- Has about 10 services in production at thousands of requests per second.
- Uses http4s extensively in its internal services and open source projects.
- a purely functional Scala client for CouchDB
- Eve Online fleet buddy based on the CREST API
- an open source demo app built with http4s
- a httpbin built with http4s (source)
- rho (ρ)
- a self-documenting HTTP server DSL built upon http4s
- A simple link-shortener