Membrane Open Source API Gateway

Why Trust Matters

Open source infrastructure software offers many advantages. This page explains important aspects specific to API gateways and what you can expect from Membrane as a representative open source API gateway. It outlines advantages and provides practical arguments you can use to support an internal decision.

1 True Open Source

Open source licenses provide different levels of freedom. They range from source-available models with restrictions to permissive open source licenses that allow commercial use without significant limitations.

Many popular API gateways follow an open core model, where only part of the functionality is open source. A community edition offers basic features, while essential capabilities such as mTLS or JWT signing are only available in a paid enterprise edition.

Membrane is fully open source. There is no separation into community and enterprise editions. All features are available in a single, complete distribution.

2 Open Source Support

Open source does not mean there is no vendor or no support. Many open source projects are backed by commercial companies that provide professional services, support, and consulting for customers who rely on the software.

You can use Membrane free of charge without functional limitations. If the gateway becomes part of critical business processes, professional support can provide additional confidence. Support options include assistance with setup, troubleshooting, performance tuning, and security-related topics. You and your team can decide if and which level of support you want to purchase.

3 Why You Should Use an Open Source API Gateway

There are many reasons to prefer an open source API gateway over a closed or partially open alternative. Which arguments matter most depend on your environment, regulatory requirements, and industry.

Beyond the points listed below, the strongest argument is the product itself. Invest an hour to download Membrane and explore it by working through the tutorials. Hands-on evaluation is often the most effective way to make an informed decision.

3.1 Trust Only Open Source API Gateways

An API Gateway is a critical part of security infrastructure. It handles authentication, authorization, and traffic control for every API call that enters your company. Organizations rely on it continuously, which makes trust and transparency essential when choosing a gateway.

Open source API gateways provide transparency because the source code is publicly available for review. Developers and independent researchers can audit the implementation, identify vulnerabilities, and verify that no hidden backdoors or undocumented access mechanisms exist. Today, automated analysis tools and AI-based code review agents scrutinize every pull request before it is merged.

With proprietary software, the internal implementation is not visible. Organizations must rely on vendor assurances and external certifications. This creates a trust dependency and makes it harder to independently verify the absence of hidden functionality, privileged access paths, or undisclosed telemetry.

Open source does not automatically guarantee security, but it enables independent verification, faster vulnerability detection, and greater long-term trust. For security-critical components such as an API gateway, transparency and auditability are strong advantages.

3.2 Digital Sovereignty And Open Source

Digital sovereignty has become an important topic in Europe, particularly in countries such as Germany and France. Organizations increasingly want to reduce dependencies on infrastructure software controlled by foreign vendors or subject to foreign jurisdictions. When critical components like API gateways are operated by third-party vendors, this can create long-term strategic and regulatory dependencies.

Open source software is often seen as a key building block for digital sovereignty. Access to the source code allows organizations to run the software independently, audit its behavior, and maintain or fork it if necessary. This reduces reliance on a single vendor and provides more control over security, deployment, and long-term operation.

For security-critical infrastructure, such as API gateways, the ability to operate the software independently and avoid vendor lock-in is an important factor. Open source enables organizations to retain control over their systems even if geopolitical conditions, licensing models, or vendor strategies change.

3.3 Community

Healthy communities form around active open source projects. Users can open issues, request features, and discuss ideas directly with the maintainers. Contributions such as pull requests, documentation improvements, and bug reports are welcome and help shape the direction of the project.

This open collaboration model ensures that real user requirements influence development. Features are driven by practical use cases, bugs are discovered earlier, and improvements are shared with everyone. A strong community also increases transparency, long-term sustainability, and trust in the software.

You are welcome to join our community at the GitHub site.

3.4 Easier Automation And GitOps

Some commercial API gateways and API management solutions are closed or semi-closed systems. They do not allow storing the full configuration and setup as text in a source repository such as Git, which limits automation and reproducibility.

Membrane API Gateway uses YAML or XML configuration files that can be stored together with OpenAPI definitions, JSON Schema, and other artifacts in Git. This enables the application of DevSec and APIOps principles to API gateway management.

