Jonas Helming, Maximilian Koegel and Philip Langer co-lead EclipseSource, specializing in consulting and engineering innovative, customized tools and IDEs, with a strong …
How to Build a Custom IDE or Tool
Building tools or Integrated Development Environments (IDEs) is a complex process, and without a clear strategy, it’s easy to get lost in technical details too soon. At EclipseSource, our blog articles often focus on specific technical aspects of tool building. However, when working with our customers on strategic tool and IDE projects, our involvement typically begins long before the first line of code is written. In these early phases, it is crucial to step back and consider high-level aspects that will shape the entire project. While these considerations are often driven by the specific requirements and context of a specific tool product, there are common patterns and best practices that likely apply to almost all custom tools and IDEs.
In this article, we outline the most important high-level considerations for building tools and IDEs. The order presented here reflects a perceived order of importance, offering a roughly chronological guide on what to consider first. That said, many of these aspects need to be addressed in parallel, and most will require revisiting throughout the project. This isn’t an exhaustive technical guide but rather a checklist to help you stay focused on the bigger picture. Some points may seem obvious, but in our experience, continuously revisiting even basic principles can provide significant value, as it’s easy to lose sight of them in the complexity of modern toolchains.
We hope you find this guide helpful!
1. Define the Purpose, Target Audience and MVP
3. Decide on the Platform: Cloud, Web, Desktop, All of them?
5. Choosing the Right Foundation for Your Tool
6. Select and Adopt Additional Technologies
7. Build Proof of Concepts (PoCs)
1. Define the Purpose, Target Audience and MVP
This step might seem obvious, yet it is surprisingly often overlooked—particularly when tools and IDEs are developed without formal product management oversight. While this informal approach can sometimes accelerate the perceived progress in the beginning, it leads to a vague shared vision of the tool’s purpose and audience.
Why is this important? Clearly defining the purpose and target audience allows you to focus your development on what matters, and consequently maximize value while minimizing effort and cost. Tools and IDEs often serve highly specific needs. For example:
Internal tools for development experts may prioritize expert features over a polished UI.
External-facing tools, such as customer-facing IDEs, require excellent user experiences since they often serve as an introduction to an ecosystem.
Understanding the core purpose and audience influences all subsequent design and implementation decisions. What problem is your tool solving? Who are the users—developers, engineers, or non-technical professionals? Addressing these questions from the outset provides a significant advantage.
Once the purpose and target audience are defined, the next step is to establish a Minimal Viable Product (MVP). Defining an MVP ensures that development efforts focus on delivering a core, functional tool as efficiently as possible, avoiding feature creep and unnecessary complexity. While the MVP captures only the essential requirements, it is also important to document additional, non-MVP requirements early—even if only at a high level. These future requirements help in guiding architectural decisions, ensuring that the technology stack remains adaptable, and allowing for iterative refinement as the project evolves.
By keeping both the immediate MVP and longer-term vision in mind, you create a structured approach that balances rapid development with scalability and future-proofing.
2. Define Your AI Strategy
Placing this consideration second in this article isn’t about chasing trends; it reflects the transformative role AI can play in tools and IDEs. In many cases, AI drastically impacts efficiency and user workflows. In some scenarios, AI may even replace certain features or even entire use cases of a tool altogether.
It is therefore essential to decide early on whether AI will play a role in your tool or IDE and what the specific use cases will be. At a minimum, this decision will influence your UX concept and architectural design. For example, you might need to design mechanisms for providing contextual information to the AI or enabling AI to control certain parts of the tool. If AI can do certain steps or entire workflows of your tool’s use cases, you can focus your development effort, for instance, on a user interface optimized for reviewing the AI suggestions rather than allowing users to efficiently create changes themselves.
Successful AI integration often requires extensive data collection and user testing. Starting with proof-of-concept implementations early in the project increases your chances of success, as it provides indications of what is possible in which timeframe. This ensures your team avoids following the wrong path and helps you identify AI opportunities that might otherwise be missed.
To learn more about this topic, please have a look at:
👉 Talk: Enhancing Custom IDEs and tools with AI: Strategies, Use Cases, and Pitfalls
👉 Talk: Building AI-Powered Tools and IDEs: Practical Techniques
👉 Our service offerings to build tailored AI Assistance in Tools and IDEs
3. Decide on the Platform: Cloud, Web, Desktop, All of them?
Web-based technology stacks are now the de facto standard for tools and IDEs, even if they are still deployed as desktop applications. Desktop applications built with traditional “non-web” technologies, in contrast, are becoming legacy solutions and should only be considered in very specific cases.
