J++

Version 1.0.0 for macOS

Everything around your code. Nothing in the way.

J++ is a fast, native code editor for the Mac. Write in 95 languages, run and debug your code, query your data with SQL, push to GitHub and ask an AI assistant, all in one small app.

Coming soon See what it does

For macOS 12 or later · Apple silicon and Intel

The J++ window: a file explorer on the left, tabs, and a Python file with syntax colouring.
95languages with syntax colouring
< 10 MBthe whole download
0extensions to install
0data collected

Why J++

What makes it different.

Most editors start empty and ask you to assemble the rest. J++ starts complete, and it is made for the Mac and nothing else.

Truly native

Built with Cocoa for macOS, not a web page inside a wrapper. It starts fast, behaves like the rest of your Mac, and the whole app is a download of less than 10 MB.

Complete from the first launch

Run, debug, IntelliSense, SQL, GitHub and AI are part of the app. There is no marketplace to search and no extensions to choose, set up and keep updated.

Your data is one query away

Run SQL on Databricks, Snowflake, PostgreSQL, MySQL, SQL Server and SQLite. Even an Excel workbook or a CSV file becomes a table you can query.

AI on your terms

Connect your own Claude API key, any OpenAI-compatible service, or a model running on your Mac. J++ has no subscription, and your code is sent only when you ask.

Private by design

No account, no analytics, no advertising, no tracking. Passwords, tokens and API keys are kept in the macOS Keychain.

At home on your Mac

Liquid Glass on macOS 26, SF Symbols, SF Mono, and light and dark appearances that follow the system. One app for Apple silicon and Intel.

Features

One window. The whole job.

Edit

An editor that keeps up with you.

The editing engine is Scintilla, known for its speed with large files. Around it, J++ adds the tools you use all day.

  • Syntax colouring and code folding for 95 languages
  • Multiple cursors, column editing, macros and bookmarks
  • Find, replace and mark with regular expressions, across all open files
  • A file explorer that follows the folder as it changes
  • Session restore that keeps even your unsaved text
The J++ editor with the explorer sidebar and a Python file.

IntelliSense

It knows your code.

Completion as you type, parameter hints, descriptions when the pointer rests on a name, and marks under errors and warnings.

  • C, C++, Objective-C and Swift work at once, with the language servers that come with Xcode
  • Python works with no server at all: J++ reads your file and your installed modules
  • Go, Rust, TypeScript, Java, Ruby, Lua and more are used when their servers are on your Mac
A completion list showing the members of a Python object.

Run and debug

Press F5. In any language.

Compile and Run work for every language in the menu. The output appears under your code, and after an error the caret jumps to the line the compiler names.

  • A Python debugger with breakpoints, stepping, the variables of the frame and an expression field
  • Built-in checks for JSON, XML, YAML, TOML, HTML, CSS and more
  • Manage Compilers shows what is installed and downloads what is missing with Homebrew, npm or pip
The Python debugger paused on a line, with the variables listed beside the output.

Databases

SQL, right next to your code.

Save your connections once, then press ⌘↩ in a SQL tab. The results arrive in a grid you can copy or export as CSV.

  • Databricks and Snowflake through their own SQL APIs
  • PostgreSQL, MySQL, MariaDB, SQL Server and Azure SQL
  • SQLite files, with nothing to install
  • Excel workbooks and CSV files: every sheet becomes a table
A SQL query over an Excel workbook, with the results in a grid under the code.

AI assistant

An assistant that sees what you see.

Ask a question and the assistant reads the file in front of you and your selection. Insert and Replace Selection put the answer's code into the editor as one undo step.

  • Ready-made questions: Explain Code, Find Problems, Improve Code, Add Comments, Write Tests
  • Claude models with your own API key, with answers that appear as they are written
  • Any OpenAI-compatible endpoint, including a local model such as Ollama
The assistant panel beside the editor, explaining a bug in the selected function.

GitHub

From clone to push, without leaving.

Connect your account and J++ lists your repositories. The status bar shows the branch, what there is to push or pull, and how many files changed.

  • Clone, commit, push, pull and fetch
  • Publish a folder to a new repository
  • Create a gist from a file, or copy a link to the current line
The Clone Repository window with the list of the account's repositories.

What you will not find in J++.

No extensions

Everything on this page is in the app the first time you open it.

No account

You never sign in to J++. There is nothing to create.

No subscription

The AI assistant uses your own key or your own local model.

No telemetry

J++ does not measure you, and sends nothing to its author.

A guide for every feature, in English and Spanish.

Help ▸ J++ Guide describes each feature step by step, with screenshots in light and dark, and a table of every keyboard shortcut.

Give your code a better home.

J++ 1.0.0 is almost ready. The download will be available on this page.

Tell me when it is ready

For macOS 12 or later · Apple silicon and Intel

Compile, Run and Git use Apple's developer tools. Install Xcode, or its command line tools, to use them.