Third-Party Notices
Last Updated: June 14, 2026
RtlStudio uses the open-source software described in this notice. We extend our sincere thanks to the many communities and organizations that develop, maintain, and share these projects.
RtlStudio ships open-source HDL tools and UI libraries as vendored WebAssembly or JavaScript under vendor/. The IDE shell (index.html, css/, js/) is RtlStudio application code and is not listed here.
Copyleft components (corresponding source)
These engines use copyleft licenses. Where the license requires it, RtlStudio publishes WASM build scripts or corresponding source.
| Component | Role | License | Source |
|---|---|---|---|
| Icarus Verilog | Verilog simulation | GNU GPL v2 or later | semisgdh/iverilog-wasm |
| Verilator | SystemVerilog simulation | GNU LGPL v3 | semisgdh/sgdh-verilator |
| Surfer | VCD waveform viewer | EUPL 1.2 | surfer-project/surfer |
The browser IDE shell remains separate from these vendored engines; RtlStudio does not distribute them as a single linked binary that would copyleft the entire application.
Permissive & attribution-only components
The following are bundled under permissive licenses (MIT, ISC, Apache 2.0, and similar). RtlStudio is not required to publish application source because of these components; upstream copyright notices are preserved in vendor/.
| Component | Role | License |
|---|---|---|
| Yosys | Logic synthesis | ISC |
| Slang | HDL lint / elaboration | MIT |
| Verible | Verilog formatting / lint | Apache 2.0 |
| Clang / WASI SDK | Browser C++ toolchain | Apache 2.0 |
| Monaco Editor | Code editor | MIT |
| SkyWater 130nm PDK | Synthesis technology mapping (Pro entitlement in RtlStudio; upstream Apache 2.0) | Apache 2.0 |
| WaveDrom | Timing diagrams | MIT |
| Z3 | Formal / constraint solving | MIT |
| Mermaid, markdown-it, DOMPurify, JSZip, elkjs, netlistsvg, … | Readme / diagram / UI support | MIT / ISC / Apache 2.0 (per upstream) |
Full upstream license texts are included with each package under vendor/.