If you are not familiar with web-based, cloud-based or in general with modern tool architectures and concepts, we recommend the following article for details:
👉 Modern (web-based) Tool and IDEs: Definitions, Concepts and Architecture
Additionally, if you want to learn more about these core advantages of web-based tools, have a look at this talk summarizing
👉 Web-based Tools and IDEs: Accomplishments and Opportunities .
And this talk about:
👉 Building Web-Based Tools and IDEs - Pitfalls and Best Practices
In a nutshell, web-based tools use web technologies and a browser component for rendering the user interface, but can still be deployed as desktop applications, while cloud-based tools are web-based tools deployed on a cloud infrastructure and accessed by a generic browser.
While cloud-based deployments are becoming more prevalent, many projects still provide desktop applications. The reasons for this include:
Developer preferences: Many developers are accustomed to desktop applications and prefer the familiarity and responsiveness they offer.
Local hardware integration: Tools that rely on local hardware can work in cloud environments but that often requires additional effort to integrate. Desktop applications simplify this by operating directly on the user’s machine.
Infrastructure and cost considerations: Hosting tools or IDEs online offers advantages like easy accessibility and central deployment but introduces the need for hosting infrastructure and processes, such as monitoring, authentication, authorization, billing, etc. This raises critical questions, such as whether the application will be hosted on-premise or as a SaaS offering and who bears the associated costs. Desktop applications, in contrast, leverage existing hardware and energy, avoiding these questions altogether.
Fortunately, with modern technology stacks, you don’t need to decide the deployment method on day one. You can build your tool in a way that keeps both desktop and cloud-based options viable. Even for projects that begin with a desktop deployment, maintaining a path towards deploying the application in the cloud as a future option is highly valuable. Over time, organizations can revisit and iterate on their deployment strategies as their needs evolve.
👉 Our service offerings for building Web- and Cloud-based Tools
4. Make, Reuse or Buy?
Before diving into the technical choices, take a step back and evaluate whether building a custom tool or tool extension is truly necessary. In many cases, leveraging an existing solution—whether through extension, adaptation, or integration—can significantly reduce effort and cost. Consider a “make, reuse, or buy” decision early on:
Make: If your use case is unique to meet your requirements or you need long term strategic control, building a custom tool from scratch may be the best approach.
Reuse: If there are existing open-source or commercial tools that cover most of your needs, extending, customizing and integrating them might be more efficient than reinventing the wheel.
Buy: If a commercial tool exists that aligns with your goals and offers the necessary extensibility, purchasing and customizing it could be the fastest path to value.
Only after making an informed decision to build a custom tool or extension should you determine the optimal platform. In the rest of this article, we assume you’ve determined that building a tool or extending an existing one is necessary.
5.Choosing the Right Foundation for Your Tool
Reinventing the wheel is rarely efficient, especially in the complex landscape of tool and IDE development. The effort required to implement tools is often underestimated. However, the basic requirements for tools frequently overlap—for example, concepts such as an editor, a file explorer, a flexible workbench, menus, toolbars, code editing capabilities, diagrams, terminals, property views, user settings, and packaging as both desktop and cloud applications. Additionally, modern tools increasingly rely on architectures that integrate protocol-based standards like the Language Server Protocol (LSP), Debug Adapter Protocol (DAP), Model Context Protocol (MCP), or Graphical Language Server Protocol (GLSP). Many also require advanced AI features, such as chat interfaces, context management, or large language model (LLM) integration.
Avoiding to build all these features from scratch, reusing an existing tool or platform as a foundation makes sense in most cases and provides the following benefits:
Time Efficiency: By utilizing existing components and architectures, you can accelerate development timelines and allocate resources to innovative aspects of your tool. Especially considering an MVP approach that prioritizes delivering something of value early on.
Maintainability: Regular updates and a strong community support ensure that the framework remains up-to-date with the latest technologies and best practices. This reduces the burden of maintenance on your team.
Ecosystem Integration: Frameworks like Eclipse Theia and tools such as VS Code have extensive plugin ecosystems (e.g. via VS Code extensions). This allows you to easily integrate third-party extensions, enhancing the functionality and flexibility of your tool, now and in the future.
When selecting a foundation for your tool, there are multiple options to consider:
Using a Tool/IDE Framework: Platforms like Eclipse Theia provide a modular foundation that allows you to build highly customized tools by leveraging prebuilt components. This approach avoids the need to create core functionalities from scratch and enables rapid development while maintaining flexibility.
