Scala HTTP Client Libraries
HTTP client libraries for Scala leverage functional programming paradigms. Akka HTTP is actor model-based, Http4s provides a pure functional approach, and ScalaJ-HTTP offers simple implementation. They enable flexible abstraction through type classes and monad transformers.
GitHub Star Comparison
| No | Name | GitHub Stars | Description | Trend | License | Type | Official Site |
|---|---|---|---|---|---|---|---|
| 1 | sttp | - | Unified HTTP client library for Scala. Provides common interface supporting multiple backends (Java HttpClient, Akka HTTP, http4s, OkHttp, etc.). Seamless integration with JSON processing (circe, uPickle, etc.), streaming (fs2, ZIO Streams, etc.), and functional programming libraries. | Established solid position as top choice for Scala HTTP client in 2025. Overwhelming support as 'HTTP client you always wanted in Scala' through unified interface and rich backend support. Continues as first choice in modern Scala development. | Apache 2.0 | Multi-backend | Official |
| 2 | http4s | - | Minimal and idiomatic HTTP service library for Scala. Pure functional approach based on cats-effect and FS2 streaming library. Emphasizes composability, achieving robust HTTP communication through I/O management. Scala.js and Scala Native compatible. | Maintains important position in Scala functional programming ecosystem in 2025. Particularly achieves advanced type safety and composability in combination with cats-effect, FS2, and ZIO. Continuously adopted in projects emphasizing pure functional approach. | Apache 2.0 | Functional/Streaming | Official |
| 3 | Akka HTTP | - | HTTP server and client library for Scala/Java. High-performance async HTTP communication based on Akka actor model, streaming support, intuitive API design with DSL. Mature solution optimized for microservices, high-load systems, and real-time communication. | Maintains stable important position in Scala/Akka ecosystem in 2025. Continues use especially in enterprise environments, high-load systems, and legacy system integration. Tendency to prioritize more lightweight solutions in new projects, but supported for proven track record and reliability. | Business Source License 1.1 | Actor-based | Official |
| 4 | scalaj-http | - | Simple Scala wrapper for Java HttpURLConnection. Lightweight with minimal dependencies, OAuth authentication support included. Simple API design specialized for basic HTTP operations, achieving quick HTTP communication without complex configuration. HTTP client with low learning cost. | Continues use for simple HTTP operations and learning purposes in 2025. Holds value for small-scale projects emphasizing lightweight and ease of use, and entry-level purposes for Scala beginners. Modern Scala development prioritizes sttp and http4s, but remains as choice addressing specific needs. | Apache 2.0 | Simple wrapper | Official |