Best AI IDEs in Japan

The Windsurf Editor is a free AI-powered IDE and AI coding assistant that accelerates development by providing intelligent code generation and agents in over 70 programming languages and more than 40 IDEs, including VSCode, JetBrains, and Jupyter Notebooks. With Windsurf, developers can write code faster, eliminate repetitive tasks, and stay in the flow state—whether they're working with Python, JavaScript, C++, or any other language. Built on billions of lines of open-source code, Windsurf Editor understands and anticipates your coding needs, offering multiline suggestions, automated unit tests, and even natural language explanations for complex functions. It’s perfect for streamlining code writing, reducing boilerplate, and cutting down the time spent on documentation searches. Trusted by individual developers and Fortune 500 companies alike, Windsurf Editor is your go-to solution for boosting productivity and writing better code. Try Windsurf for free today!

IntelliJ IDEA is a professional-grade integrated development environment (IDE) primarily designed for Java and Kotlin development. It helps developers write code faster by automating routine tasks and providing smart coding assistance. The IDE supports the full software development lifecycle, from design and coding to testing and deployment. IntelliJ IDEA stays up to date with the latest language features, such as full support for Java 24 and Kotlin K2 mode. It offers a smooth and enjoyable workflow that helps developers stay focused and productive. The platform also emphasizes data privacy and security, complying with industry standards like SOC 2.

Dropstone is an AI-assisted integrated development environment (IDE) designed to enhance software development efficiency. It adapts to a developer’s coding patterns, providing context-aware code suggestions, automated refactoring, and real-time error detection. The platform supports multiple programming languages and frameworks and integrates with version control systems. Dropstone also includes autonomous agents capable of analyzing project context, suggesting improvements, and automating routine tasks. By combining AI-driven code assistance with project management features, Dropstone helps developers and teams streamline workflows, reduce repetitive work, and deliver production-ready software more efficiently.

Take advantage of the language specific-aware syntax & error highlighting, code formatting, code completion, and quick documentation. Use smart search to jump to any class, file or symbol, or even any IDE action or tool window. It only takes one click to switch to the declaration, super method, test, usages, implementation, and more. Enjoy super fast navigation in your Rails project with an MVC-based project view and model, class, and gem dependencies diagrams. Follow community best practices with code inspections verifying your code for many types of possible errors and providing on-the-fly improvements with quick-fix options. Automated yet safe refactorings help clean up your code and keep it more maintainable. Rails-aware refactorings help you perform project-wide changes: for example renaming a controller will also rename the helper, views, and tests.

On-the-fly error detection and suggestions for fixes, quick and safe refactorings with one-step undo, intelligent code completion, dead code detection, and documentation hints help all Go developers, from newbies to experienced professionals, to create fast, efficient, and reliable code. Exploring and understanding team, legacy, or foreign projects takes a lot of time and effort. GoLand code navigation helps you get around with instant switching to shadowed methods, implementations, usages, declarations, or interfaces implemented by types. Jump between types, files or any other symbols, or find their usages and examine them with convenient grouping by usage type. Powerful built-in tools help to run and debug your applications. You can write and debug tests without any additional plugins or configuration effort, and test your applications right in the IDE. A built-in Code Coverage tool will make sure that your tests don’t miss anything important.

WebStorm is a powerful JavaScript and TypeScript integrated development environment (IDE) designed to boost developer productivity and enjoyment. It comes ready to use out of the box with essential tools for JavaScript, TypeScript, HTML, CSS, and popular frameworks like React, Angular, and Vue. WebStorm offers deep code understanding, fast navigation, safe refactoring, and built-in Git support. It automates complex tasks such as resolving merge conflicts and debugging tests, saving developers time. The IDE integrates advanced AI-powered coding assistance, including unlimited code completion and offline support. WebStorm’s customizable interface and plugin ecosystem make it adaptable to any developer’s workflow.

Fine is an AI-powered development platform designed to assist startups by automating tasks throughout the software development lifecycle. It offers a range of AI agent workflows for coding, debugging, testing, and code review, allowing teams to ship daily improvements and resolve pull requests faster. Fine can autonomously create and implement code, conduct pull request reviews, generate tests, and handle common issues without constant human input. The platform integrates seamlessly with GitHub and supports asynchronous work, making it particularly suitable for fast-paced startups. With real-time feedback and live previews, Fine improves productivity and streamlines the development process.

Benefit from context-aware code completion and generation, on-the-fly analysis and quick fixes, smart refactorings, live templates, and more. Install rustup from the IDE, and apply compiler-suggested fixes in a single click. You can even forget about manually attaching newly created Rust files to main.rs or adding popular crates to the list of dependencies. Have every syntax element highlighted, including inferred types and macros, cfg blocks, and unsafe code usages. Unlock comprehensive type information and quick access to language and crate documentation, and navigate your codebase with RustRover’s powerful search functionality. Run individual tests, test modules, or all the tests inside a project and select various Run targets. You can also create custom Run configurations with full support for developing CLI applications. Quickly troubleshoot failing tests by jumping to the relevant code from the error message in the console.

