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Systems programming with clarity, control, and portability.

PSI (Portable System Interface) is a compact language for building dependable software close to the machine. It brings direct hardware access and a familiar development model to multiple processor families.

Read the specification

A focused foundation for systems software

PSI is designed for engineers who need predictable performance and precise control over memory, hardware, and execution. Its compact surface keeps the essential parts of systems work visible without adding unnecessary ceremony.

A portable core provides consistent behavior across supported architectures, while clearly defined platform interfaces make specialized capabilities available when they matter. The result is software that is easier to reason about, review, and maintain.

Designed for portability and control

PSI stays close to the machine without being tied to one processor. Its toolchain handles the details that vary by target, so teams can focus on sound designs and reliable behavior instead of duplicated platform work.

Portable by design

Build for x86, x86-64, ARM, and AArch64 from one consistent foundation.

Direct and predictable

Work with memory, registers, system services, and synchronization primitives with confidence.

Ready to extend

Use a clearly scoped architecture interface when performance or hardware features demand it.

Small and understandable

A focused type system and minimal runtime keep behavior visible and maintenance straightforward.

Built for practical systems work

PSI is a strong fit for projects where efficiency, control, and portability are equally important. Explore the project repository for the full specification, implementation notes, and ongoing work.

The specification is implementation-independent, giving teams room to evolve the toolchain while preserving the language's observable behavior.