SDK generators are revolutionizing the way developers approach API integrations. These powerful tools automate the creation of software development kits (SDKs), eliminating the repetitive and time-consuming task of writing boilerplate code. By doing so, they enable developers to focus on building features and solving real-world problems rather than dealing with the complexities of manual SDK creation.

In this post, we’ll take a deep dive into SDK generators — what they are, how they work, and the key features that make them indispensable in modern software development. We’ll also discuss their numerous benefits, from accelerating project timelines to reducing errors, and how they contribute to a more seamless developer experience. Whether you’re a solo developer or part of a large team, SDK generators can help you save time, enhance efficiency, and deliver better products faster.

Let’s explore why SDK generators are game-changers and how they’re transforming the way we build and integrate APIs.

What to Look for in SDK Generators

There are several factors to evaluate when looking for an SDK generator. Here are some standard requirements that I’ve considered while reviewing SDK generators on the market.

• CLI capability: As developers, the terminal is our home. Mastering the ability to generate and automate tasks through the CLI empowers us to work smarter, faster, and with more confidence.
• SDK and documentation generation combined: Generating an SDK without proper documentation is like building a bridge to nowhere. Users need clear, accessible documentation seamlessly integrated with SDKs to unlock its potential.
• Smooth developer experience without too many screens: We aim for a quick and seamless experience. While additional screens may offer more customization, in most cases, they can be consolidated into fewer screens with well-organized parameters, enhancing usability without sacrificing flexibility.
• A single installation (no other libraries to install): A good SDK works right out of the box. Requiring additional packages or setups undermines the goal of delivering a seamless developer experience.
• No configuration issues and quick setup: The best user experience when generating an SDK is straightforward: upload your OpenAPI definition, fill in a few parameters, and you’re good to go. Clear instructions and a quick setup are key. Dealing with unexpected configuration issues can be frustrating and often drives developers to explore alternative solutions.

1. Fern

2. APIMatic

The SDK creation process with APIMatic was incredibly smooth and intuitive, making it a truly enjoyable experience. What impressed me most was the ability to generate both SDKs and documentation in a single step, streamlining the workflow and saving valuable time. This seamless integration of tasks enhanced the overall user experience and highlighted the tool’s focus on efficiency and developer convenience. I genuinely appreciated how effortless and well-designed the entire process felt.

3. OpenAPI-Generator

Using OpenAPI-Generator, the SDK creation process was straightforward and intuitive, but integrating it into a test script proved to be more challenging than expected. The source code felt overly complex, requiring extra effort to make things work. On the positive side, the documentation generation was reliable and covered most use cases. It produced an HTML page containing all the necessary information about the SDK, though it lacked any notable formatting or design enhancements.

4. Stainless

The SDK generation process with Stainless was seamless, and the added feature of pushing the generated SDK to GitHub, complete with usage examples, was a great touch. The SDK is stored in a private repository within their organization, which can easily be transferred to a production repository. However, the absence of generated documentation for the SDK was a bit of a letdown.

5. Speakeasy

The setup process using Speakeasy was relatively straightforward, though navigating through several screens felt a bit cumbersome and slowed things down. Finding the generated documentation also took longer than expected, as it wasn’t immediately apparent where it was located. That said, the documentation was indeed available once I tracked it down, which ultimately made the effort worthwhile.

6. Kiota

Using Kiota felt more complicated than it needed to be, as it required installing multiple additional Python packages just to get started. On top of that, I found the test script structure to be unintuitive and not particularly user-friendly, which added to the frustration. The most significant drawback, however, was the lack of documentation for the generated SDK. Without proper documentation, it became harder to make the most of the tool’s capabilities, which was disappointing.

7. AutoRest

Lastly, I tested AutoRest. The missing operationId tags in the OpenAPI spec initially caused some frustration and wasted time, but once that was resolved, the process proceeded smoothly. Testing the generated SDK did require installing an additional library, though it wasn’t a significant hurdle. Unfortunately, similar to Kiota, I was unable to find a way to generate documentation for the SDK, which was a major drawback.

8. LibLab

When I loaded the OpenAPI spec into LibLab, I encountered a warning: “Operation must have a ‘non-empty’ tags array.” While it caught me off guard at first, it turned out to be just a minor notice. The SDK generation process itself was impressively fast, and installation was seamless. What I appreciated most was that the documentation was generated alongside the SDK, eliminating the need for any additional steps.

My Top Choice

After evaluating a wide range of tools, two stood out above the rest: Fern and APIMatic. Both platforms excel in delivering an exceptional user experience, high-quality SDK generation, and well-structured documentation. However, their approaches to achieving these results are quite distinct, offering unique strengths depending on your specific needs.

For me, the balance between SDK quality and documentation is critical. Clear and concise documentation ensures developers can get started quickly, while a reliable and well-structured SDK saves time and prevents headaches during implementation. If I had to choose between the two, Fern would be my top pick for SDK generation.

What sets Fern apart is the impeccable quality of its generated code. It’s clean, well-organized, and gives the impression of being hand-written with precision and care. Beyond aesthetics, the code is idiomatic and typesafe by default, which means it aligns perfectly with the best practices and conventions of the target language. This not only makes the SDK easier to use but also ensures greater reliability and maintainability in the long term.

Another standout feature of Fern is its attention to detail. From how it handles edge cases to the way it ensures compatibility across environments, everything feels thoughtfully designed. For developers who value high-quality tooling that minimizes friction and maximizes productivity, Fern offers a truly compelling solution.

That said, APIMatic also deserves recognition for its powerful customization options and robust documentation tools, which make it an excellent choice for teams with specific or complex API requirements. Ultimately, both tools are fantastic, but for those who prioritize clean, idiomatic, and typesafe SDKs, Fern is hard to beat.