Aqua is the first IDE created specifically for test automation. It‘s an all-in-one workspace that supports Selenium, Cypress, and Playwright. Aqua is a polyglot IDE that understands Java, Python, JavaScript, TypeScript, Kotlin, and SQL. Get straight to testing without having to install and configure lots of plugins. Aqua boasts a unique feature set containing everything a test automation engineer needs on a daily basis. Aqua’s Web Inspector works like a built-in browser and allows you to capture any page element without switching to another tool. There is also the HTTP client for API testing and integration with databases, Docker, and version control. Aqua minimizes the hassle for even the most challenging tasks. The combination of intelligent code analysis, powerful search and refactoring capabilities, and overall ease of use enables you to boost your quality engineering productivity.

Kiro is an AI‑powered integrated development environment that brings structure to AI‑driven coding by converting natural‑language prompts into clear requirements, system designs, and discrete implementation tasks validated by robust tests. Built from the ground up for agentic workflows, it features spec‑driven development, multimodal chat, “agent hooks” that trigger background tasks on events like file saves, and an autopilot mode that autonomously runs large scripts while keeping you in control. With smart context management, Kiro reduces repetitive prompts and helps implement complex features across large codebases. Native MCP integrations let you connect to documentation, databases, and APIs, and you can guide development with images of UI designs or architecture diagrams. Enterprise‑grade security and privacy ensure safe deployment, while support for Claude Sonnet models, Open VSX plugins, and existing VS Code settings delivers a familiar yet AI‑supercharged experience.

Qoder is an agentic coding platform engineered for real software development, designed to go far beyond typical code completion by combining enhanced context engineering with intelligent AI agents that deeply understand your project. It allows developers to delegate complex, asynchronous tasks using its Quest Mode, where agents work autonomously and return finished results, and to extend capabilities through Model Context Protocol (MCP) integrations with external tools and services. Qoder’s Memory system preserves coding style, project-specific guidance, and reusable context to ensure consistent, project-aware outputs over time. Developers can also interact via chat for guidance or code suggestions, maintain a Repo Wiki for knowledge consolidation, and control behavior through Rules to keep AI-generated work safe and guided. This blend of context-aware automation, agent delegation, and customizable AI behavior empowers teams to think deeper, code smarter, and build better.

Eclipse Theia is an extensible platform to develop multi-language Cloud & Desktop IDEs with state-of-the-art web technologies. Not sure whether you need a web or desktop version or both? With Theia you can develop one IDE and run it in browsers or native desktop application from a single source. The Theia project is hosted at the Eclipse Foundation, a not-for-profit corporation, and is developed by a diverse community. Unlike other "open-source" projects, projects hosted at an Open-Source Foundation are protected against single-vendor decisions against the interest of the diverse community. Theia is designed in a modular way to allow extenders and adopters customizing and extending every aspect of it. Composing a custom IDE-like product is as easy as listing all needed extensions in a package.json file. Adding new functionality by implementing your own extensions is easy, too and provides all the flexibility you need.

Who wouldn’t like to code at the speed of thought while the IDE does all the mundane development tasks for them? But is that really possible for a tricky language like C++, what with its modern standards and heavily templated libraries? Why, yes, yes it is! See it to believe it. Generate tons of boilerplate code instantly. Override and implement functions with simple shortcuts. Generate constructors and destructors, getters and setters, and equality, relational, and stream output operators. Wrap a block of code with a statement, or generate a declaration from a usage. Create custom live templates to reuse typical code blocks across your code base to save time and maintain a consistent style. Rename symbols; inline a function, variable, or macro; move members through the hierarchy; change function signatures; and extract functions, variables, parameters, or a typedef.

Agentforce Vibes introduces vibe coding, a generative AI–powered approach that lets developers convert natural language instructions into production-ready Salesforce applications with enterprise-grade security, governance, and infrastructure. Unlike simpler vibe coding tools aimed at prototyping, Agentforce Vibes supports the full development lifecycle, ideation, building, testing, deployment, and observability, while integrating with Salesforce’s platform and trust layers. It functions as an AI-powered IDE (usable within VS Code or any VS Code-compatible environment) that understands your Salesforce schema and metadata, enabling features such as agentic code generation (Apex, HTML, CSS, JavaScript), intelligent rule enforcement, test case generation, debugging, rollbacks, and natural language DevOps. It supports multiple language models, is extensible via Model Context Protocol (MCP) with over 20 built-in tools, and allows reuse of existing code.