OasDelta

Drop-in for oasdiff

Argument-compatible with oasdiff: alias oasdiff=oasdelta keeps your scripts, config files and CI checks working, with the same exit codes.

Byte-for-byte output

Every command and format is checked against the Go binary over the upstream test corpus, 10,461 golden comparisons on every commit, on Linux and Windows.

Faster than oasdiff

NativeAOT start-up, a tuned GC compiled into the binary and allocation-light parsing. CI benchmarks synthetic specs and real releases of the GitHub, Stripe and Kubernetes APIs, on Linux and Windows, against the official oasdiff release.

One self-contained file

About 10 MB with no runtime to install. Builds for Linux, Windows and macOS on x64 and Arm64.

Measured on every push

These numbers come from the latest run of the Benchmarks & site workflow: the NativeAOT build of oasdelta against the official oasdiff release binary, on GitHub-hosted runners. Full results and methodology →

Linux 4 cores, GitHub-hosted runner

Speed-up, real-world APIs

2.8×

geometric mean, GitHub, Stripe and Kubernetes releases

Speed-up, all cases

2.6×

range 1.1× – 5.9×

Cases where oasdelta is faster

23 / 23

median wall time, start-up included

Identical output

22 / 23

stdout and exit code, byte for byte

One case (k8s-core changelog -f json) prints the same entries as oasdiff in a different order. oasdiff’s own order there changes from run to run (5 orders in 5 runs); OasDelta’s does not. oasdiff sorts changes with a comparison that ignores some of their fields, and leaves changes that differ only in those fields in Go’s random map order.

Windows 4 cores, GitHub-hosted runner