Extending an Existing Tool: In cases where an existing tool such as VS Code or the Theia IDE closely aligns with your requirements, extending it with plugins or extensions can be an efficient approach. This approach enables you to build on a mature ecosystem while focusing on adding domain-specific or differentiating features. You will avoid the effort to deploy your own tool, but of course you will also have less control over the foundation of your offering.
Forking an Existing Tool: Forking tools like VS Code can provide complete control over the tool’s functionality and appearance. However, this approach is often resource-intensive, as it requires you to maintain the fork on your own, handle updates manually, and manage compatibility issues. See for example:
👉 Is Forking VS Code a Good Idea?
When selecting a foundation for your tool, consider the following:
Feature Alignment
Ensure that the framework or tool you integrate with supports as many of your tool’s current technical requirements as possible while providing mechanisms for addressing gaps through customization. For example, if your tool requires advanced AI features such as LLM integration or context management, verify that the framework offers these capabilities or can be extended to include them. Similarly, assess whether the framework can support specific deployment strategies, such as desktop, web, or cloud-based environments. Mapping your initial requirements—like editor functionality, file explorers, or integration with protocols such as LSP and DAP—against the framework’s built-in features will help identify gaps early.
UX Concept
Evaluate how closely the default UX concept of the base technology aligns with what you want to build. Frameworks like Eclipse Theia are flexible enough to be adapted to specific needs, while tools like VS Code are more limited in this regard. The closer your requirements align with a default UX, the lower your development and maintenance costs will be. However, consider trade-offs: in some cases, aligning with an existing UX may improve user adoption (e.g., using a default Theia or VS Code UX), while in other cases, a highly customized UX may better meet your users’ needs.
Customization
Evaluate how easily the framework can be tailored to meet unique requirements. If the base technology doesn’t natively support a key feature, determine whether it can be added through extensions or custom development without introducing unnecessary complexity. For example, modular frameworks like Eclipse Theia allow extensive customization through prebuilt components and APIs, making it easier to adapt the tool to domain-specific needs. Conversely, technologies that limit customization or lock you into specific workflows may hinder the tool’s ability to address evolving requirements over time.
Community and Support
A vibrant community and active maintenance are essential for addressing issues, keeping up with updates, and adopting best practices. Check the quality of support channels, such as forums, issue trackers, and documentation. Additionally, consider the availability of service providers who can assist with building your tool, adapting the underlying technology, and maintaining both your tool and its foundation. These providers can help accelerate development, reduce technical debt, and ensure long-term sustainability. This ensures that as your project grows, you can rely on timely and effective assistance.
See also the following related articles:
👉 Eclipse Theia vs. VS Code OSS
And our service offering for:
By carefully evaluating these considerations and mapping your current and anticipated needs against a framework’s capabilities, you can save valuable development time while ensuring scalability, flexibility, and ease of maintenance. Once you’ve selected a foundation technology, it’s time to validate your assumptions through proof-of-concept (PoC) implementations. This approach will allow you to test critical ideas early and refine your strategy for building the tool. (See the section below for more details.)
6. Select and Adopt Additional Technologies
Beyond selecting a foundational platform, you will likely need additional technologies to complete your tool or IDE. These may include a UI toolkit, a diagramming framework, a cloud-hosting solution, or extensions from the VS Code ecosystem. The key considerations for selecting these technologies are similar to those for choosing a foundation: alignment with your requirements, ease of customization, and long-term maintainability. However, compatibility is an additional crucial factor—new technologies must integrate seamlessly with your chosen foundation and deployment model.
Examples for additional technologies:
👉 Hosting tools in the cloud with Theia Cloud
👉 AI assistance in IDEs and tools
One particularly important aspect to evaluate is the maintenance and governance of the technologies you adopt. Open-source frameworks and third-party tools evolve, and ensuring ongoing compatibility and support is vital. Consider the long-term sustainability of your dependencies, including their update frequency, community activity, and governance model. Engaging with the communities behind these technologies or working with vendors who provide sponsored development long-term support can help mitigate risks and ensure a stable foundation for your tool. By actively participating in their development, you gain a level of influence that helps keep the goals of adopted technologies aligned with your own requirements.
👉 Our service offering for Sponsored Open Source Development
In some cases, a project may be very well maintained but controlled by a single stakeholder. While this can offer stability and quick decision-making, it can also limit your influence on the project’s future direction if that stakeholder’s priorities change. When strategically adopting such technology, be mindful of vendor-neutral governance models or communities that allow multiple stakeholders to shape the roadmap. This ensures that you retain the ability to guide an open-source project’s evolution in alignment with your tool’s long-term needs.
