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Trezor Communication Daemon aka Trezor Bridge (written in Go)

Only compatible with Chrome (version 53 or later) and Firefox (version 55 or later).

status: spec Chrome Firefox Edge

Install and run from source

trezord-go requires go >= 1.12

GO111MODULE=auto go get
GO111MODULE=auto go build
./trezord-go -h


If you are new to Go and you are confused how come you should not clone the repository yourself, this is indeed the Go way. If you need to modify the code you can simply cd into the directory ($GOPATH/src/ and do whatever you please. Running go build inside that directory will produce a new executable at the same place. Running go build will produce a new executable in $GOPATH/bin. Both are built from your local copy in $GOPATH/src.

Debug mode

When built with -tags debug a debug mode is enabled. This disables CORS which is helpful for local development and when run inside a docker image.

Update from source

go clean
GO111MODULE=auto go get -u
GO111MODULE=auto go build -a

On Linux don't forget to install the udev rules if you are running from source and not using pre-built packages.

Guide to compiling packages


  • go get
  • docker pull karalabe/xgo-latest
  • make sure xgo and docker are in $PATH
  • cd release && make all; the installers are in installers

Quick guide to cross-compiling


  • go get
  • docker pull karalabe/xgo-latest

Compiling for officially supported platforms:

  • $GOPATH/bin/xgo -targets=windows/amd64,windows/386,darwin/amd64,linux/amd64,linux/386 .

Emulator support

Trezord supports emulators for both Trezor versions. However, you need to enable it manually; it is disabled by default. After enabling, services that work with emulator can work with all services that support trezord.

To enable emulator, run trezord with a parameter -e followed by port, for every emulator with an enabled port

./trezord-go -e 21324

If you want to run this automatically on linux, do

sudo systemctl edit --full trezord.service

and edit the service file (and maybe restart the trezord service). On mac, you will need to edit


and edit the last <string> in the plist. (And also probably restart the pc.)

You can disable all USB in order to run on some virtuaized environments, for example Travis

./trezord-go -e 21324 -u=false

API documentation

trezord-go starts a HTTP server on http://localhost:21325. AJAX calls are only enabled from subdomains.

Server supports following API calls:

parameters result type description
{version: string} Returns current version of bridge
Array<{path: string,
session: string | null}>
Lists devices.
path uniquely defines device between more connected devices. Two different devices (or device connected and disconnected) will return different paths.
If session is null, nobody else is using the device; if it's string, it identifies who is using it.
request body: previous, as JSON like enumerate Listen to changes and returns either on change or after 30 second timeout. Compares change from previous that is sent as a parameter. "Change" is both connecting/disconnecting and session change.
PATH: path of device
PREVIOUS: previous session (or string "null")
{session: string} Acquires the device at PATH. By "acquiring" the device, you are claiming the device for yourself.
Before acquiring, checks that the current session is PREVIOUS.
If two applications call acquire on a newly connected device at the same time, only one of them succeed.
SESSION: session to release {} Releases the device with the given session.
By "releasing" the device, you claim that you don't want to use the device anymore.
SESSION: session to call

request body: hexadecimal string
hexadecimal string Both input and output are hexadecimal, encoded in following way:
first 2 bytes (4 characters in the hexadecimal) is the message type
next 4 bytes (8 in hex) is length of the data
the rest is the actual encoded protobuf data.
Protobuf messages are defined in this protobuf file and the app, calling trezord, should encode/decode it itself.
SESSION: session to call

request body: hexadecimal string
0 Similar to call, just doesn't read response back. Also forces the message to be sent even if another call is in progress. Usable mainly for debug link and workflow cancelling on Trezor.
SESSION: session to call 0 Similar to call, just doesn't post, only reads. Usable mainly for debug link.

Debug link support

Trezord has support for debug link.

To support an emulator with debug link, run

./trezord-go -ed 21324:21325 -u=false

this will detect emulator debug link on port 21325, with regular device on 21324.

To support WebUSB devices with debug link, no option is needed, just run trezord-go.

In the enumerate and listen results, there are now two new fields: debug and debugSession. debug signals that device can receive debug link messages.

Session management is separate for debug link and normal interface, so you can have two applications - one controlling trezor and one "normal".

There are new calls:

  • /debug/acquire/PATH, which has the same path as normal acquire, and returns a SESSION
  • /debug/release/SESSION releases session
  • /debug/call/SESSION, /debug/post/SESSION, /debug/read/SESSION work as with normal interface

The session IDs for debug link start with the string "debug".