pd4web: Running PureData Patches in Browsers with Web Audio

Pd4Web v3.0.1

Type: Major internal rewrite (breaking changes)

This release is a complete rewrite of Pd4Web, migrating the core from Python to C++, introducing a new execution and messaging model, and significantly changing the public APIs. It also updates the Pure Data runtime and expands language support.

Core architecture

• Full rewrite from Python to C++.
• New native core focused on performance, determinism, and tighter integration with WebAssembly.
• Removal of the previous Python-based runtime and tooling.
• Significant internal refactoring; previous internals are not compatible.

Pure Data

• Updated bundled Pure Data version to Pd 0.56.
• Improved compatibility with modern Pd patches and externals.
• Better alignment with upstream Pd behavior.

Language and scripting support

• Added support for pdlua.
• Lua scripts can now be embedded and executed alongside Pd patches.
• Pd4Web also supports GUI objects, rendered with GPU;
• Improved extensibility for script-driven patches and control logic.

JavaScript and TypeScript API

• Completely redesigned JavaScript API.
• Previous JS/Python-facing APIs are no longer compatible.
• New, unified messaging system.
• Added TypeScript type definitions, by @richdouglasevans;
• Typed messaging APIs (sendMessage, file transfer, control helpers).
• API signatures now accurately reflect runtime behavior.

Build and toolchain

• Updated EMSDK version.
• Major improvements to CMake and build configuration.
• Fixed Pd4Web installation layout.
• More reliable cache handling and clean builds.
• Improved version reporting and consistency.

Documentation

• Updated documentation to reflect:

  • New C++ core.
  • New JavaScript / TypeScript APIs.
  • pdlua integration.

Breaking changes

• Python-based workflow removed.
• All previous APIs are obsolete.
• Existing projects must migrate to the new JavaScript / TypeScript API or keep using the version v2.3.0.
• Custom tooling built on top of the old runtime will not work without adaptation.

Compatibility

• Not compatible with Pd4Web ≤ 2.x.
• Requires project updates to use the new API and build system.

Notes

This release is recommended if you:

• Want Pd 0.56 support.
• Need pdlua integration with GPU rendering support;
• Prefer a native C++ core for performance and long-term stability (just for me I think);
• Are starting new Pd4Web projects or planning a migration.
• Want a more complete JavaScript API;