7. Build Proof of Concepts (PoCs)
Starting an IDE or tool development project is often fundamentally different from developing typical business applications. Unlike enterprise applications, which are frequently iterated upon and often have shorter lifecycles, tool development involves long-term investment and sustainability concerns. Even large companies usually do not start multiple tool projects annually unless their core business is centered around tool development, as it is for EclipseSource.
Given the specialized nature of tool development, it is crucial to begin with Proof of Concepts (PoCs) to validate your ideas, gain knowledge and ensure that the technical foundation aligns with your goals.
Advantages of Developing PoCs:
Risk Mitigation: Identifying potential technical challenges and user acceptance issues early can prevent costly setbacks later in the project.
User Feedback: PoCs provide a direct channel to gather feedback from real users, ensuring that development is aligned with actual needs.
Knowledge Building: Developing PoCs enables your team to build expertise in domain-specific challenges and applied technologies, ensuring a smoother transition to full-scale development.
Trust and Support Evaluation: If you involve external help, PoCs provide an opportunity to evaluate the quality of support you receive and build trust with external collaborators.
Iterative Improvement: PoCs enable you to test and refine concepts incrementally, fostering a culture of continuous improvement and adaptability.
Best Practices for Building PoCs:
Prioritize MVP and technically challenging features: Focus on the most critical features from a user perspective while simultaneously tackling the technically most complex aspects. This ensures early validation of usability while mitigating technical risks and evaluating the architecture.
Establish a direct feedback loop with end users: Engage real users as early as possible to validate assumptions, gather insights, and adapt the tool to actual needs. Direct user feedback is invaluable for refining functionality and avoiding costly misalignments.
By incorporating PoCs early in your development cycle, you can validate your ideas, refine your approach based on real user interactions, and set a solid foundation and team for building a successful tool or IDE.
8. Get the Right Team
Assembling the right team is pivotal to the success of your tool or IDE development project. Companies often have access to domain experts who deeply understand workflows and requirements. However, as previously mentioned, kicking off tool and IDE projects is often not their core business, but requires very specific technical knowledge and experience—usually not part of a typical developer portfolio. Therefore, it often makes sense to augment a team with tool specialists to ensure a strong technical foundation and efficient development.
Key Roles and Expertise:
Domain Experts: Individuals who possess a deep understanding of the end users’ workflows, challenges, and requirements. Their insights ensure that the tool addresses real-world problems effectively.
Tool-Building Experts: Developers and engineers skilled in the latest technologies, frameworks, and best practices for tool and IDE development. They bring the technical expertise and ecosystem oversight necessary to implement robust and scalable solutions.
UX/UI Designers: While this role is common in business application projects, it is often underestimated in tool and IDE development. Many assume that technical tools for experts do not require UX considerations, but a well-designed interface significantly improves efficiency. Additionally, designing tools and IDEs requires a very specialized UX skill set, as designers must immerse themselves in highly technical domains—an entirely different challenge compared to designing business applications.
Leveraging External Expertise:
Consultants and Partners: Engaging external consultants or partners can provide specialized knowledge, additional resources, and fresh perspectives, especially when tackling complex or niche challenges.
Community Engagement: Participating in developer communities and forums helps tap into a broader pool of talent and insights, enhancing the team’s capabilities and innovation potential.
Building the right team ensures that your tool or IDE is developed with both technical excellence and a deep understanding of user needs, paving the way for a successful and impactful product.
If you need help, EclipseSource is your tech partner for tool and IDE development, have a look at our services:
👉 Our service offerings for building custom tools and IDEs
👉 Our service offerings to building web- and cloud-based tools and IDEs
👉 Our service offerings to building AI-powered tools and IDEs
Conclusion
Building a custom tool or IDE is a complex endeavor, and while this article outlines key high-level considerations, every project comes with its own unique challenges. Many of the topics discussed here—such as defining the right foundation, integrating AI, or choosing the best deployment strategy—require careful evaluation in the context of your specific goals and constraints. However, keeping these aspects in mind provides a structured approach, helping to navigate the complexity and avoid common pitfalls.
At EclipseSource, we specialize in supporting organizations through the entire tool and IDE development lifecycle—from strategic planning to technical implementation. Whether you need guidance on architectural decisions, help with AI integration, or expert support in building web-based, cloud-based, or custom development tools, we’re here to help.
If you’re planning a tool or IDE project and would like to discuss your individual requirements, we’d love to hear from you!
👉 Get in touch with us to explore how we can support your journey toward a successful and future-proof tool!