Beeceptor vs Kroki

Beeceptor lets you spin up a mock REST endpoint at a custom subdomain in seconds, define rule-based JSON, XML, plain-text, or binary responses through a no-code rule builder, and inspect the live requests hitting it in real time. It also doubles as an HTTP proxy for intercepting and rewriting responses from a real backend during development. The free tier needs no signup or API key — 50 requests/day per endpoint with up to 3 rules — with paid plans from $10/month unlocking private endpoints, higher volume, and CI/CD integration.

Kroki puts a single unified HTTP API in front of two dozen open-source diagram-as-code renderers, including PlantUML, Mermaid, GraphViz, D2, BPMN, Excalidraw, and WaveDrom, so callers send diagram source text and get back an image with no local toolchain to install. A GET request embeds the (deflate+base64-encoded) diagram directly in the URL, making it trivial to drop live diagrams straight into Markdown or HTML. The project and its public instance at kroki.io are free and open source, with self-hosting via Docker documented for anyone who needs a private instance.