Perry vs Static Hermes
Perry and Static Hermes both explore ahead-of-time JavaScript/TypeScript compilation, but they have different runtimes, toolchains, target goals, and maturity. Static Hermes remains an active branch of the Hermes project; Perry ships a pre-1.0 CLI and platform stack.
What is Static Hermes?
Hermes is Meta's JavaScript engine for React Native. The Static Hermes work lives on the static_h branch and includes an AOT-oriented runtime and compiler implementation; its own project discussion describes documentation and implementation as ongoing work.
What is Perry?
Perry parses TypeScript and JavaScript with SWC and compiles supported code ahead of time through LLVM. Native builds do not require an external Node.js installation or JavaScript engine, but they do statically link the Perry runtime and garbage collector. Perry is pre-1.0, implements a practical language and Node.js subset, and offers an optional embedded V8 fallback for code that needs engine semantics.
Side by side
| Feature | Perry | Static Hermes |
|---|---|---|
| Compiler path | SWC → Perry HIR → LLVM | Hermes Static H compiler/runtime branch |
| Runtime | Perry runtime + GC | Static Hermes runtime |
| Primary product scope | CLI, server, native UI, mobile, wearable, TV, Web/WASM | Hermes/React Native research and runtime ecosystem |
| Distribution | Pre-1.0 CLI with release packages | Source-oriented project workflow |
| Compatibility | Documented practical subset | Typed/static subset and Hermes semantics; check branch documentation |
Where Perry wins
- +Packaged Perry CLI and documented commands
- +Broader declared target and native UI scope
- +Published Perry limitations and benchmark artifact
Where Static Hermes wins
- +Backed by the established Hermes and React Native ecosystem
- +Deep integration potential with Hermes and React Native
- +Active compiler research from Meta and contributors
When to choose Perry
Choose Perry when its current CLI, target matrix, and UI stack match a product you can validate today.
When to choose Static Hermes
Evaluate Static Hermes when React Native/Hermes integration or compiler research is the primary goal and building from its current source workflow is acceptable.
Verdict
Neither project should be reduced to an unsupported 'production versus research' slogan. Evaluate the current branch, tooling, semantics, and target needed by your application.