Python 3.14 Preview: REPL Autocompletion and Highlighting

Python 3.14 introduces improvements to its interactive shell (REPL), bringing a more modern, colorful, and user-friendly environment. The new features make the Python 3.14 REPL a powerful tool for experimentation. Whether you’re testing a quick idea, exploring a new library, or debugging a tricky snippet, the REPL gives you instant feedback—no files, no setup, just type and run.

The default CPython REPL intentionally kept things minimal. It was fast, reliable, and available everywhere, but it lacked the richer, more ergonomic features found in tools like IPython or ptpython. That began to change in Python 3.13, when CPython adopted a modern PyREPL-based shell by default, adding multiline editing, better history navigation, and smarter Tab completion.

By the end of this tutorial, you’ll understand that:

• In Python 3.14’s REPL, autocompletion is on by default. You just need to press Tab in the context of an import statement to see possible completion suggestions.
• The REPL highlights Python syntax in real time if your terminal supports ANSI colors.
• Python 3.14 allows you to customize the color theme with the _colorize.set_theme() experimental API and the PYTHONSTARTUP script.
• You can disable the syntax highlighting by setting NO_COLOR=1 or PYTHON_COLORS=0 in your environment.

Autocompleting module names during import statements makes interactive coding smoother and faster, especially for learning or exploratory tasks. In addition, the colored syntax in the REPL improves readability, making it easier to spot typos and syntax issues.

Take the Quiz: Test your knowledge with our interactive “Python 3.14 Preview: REPL Autocompletion and Highlighting” quiz. You’ll receive a score upon completion to help you track your learning progress:

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Interactive Quiz

Python 3.14 Preview: REPL Autocompletion and Highlighting

Take this quiz to explore Python 3.14's REPL upgrades! Test your knowledge of new autocompletion tools and built-in syntax highlighting.

The Interactive REPL Before Python 3.14

When you first install Python, one of the most immediate ways to try it out is through the interactive REPL (Read–Eval–Print Loop) in your command line or terminal. The REPL is a shell that lets you type Python code, run it instantly, and see the result. It’s a quick-start environment perfect for experimentation, learning, and debugging without the overhead of creating and running separate scripts.

For years, the default CPython REPL kept things lightweight and fairly minimal, with very few features. In contrast, tools like IPython, bpython, and ptpython have offered richer interactive experiences.

This landscape has been changing lately. Starting in Python 3.13, the default REPL is based on PyPy’s pyrepl, which is written in Python and designed for extensibility and safety. It’s also a more capable interactive shell with a modern set of features:

• Color by default: Take advantage of colorized prompts and tracebacks. You can also control this behavior with the PYTHON_COLORS or NO_COLOR environment variables.
• Quick REPL commands: Use exit, quit, help, and clear as commands rather than function calls with parentheses.
• Built‑in help browser: Press F1 to open a help viewer in your pager so you can browse docs for Python, modules, and objects.
• Persistent history browser: Press F2 to open your command history in a pager and keep it across sessions so you can copy and reuse code.
• Multiline editing: Edit and rerun entire code blocks—functions, classes, loops—as a single unit. The block structure is preserved in your history.
• Robust pasting and paste mode: Paste whole scripts or larger code blocks reliably by default. Optionally, you can access paste mode with F3, although direct pasting usually works without issue.
• Smarter Tab completion: Completions update as you type and hide irrelevant suggestions to reduce noise.

In Python 3.14, the REPL has taken another leap forward by including the following improvements:

• Extended autocompletion that now covers module and submodule names in import statements
• Live syntax highlighting that makes your interactive code as readable as in your favorite code editor or IDE

You don’t need to perform any extra installation or configuration to start using these new features as long as your terminal supports ANSI color output.

In the sections ahead, you’ll explore what these improvements look like in practice, learn how to use them in your workflow, and pick up some troubleshooting tips for when things don’t behave quite as expected.

Autocompletion Improvements

Python 3.14 extends the autocompletion logic to recognize import contexts and suggest module or package names accordingly. Now, when you type an import or from ... import statement and press Tab, the REPL will search the import path for available module names matching the partial text.

For example, if you type import and then press Tab twice, you’ll get the complete list of currently available modules and packages. If you start typing a module’s name like pat and press Tab, the REPL will automatically complete the pathlib name because it matches uniquely with the partial text.