Senior Software Engineer (Passkeys)

Bitwarden promotes better internet security and safety with the leading open source password management solution for individuals, teams, and business organizations. Our philosophy on security is that “we are all in this together” – we continue to offer a full-featured free version of Bitwarden so that everyone can be protected with strong password management. We also provide enterprise-grade solutions to some of the largest companies in the world, and will continue to innovate in the identity and authentication market as the world starts to grow beyond passwords. Read more on the Bitwarden blog. 

As a Senior Engineer on the Passkeys team, you will build the technology taking the world beyond passwords. Bitwarden is a credential provider across browser, desktop, and mobile, and the Passkeys team owns our implementation of WebAuthn and FIDO2 — creating and asserting credentials, integrating with each platform's credential provider APIs, and the emerging standards for moving credentials between providers so that users are never locked in.

This is a low-level, cross-platform engineering role. The work is written primarily in Rust, in the shared SDK consumed by every Bitwarden client, where you will implement specifications requiring a robust attention to detail -  a subtle misreading of the requirements produces edge-case user login errors in certain use cases. The WebAuthn and passkey space is constantly evolving as well, so you will be responsible for understanding how the specification is changing, how our credentials are being used on client sites, and how to adapt to these changes in our core SDK.

RESPONSIBILITIES

• Design, build, and maintain Bitwarden's implementation of the WebAuthn and FIDO2 standards, including credential creation, assertion, and storage within an end-to-end encrypted vault
• Integrate our passkey implementation with each platform's credential provider surface across Bitwarden's clients
• Implement and help shape emerging standards for credential portability and secure import and export between providers
• Build the interoperability testing that keeps our implementation correct against the long tail of relying parties, browsers, and platforms our users encounter in the real world
• Become an expert on the Bitwarden APIs and the cryptographic and architectural constraints of a zero-knowledge product
• Participate in code reviews, learning, and spreading technical knowledge
• Independently plan, estimate, and deliver new feature work and bug fixes
• Occasionally review & approve bug fixes submitted by the user community

WHAT YOU BRING TO BITWARDEN

• Deep working knowledge of WebAuthn and the FIDO2/CTAP stack
• Expertise and demonstrated experience in applied cryptography
• Experience in native OS development and integration with platform-level APIs, including MacOS, Windows, and Linux
• Experience with developing cross-platform core SDKs and managing FFI boundaries, preferably in Rust
• Experience implementing a standard or protocol from its specification, and the discipline that requires — reading the spec closely, handling the edge cases, and testing against real-world implementations rather than assuming conformance
• Familiarity with authentication and identity systems
• A rigorous approach to correctness — you write readable, testable code, and you think carefully about failure modes in software that handles sensitive data
• Experience using AI tooling in your development and testing workflow (Anthropic Claude preferred)
• Collaborative and adaptable mindset
• Openness and authenticity combined with excellent communication skills
• Excitement and enthusiasm for open source and for better internet security 
• Excellent problem-solving skills – you might not know all the answers, but you know how to find and communicate the solution

WHAT TO EXPECT IN THE INTERVIEW PROCESS

• Interview with our Recruiting Manager
• Interview with the hiring manager
• Panel interview with other engineers
• Reference calls

A FEW REASONS TO WORK WITH US

• Our user community loves us and we love them. Come to work each day with a sense of purpose as we bring a more secure internet experience to everyone from our friends and family to the world’s largest organizations.
• Become an expert. You’ll get immersed in the prominent technology markets of security and open source software.
• We are dedicated to building a diverse and talented team. Work remotely with motivated and supportive team members across the world.
• Learn and grow. Take on new challenges with the support of your team, and join our #growth-club to continue personal and professional development. 
• At Bitwarden, we are passionate about what we do, but not necessarily everything we do. Our engineering team makes it a policy to carve out some time for personal growth, learning, skill building and pursuing personal passions that positively impact the team and company. To ensure that everyone has time to reaffirm their purpose and grow, you are encouraged to self-direct up to 15% of your week to what you feel is important for the company and for yourself.

Equal Opportunity Employer

We are committed to fostering an inclusive workplace where everyone can do their best work. We welcome applicants from all backgrounds and make employment decisions based on skills, experience, qualifications, and business needs.