Introducing Block Open Source

Today, we’re launching Block Open Source, an Open Source Program Office that serves as the central hub of expertise for our open source strategy and operations.

At Block, engineering is at the heart of everything we do. From developing seamless payment solutions to creating new tools for financial inclusion, our engineers are not just building products, they're shaping the future of financial services and more. Since the founding of the company, open source has been central to what we do.

Open source software and open standards offer significant advantages to all. For our customers, it provides transparency, enhanced security, and freedom from vendor lock-in, ensuring better interoperability and higher-quality systems. For engineers, open source fosters rapid innovation, higher-quality technology, and increased security and reliability through relentless collective peer review. Additionally, it allows engineers to build on existing work, enhances the company's engineering culture, and raises talent density. Importantly, by allowing others to build on our open source technology, we create pathways for new solutions that drive economic empowerment — Block’s ultimate purpose.

Since the founding of the company, Block has always encouraged and supported our engineering teams to consume from, contribute to, and create open source projects. We’ve made notable contributions to the Android Open Source Project (AOSP), Envoy, Golang, Jetty, Kubernetes, MySQL, Netty, Pytorch, Tensorflow, Terraform, TiDB, and more. Further, we’ve launched or co-launched several open source projects of our own, many of which are highly impactful within their respective domains. Some examples of Block’s open source successes include:

OkHttp is a modern, fully featured HTTP client for Java and Kotlin, that supports HTTP/2, compression, response caching, and connection pooling. Because of its popularity, it has become the default client included in the Android operating system.

Retrofit is a higher-level library built on top of OkHttp. It simplifies the process of interacting with REST APIs by automating the creation of network calls and parsing responses into Java objects. It is widely adopted by the Android community for simplifying network operations.

gRPC is a high performance language-agnostic RPC framework for communication between client and server, and between services, built on the HTTP/2 protocol. gRPC was born out of open collaboration between Block (then Square) and Google, and has grown to become a worldwide standard, with many other popular open source as well as commercial infrastructure frameworks leveraging it.

LeakCanary is the most widely used tool for automated memory leak detection in Android apps and is a de-facto standard. Its ease of use and real-time analysis make it a go-to tool for developers.

Lightning Development Kit (LDK) and Bitcoin Development Kit (BDK) are modular, lightweight libraries that simplify developing Lightning and bitcoin applications such as wallets. Built to cater to a diverse range of use cases, they bridge the gap between bitcoin’s complexity and developers’ need for ease of use and security.

Bitkey and Proto’s mining hardware are examples where source code is made publicly available to allow independent auditing. This fosters trust among users and the broader bitcoin community, as developers and researchers can verify the integrity, security, and functionality of the hardware and software.

Model Context Protocol: Block collaborated with Anthropic and others to launch the Model Context Protocol — an open standard helping AI agents securely connect to the systems and data they need to provide real-world outcomes.

With the launch of our new Open Source Program Office, we aim to apply a consistent strategy to our open source work, which will ensure a high standard of quality for our projects and support for their communities, as well as deeper relationships with open source foundations and open standards bodies.

We are beginning by rolling out several initiatives today, including:

• A dashboard to monitor the health of our open source projects, to allow us to focus attention and resources where they are needed most.
• An open source donation program in conjunction with Thanks.Dev, to ensure we support the maintainers of key open source technologies that we rely on. We recognize that we’re “standing on the shoulders of giants” — either directly or indirectly.
• Consolidate and strengthen relationships with open source foundations and standards bodies, to ensure ongoing and long-term support, engagement, and alignment with our needs.

Additionally, we’re exploring more initiatives to accelerate our open source culture, for example:

• Education: Providing resources focused on open source best practices, featuring successful projects as case studies, to help engineers and managers at Block navigate the open source landscape. We’re also working on frameworks that will help evaluate whether a project is suitable for open source, and quantify resourcing for their sustained development. This will help ensure resources are available to maintain a bar of quality for our open source work.
• Mentorship: Piloting an internal mentorship group for new maintainers at Block, offering them guidance and support from seasoned peers. This also fosters collaboration amongst an internal community of maintainers.
• Developer Advocate Program: Maintaining high-quality open source projects can be challenging, especially for smaller teams that may not have expertise in community building. We’re exploring a number of ways to offer support, including where teams have access to a group of developer advocates to assist with community engagement and triage, enabling maintainers to focus on core developments and improvements. 
• Advocating for Open Standards: Block is a proud and committed participant in numerous industry standards organizations. By investing in open standards, we are working to advance a more collaborative, interconnected financial ecosystem that benefits all.
• Open Source Project Directory: A searchable directory to promote visibility and discoverability of Block’s open source projects, with links to related articles, examples, and documentation, as well as good first issues that people can use to connect with the community.

These initiatives underscore Block’s long-term commitment to the open source community, within our walls and beyond. Open source technology fuels company growth by fostering innovation, collaboration, community engagement, and quality, while enabling the development of scalable, secure, and cost-effective solutions. This drives economic empowerment for individuals and businesses alike.

To learn more about Block’s open source work and keep up with our progress, you can visit block.xyz/open-source or:

Twitter/X

LinkedIn

Discord