The entire process, from API design with OpenAPI to deployment on the gateway, can be versioned, reviewed, and automated through CI/CD pipelines. Git-based workflows also make it easy for teams to collaborate without requiring proprietary tooling or vendor-specific platforms.

3.5 No Vendor Lock-in

With proprietary software, you are dependent on the vendor. If the product is discontinued or no longer maintained, you may not receive updates, patches, or new features. This creates a risk for long-term infrastructure components such as an API gateway.

Open source software reduces this dependency. If development slows down or stops, the code can be forked and maintained by your organization or by the community. Well-known examples include MariaDB, which emerged from MySQL, and LibreOffice, which was forked from OpenOffice.

Organizations typically prefer actively maintained projects, but open source provides an additional safety net. Even if a project is no longer actively developed, it can continue to run, be maintained internally, or be revived by a new community.

3.6 Full Control Over Security

Real open source software is fully transparent. In the event of a security vulnerability, you and other members of the community can analyze the code to understand potential impact and exposure. During incidents such as Log4Shell, users independently reviewed their dependencies and verified whether their deployments were affected, even while we as maintainers were still performing our analysis.

With open source, you are not entirely dependent on a vendor to provide a fix. While most organizations prefer to use officially supported releases, it is possible to update a dependency, apply a temporary patch, or implement mitigation measures yourself if required. This additional control can be important for security-critical infrastructure where time is critical.

Open source does not mean operating without support. Commercial support options can provide proactive security notifications, vulnerability assessments, and assistance during incident response. This combines the transparency of open source with the reliability expected from professionally supported infrastructure software.

3.7 Deploy Anywhere

Some vendors require cloud-based deployment models or hosted control planes. This creates ongoing licensing costs and gives the vendor control over how and where the gateway is operated. It can also introduce constraints for regulated environments, private networks, or air-gapped installations.

An open source API gateway allows you to deploy according to your requirements. Run it on-premise, in containers, on Kubernetes, at the edge, or in any cloud environment. This flexibility is important for hybrid architectures, data residency requirements, and security-sensitive deployments.

Your operational and architectural requirements should determine where the API gateway runs, not vendor-imposed deployment or licensing models.

3.8 Cost Transparency

API gateways can become cost traps when pricing is based on requests, CPU cores, or premium features. What initially looks affordable can become expensive as API traffic grows. Organizations often underestimate how quickly API usage increases once more services, clients, and automation rely on the gateway.

When both business traffic and licensing costs scale together, budgeting becomes difficult. Open source API gateways avoid this problem because costs are primarily tied to infrastructure and operations, not to request volume or enabled features.

Core-based licensing can also influence architecture decisions. It often encourages centralized deployments, because running many smaller gateways across teams or environments becomes expensive. This can limit scalability and flexibility.

Open source software removes licensing constraints and allows you to choose the deployment model that best fits your architecture, whether centralized, distributed, or hybrid. Your architecture should define your deployment, not the licensing model.

3.9 Transparent Performance Characteristics

If an API gateway does not provide the expected performance, open source software allows you to analyze the behavior in detail. You can attach a profiler, inspect thread usage, review connection handling, and identify performance hotspots directly in the code.

The results can be used to optimize configuration, adjust deployment settings, or create a patch that removes the bottleneck. This level of transparency makes performance tuning more predictable and avoids reliance on vendor support for diagnosing critical issues.

3.10 Long-Term Sustainability

The software market is subject to consolidation. Companies acquire competitors, product portfolios are merged, and older products are often discontinued. Customers may then be forced to migrate to a different platform, which can invalidate previous investments in architecture, configuration, and operational knowledge.

This risk is particularly relevant for products backed by venture capital, where acquisitions are a common exit strategy. After an acquisition, priorities, licensing models, or product roadmaps may change.

Open source software reduces this dependency. Even if ownership changes, the software remains available and can continue to be used, maintained, or forked. This protects long-term infrastructure investments.

Membrane has been developed by predic8 without venture capital and is funded through services and support. The focus is on long-term product stability rather than growth targets or acquisition strategies. This supports a sustainable development model for critical infrastructure software.

