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Okio is a Kotlin Multiplatform project. We’re still completing our feature coverage.

Compression (Deflater, Inflater, Gzip)


Concurrency (Pipe, Timeouts, Throttler)


Timeout is on all platforms, but only the JVM has a useful implementation.

Core (Buffer, ByteString, Source, Sink)

Available on all platforms.

File System

Available on all platforms. For JavaScript this requires Node.js.


Okio includes Kotlin implementations of MD5, SHA-1, SHA-256, and SHA-512. This includes both hash functions and HMAC functions.

Okio uses the built-in implementations of these functions on the JVM.