probe-web

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Browser support and limitations ​

Browsers ​

Chrome, Edge, Opera (desktop)FirefoxSafari
WebUSB transport✓✗✗
WebSocket transport✓✓✓
Serial monitor (WebSerial)✓✗✗
Watching files (File System Access)✓✗✗

Firefox and Safari do not implement WebUSB, WebSerial or the File System Access API. They can use everything else over the WebSocket transport. Chrome on Android has WebUSB but is not tested.

WebUSB needs a secure context: https://, or http://localhost and http://127.0.0.1 during development.

Known limitations ​

  • No disassembly over WebUSB. probe-rs disassembles with capstone, a C library, which the in-browser build does not include. The disassembly panel and the DAP adapter report it as unavailable. probe-rs serve provides it for Arm and RISC-V. It has no Xtensa disassembler.
  • Semihosting in the browser is console-only. Output to stdout and stderr and exit codes work. File operations are refused, because a page has no host filesystem.
  • No SWO or trace. probe-web has no SWO or ITM viewer.
  • One tab per probe. A second tab cannot open a probe another tab holds. It gets a probe-in-use-other-tab error. Native tools also cannot use the probe while a tab holds it.
  • CMSIS-DAP v1 (HID) probes do not work over WebUSB. Browsers do not let WebUSB claim HID interfaces. Use probe-rs serve.
  • ST-Link and WCH-Link are untested over WebUSB. See Supported hardware.
  • Chip auto-detection only works for chips whose debug ROM tables identify them, as with native probe-rs. Name the chip otherwise.
  • Xtensa stack traces continue past the entry trampoline into unnamed ROM frames. The named frames above them are correct.
  • probe-rs forks. The WebUSB transport and probe-rs serve build from forks of probe-rs until the async and wasm work is upstream. See Architecture.
  • Five of the six packages ship TypeScript source, not a compiled build, so a consuming bundler compiles them along with your code. @probe-web/ui is the exception: it ships compiled JavaScript, because its components use decorators and no npm package can tell a consumer's toolchain to enable them. The one setting still required is no dependency pre-bundling for @probe-web/client, whose Worker and wasm are addressed with new URL(..., import.meta.url). Getting started has it. In Node the source-shipping packages need tsx or another loader: Node's own type stripping refuses files under node_modules.