Native footprint 🔗

Local Linux x86_64 measurements from 2026-10-25 for a small application with plain-text and JSON GET/POST routes.

Deployment	Packaged MiB	Stripped MiB	First HTTP ms	Idle RSS MiB	After requests RSS MiB
Undertow / GraalVM Native Image	41.56	41.56	30.5	34.7	41.3
Undertow / JVM	17.71	—	599.4	94.3	105.2
http4s / JVM	36.70	—	1413.8	183.2	201.8
http4s / Scala Native, release-fast	22.12	18.39	30.1	30.9	43.6
http4s / Scala Native, release-size	21.81	18.00	31.8	30.5	43.2

Startup and RSS are medians over five fresh processes on a warm host/filesystem. First HTTP is a successful GET /plaintext; idle RSS is sampled one second later. Post-request RSS is sampled one second after 300 sequential mixed plain-text/JSON GET/JSON POST requests. Successful requests, Unicode JSON, invalid input (400), and missing routes (404) were checked over real HTTP. The stripped Scala Native copies passed the same HTTP checks; GraalVM output is already stripped.

JVM sizes are fat JARs and exclude the JVM. Native executables require OS shared libraries. Stripped sizes use strip --strip-unneeded; startup/RSS figures refer to the original packaged executables. These are small example applications; the figures do not describe concurrent-load throughput, container size, or Lambda cold starts.

Environment: Intel Core i7-1165G7, Scala CLI 1.16.0, Scala 3.9.0, Sharaf 0.20.0, Temurin 21.0.10, GraalVM CE 25.0.2 (O2, Serial GC, compatibility CPU target), http4s/Ember 1.0.0-M48, Scala Native 0.5.12 with multithreading, Immix GC and no LTO. Local Clang 14 emitted a deprecation warning; Scala Native recommends Clang 16 or newer. The http4s examples explicitly set body headers for compatibility with published Sharaf 0.20.0.

snunit is excluded: its example compiled, but linking required the missing local libunit dependency. A snunit comparison must include the Unit daemon and application workers together.