Doubling Down on Open Source Tools and Phasing Out Defender

Following the successful initial launch of our Open Source Relayer and Monitor in April, and fueled by positive community feedback, we're doubling down on open source. Since the early days of OpenZeppelin, open source has been at our core—the OpenZeppelin Contracts library has empowered almost every blockchain developer to build secure smart contracts, enabling over $26 trillion in total value transferred, all at no cost to developers.

Now we’re dedicating our efforts to evolving Relayer, Monitor, and additional forthcoming development tools into open source, community-driven solutions that developers can fully control, customize, and seamlessly integrate into their workflows.

Because we believe these open source tools will outpace any hosted SaaS alternative, we're now officially announcing a phased sunset of the Defender platform, with its final shutdown planned for July 1, 2026.

At the same time, today we’re releasing a substantial update to our Open Source Relayer and Monitor, marking these tools as fully production-ready and representing a significant milestone in our open source roadmap.

Why We're Making This Change

Open source has always been at the heart of OpenZeppelin’s mission. By shifting our full focus from Defender to open source tooling, we aim to:

• Empower Developers: Open source tooling allows greater freedom to build bespoke infrastructure tailored to your specific operational needs, giving you the ability to run and manage it in your own environment.
• Accelerate Innovation: By building in public, these development tools will benefit from valuable community feedback and contributions, driving continuous improvements, integrations, and feature expansions more quickly.
• Rapidly Expand to New Chains: While Relayer and Monitor in Defender are limited to selected EVM network integrations, the open source versions are configurable with any EVM-compatible chain, as well as selected non-EVM networks. We've already expanded support to include Solana and Stellar, with additional integrations coming soon.

Ultimately, our vision is for these open source tools to provide a stronger, more sustainable foundation for onchain application security and reliability in the years to come.

Defender Sunset Timeline

• June 30, 2025: As of today, new user sign-ups have been disabled.
• July 1, 2026: The Defender platform will officially retire.

Until the final shutdown date, all existing Defender users will receive uninterrupted service, continued operational support, critical security patches, and the same high-quality reliability you've come to expect from OpenZeppelin.

For Defender Users: Migration to Open Source

We fully recognize the effort required in transitioning critical infrastructure. Our commitment is to minimize friction and maximize your confidence throughout the migration process. To ensure this, we’re providing extensive support, including:

• Detailed Migration Guidance: Soon we will publish comprehensive, step-by-step migration guides to facilitate a straightforward transition from Defender to the open source versions of Relayer and Monitor.
• Extended Parallel Testing Period: You have a full year to start using the open source tools alongside Defender, providing ample opportunity for your team to test, evaluate, and refine your new setup. You can make the full switch only when you are ready.
• Managed Service Offering: For teams preferring to delegate operational management, we offer customized Managed Service solutions, providing hosted infrastructure as well as deployment, monitoring, and maintenance of your Relayer and Monitor instances. If you are interested, please submit a request through this form.

For additional information, please visit our FAQ page, where you'll find answers to common questions and more details about the transition.

Build, Secure, and Operate with the OpenZeppelin Open Source Stack

To learn more about our comprehensive suite of open source tools—covering everything you need to Build, Secure, and Operate your onchain applications—we invite you to explore our newly launched Open Source Stack page.

Explore our Open Source Stack →

We remain deeply grateful to every Defender user who has trusted us to secure and streamline their blockchain operations. While we are now shifting our focus to open source development tools, we remain committed to delivering the same level of care throughout this transition.