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Delta Chat Logo

Rust CI

The core library for Delta Chat, written in Rust

Installing Rust and Cargo

To download and install the official compiler for the Rust programming language, and the Cargo package manager, run the command in your user environment:

$ curl -sSf | sh

On Windows, you may need to also install Perl to be able to compile deltachat-core.

Using the CLI client

Compile and run Delta Chat Core command line utility, using cargo:

$ RUST_LOG=deltachat_repl=info cargo run -p deltachat-repl -- ~/deltachat-db

where ~/deltachat-db is the database file. Delta Chat will create it if it does not exist.

Optionally, install deltachat-repl binary with

$ cargo install --path deltachat-repl/

and run as

$ deltachat-repl ~/deltachat-db

Configure your account (if not already configured):

Delta Chat Core is awaiting your commands.
> set addr
> set mail_pw yourpassword
> configure

Connect to your mail server (if already configured):

> connect

Create a contact:

> addcontact
Command executed successfully.

List contacts:

> listcontacts
Contact#10: <name unset> <>
Contact#1: Me √√ <>

Create a chat with your friend and send a message:

> createchat 10
Single#10 created successfully.
> chat 10
Single#10: []
> send hi
Message sent.

If uses DeltaChat, but does not receive message just sent, it is advisable to check Spam folder. It is known that at least treat such test messages as spam, unless told otherwise with web interface.

List messages when inside a chat:

> chat

For more commands type:

> help

Installing libdeltachat system wide

$ git clone
$ cd deltachat-core-rust
$ cmake -B build . -DCMAKE_INSTALL_PREFIX=/usr
$ cmake --build build
$ sudo cmake --install build


# run tests
$ cargo test --all
# build c-ffi
$ cargo build -p deltachat_ffi --release

Debugging environment variables

  • DCC_MIME_DEBUG: if set outgoing and incoming message will be printed

  • RUST_LOG=deltachat_repl=info,async_imap=trace,async_smtp=trace: enable IMAP and SMTP tracing in addition to info messages.

Expensive tests

Some tests are expensive and marked with #[ignore], to run these use the --ignored argument to the test binary (not to cargo itself):

$ cargo test -- --ignored


Install cargo-bolero with

$ cargo install cargo-bolero

Run fuzzing tests with

$ cd fuzz
$ cargo bolero test fuzz_mailparse --release=false -s NONE

Corpus is created at fuzz/fuzz_targets/corpus, you can add initial inputs there. For fuzz_mailparse target corpus can be populated with ../test-data/message/*.eml.

To run with AFL instead of libFuzzer:

$ cargo bolero test fuzz_format_flowed --release=false -e afl -s NONE


  • vendored: When using Openssl for TLS, this bundles a vendored version.
  • nightly: Enable nightly only performance and security related features.

Update Provider Data

To add the updates from the provider-db to the core, run:

./src/provider/ ../provider-db/_providers/ > src/provider/

Language bindings and frontend projects

Language bindings are available for:

The following "frontend" projects make use of the Rust-library or its language bindings:


  1. Out of date / unmaintained, if you like those languages feel free to start maintaining them. If you have questions we'll help you, please ask in the issues. ↩ ↩2