To develop JSON-RPC bindings, clone the deltachat-core-rust repository:

git clone


To run online tests, set CHATMAIL_DOMAIN to a domain of the email server that can be used to create testing accounts:


Then run scripts/ to build debug version of deltachat-rpc-server and run deltachat-rpc-client tests in a separate virtual environment managed by tox.

Development Environment

Creating a new virtual environment to run the tests each time as scripts/ does is slow if you are changing the tests or the code and want to rerun the tests each time.

If you are developing the tests, it is better to create a persistent virtual environment. You can do this by running scripts/ This creates a virtual environment venv which you can then enter with:

. venv/bin/activate

Then you can run the tests with

pytest deltachat-rpc-client/tests/

Refer to pytest documentation <> for details.

If make the changes to Delta Chat core or Python bindings, you can rebuild the environment by rerunning scripts/ It is ok to rebuild the activated environment this way, you do not need to deactivate or reactivate the environment each time.

Using REPL

Once you have a development environment, you can quickly test things in REPL:

$ python
>>> from deltachat_rpc_client import *
>>> rpc = Rpc()
>>> rpc.start()
>>> dc = DeltaChat(rpc)
>>> system_info = dc.get_system_info()
>>> system_info["level"]
>>> rpc.close()