3.11 Artificial Intelligence Support

Artificial intelligence has become a standard tool in daily IT work. When using open source software, AI tools can analyze the actual code base to provide more precise assistance. Developers can ask AI systems to explain behavior, suggest configuration changes, identify bugs, or generate examples based on the real implementation.

Typical tasks where AI benefits from open source code include:

With proprietary software, AI systems must rely primarily on documentation, blog posts, and limited examples. Access to the full source code enables deeper analysis and typically results in more accurate answers, faster troubleshooting, and better developer productivity.

4 Why Is Membrane Open Source?

We have relied heavily on open source projects such as Apache Camel, Kafka, Artemis, and the Spring Framework. Over time, we came to appreciate the ability to inspect the source code, understand how a system works, and fix issues ourselves when needed.

Sharing Membrane as open source is a deliberate strategy. Instead of investing heavily in marketing or venture-funded growth, we focus on building a solid product and rely on users to spread the word. This allows us to concentrate on improving the API gateway itself rather than optimizing for sales processes. In addition to the software, we also provide an API gateway eBook and educational content on YouTube.

I learned software development in open source communities during the early days of the Apache Software Foundation. By fixing bugs and contributing documentation, I eventually became a committer. Today, contributing to open source is much more accessible. Platforms like GitHub make collaboration straightforward. Anyone can create a pull request, and well-prepared contributions with tests and documentation have a high chance of being accepted.

Membrane has also benefited from valuable contributions from the community. We appreciate every pull request and the ongoing collaboration.

4.1 Open Source Drives Innovation

A common principle in open source development is to release early and release often. This allows users to test new features sooner, provide feedback, and influence the direction of the project. Improvements can be discussed publicly and integrated quickly into the codebase.

This collaborative development model often accelerates innovation. New ideas emerge from real-world use cases, and features evolve based on practical requirements instead of predefined product roadmaps. Bugs are discovered earlier, and enhancements are shared with the entire community.

Membrane followed this path from the beginning. The first versions date back to 2005, when the project started as a REST and SOAP debugging tool called SOAP Monitor. Users began deploying it in the DMZ to securely route requests into internal systems and requested additional security and routing capabilities. Based on this feedback, the UI was removed, the focus shifted to gateway functionality, and the architecture evolved step by step into a full API gateway.

Since then, community feedback and real-world usage have continuously driven the development of Membrane, including several architectural redesigns leading to the current version.

Several capabilities that are now found in some modern API gateways appeared early, and in some cases first, in Membrane. These include WSDL and OpenAPI validation, response validation, JWT signing at the gateway, as well as OpenAPI and WSDL rewriting.

4.2 How Open Is Membrane?

Membrane is distributed under the permissive Apache 2.0 License, allowing a wide range of use cases, including commercial products built on top of the code. Some vendors have even built their own solutions based on Membrane, which became visible through stack traces containing Membrane-specific exceptions.

5 Conclusion

The decision between open and closed source should not be based on cost alone. While open source eliminates license fees, it also offers benefits such as transparency, flexibility, and independence. For organizations with limited budgets, it can be an accessible starting point, but its value goes far beyond cost savings.

Investing in open source can also mean contributing to a community and building a partnership with the maintainers of the software. Choosing an API gateway should be based on long-term technical and strategic considerations, not just on licensing costs.

6 How to Convince Your Boss to Use an Open Source API Gateway

You may already see the advantages of using a truly open source API gateway, but adopting new infrastructure often requires management approval. Share this article to explain the benefits, including transparency, independence, security, and long-term cost control.

Decision-makers typically focus on risk, support, and sustainability. A mature open source API gateway addresses these concerns by offering auditability, no vendor lock-in, flexible deployment options, and optional commercial support. This combination provides both technical freedom and operational reliability.

If you need help convincing stakeholders, I can provide technical arguments, comparison material, and architecture guidance tailored to your environment. Contact me to discuss whether Membrane fits your requirements and how to present it internally.

Thomas Bayer API Architect

Thomas Bayer

Founder of Membrane API Gateway

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