Codestral is Mistral AI's model for writing and completing code, first released in May 2024 and trained on more than 80 programming languages.
In plain words
Codestral is built for coding jobs such as finishing a function, writing tests or filling in a gap in existing code. Filling a gap uses 'fill-in-the-middle': the model sees the code before and after the cursor and writes what goes between. The first version had 22 billion parameters and open weights under a non-production licence for research and testing. An updated Codestral, released at the end of July 2025, is listed in Mistral's Premier tier rather than under an open licence.
A quick example
Imagine your cursor sits inside an empty function between its name and a line that uses its result. Codestral would read both sides and suggest a body that fits, like a smart autocomplete.
Where you'll meet it
- Fill-in-the-middle completion inside code editors.
- Writing tests and small functions.
Related
Sources
- DocsCodestral, Mistral AI · read 29 Sept 2026
- DocsModels overview, Mistral AI docs · read 29 Sept 2026
Checked by WhatIsAI against the sources above · 29 Sept 2026. Spotted an error? Report it.