Stoplight
Design-first platform for creating, governing, and documenting OpenAPI specifications. Bundles a visual editor, Spectral (JSON/YAML linter), Prism (mock server), and Elements (docs renderer) into one workflow. Teams use it to enforce API style guides across large API portfolios.
Speakeasy
Takes an OpenAPI spec and generates polished, type-safe client SDKs across multiple languages, Terraform providers, and MCP servers for AI agent integration. Handles pagination, retries, webhooks, and streaming out of the box. Increasingly positioning itself as the API platform for the agent era.