Definition
API Marketplace
A curated directory of APIs that AI agents can discover, evaluate, and pay for on a per-call basis.
An API marketplace is a catalog of services that agents can browse and consume. Traditional marketplaces like RapidAPI require human signup and API key management. Mithril's catalog is agent-native: every listed service supports x402 payments, so agents can discover a service, call it, and pay — all without pre-registration. The Mithril Catalog currently lists 21+ services across categories including search, crawl, data, email, image generation, LLM, and document parsing.
See also
Related terms
x402 Protocol
An open payment protocol that uses HTTP 402 Payment Required to enable pay-per-call API transactions for AI agents.
Pay-Per-Call
A pricing model where each individual API call is billed as a separate micro-transaction, rather than through subscriptions or rate-limited tiers.
AI Agent
An autonomous software system powered by a large language model that can take actions, use tools, and make decisions to accomplish goals.