The program can be built with debug support like this:

$ go run build.go -tags debug

Afterwards, extensive debug messages are written to the file in environment variable DEBUG_LOG, e.g.:

$ DEBUG_LOG=/tmp/restic-debug.log restic backup ~/work

If you suspect that there is a bug, you can have a look at the debug log. Please be aware that the debug log might contain sensitive information such as file and directory names.

The debug log will always contain all log messages restic generates. You can also instruct restic to print some or all debug messages to stderr. These can also be limited to e.g. a list of source files or a list of patterns for function names. The patterns are globbing patterns (see the documentation for path.Glob), multiple patterns are separated by commas. Patterns are case sensitive.

Printing all log messages to the console can be achieved by setting the file filter to *:

$ DEBUG_FILES=* restic check

If you want restic to just print all debug log messages from the files main.go and lock.go, set the environment variable DEBUG_FILES like this:

$ DEBUG_FILES=main.go,lock.go restic check

The following command line instructs restic to only print debug statements originating in functions that match the pattern *unlock* (case sensitive):

$ DEBUG_FUNCS=*unlock* restic check


Contributions are welcome! Please open an issue first (or add a comment to an existing issue) if you plan to work on any code or add a new feature. This way, duplicate work is prevented and we can discuss your ideas and design first.

More information and a description of the development environment can be found in A document describing the design of restic and the data structures stored on the back end is contained in Design.

If you’d like to start contributing to restic, but don’t know exactly what do to, have a look at this great article by Dave Cheney: Suggestions for contributing to an Open Source project A few issues have been tagged with the label help wanted, you can start looking at those:


Important: If you discover something that you believe to be a possible critical security problem, please do not open a GitHub issue but send an email directly to If possible, please encrypt your email using the following PGP key (0x91A6868BD3F7A907):

pub   4096R/91A6868BD3F7A907 2014-11-01
      Key fingerprint = CF8F 18F2 8445 7597 3F79  D4E1 91A6 868B D3F7 A907
      uid                          Alexander Neumann <>
      sub   4096R/D5FC2ACF4043FDF1 2014-11-01


Backward compatibility for backups is important so that our users are always able to restore saved data. Therefore restic follows Semantic Versioning to clearly define which versions are compatible. The repository and data structures contained therein are considered the “Public API” in the sense of Semantic Versioning. This goes for all released versions of restic, this may not be the case for the master branch.

We guarantee backward compatibility of all repositories within one major version; as long as we do not increment the major version, data can be read and restored. We strive to be fully backward compatible to all prior versions.

Building documentation

The restic documentation is built with Sphinx, therefore building it locally requires a recent Python version and requirements listed in doc/requirements.txt. This example will guide you through the process using virtualenv:

$ virtualenv venv # create virtual python environment
$ source venv/bin/activate # activate the virtual environment
$ cd doc
$ pip install -r requirements.txt # install dependencies
$ make html # build html documentation
$ # open _build/html/index.html with your favorite browser