Hoverfly vs Servirtium

Hoverfly Cloud is a hosted API simulation and mocking platform for testing without live API dependencies. It handles HTTP/S services including REST, SOAP, XML, JSON, and GraphQL. Users can capture and replay traffic, generate simulations from OpenAPI specifications, and match requests by methods, headers, parameters, and bodies. Simulations can delay responses, inject faults or errors, and modify replies. A command-line interface supports scripted configuration and testing pipelines. Hoverfly and hoverctl binaries run on macOS, Linux, and Windows, while documentation covers Docker and Kubernetes installation. The underlying Hoverfly framework is open source under Apache 2, has no GUI, and is generally run locally or in a user’s infrastructure. Cloud use cases include performance testing, functional testing, and development.

Servirtium is an open-source testing library and command-line tool for recording HTTP interactions and replaying them offline. Saved interactions, called tapes, use readable Markdown that can include requests, responses, headers and bodies, making them shareable across languages and reviewable in Git diffs. A native record-and-replay engine has bindings for Go, Python, Java, .NET, Rust, Ruby, JavaScript and TypeScript, Dart, PHP, Haskell, Elixir, Pharo, Nim, Zig, Lua, Erlang and Gleam. It works with any unit-test or specification framework. The standalone CLI can serve tapes as HTTP stubs, lint them, and import or export HTTP Archive files, including captures from Chrome DevTools, Fiddler, Charles, mitmproxy and Postman. Redaction and tape normalization address transient values such as IDs and timestamps. Playback requires matching request headers and bodies unless masking is applied. Servirtium targets test automation, not production service replacement, and is available for API, Linux, macOS and self-hosted use.