be requested — the probe decides, never the request.

Method and date

Measured 2026-08-23. every listed site fetched, 23 Aug 2026 · 14,351 listed Every figure on this page carries the population it was measured against; a count without a denominator is not a measurement. How the index is built · All standards.