Senior Software Engineer, Protocol

Rust Backend Engineer, Protocol role at World — onsite in San Francisco, CA. This position contributes to the core World ecosystem, including World  World Chain, by designing and implementing production-grade systems at the edge of cryptography, Ethereum/L2s, and zero‑knowledge.

World is a network of real humans, built on privacy-preserving proof-of-human technology, and powered by a globally inclusive financial network that enables the free flow of digital assets for all. It is built to connect, empower, and be owned by everyone. This opportunity would be with Tools for Humanity.

The Protocol team at TFH consists of engineers focused on shipping production-grade systems at the edge of cryptography, Ethereum/L2s, and zero-knowledge. We design and implement trustless, decentralized, and privacy-preserving systems that scale to billions of users. Our work powers World , World Chain, and other protocols within the World ecosystem, pushing the boundaries of what’s possible with decentralized identity and blockchain scalability.

We regularly collaborate with leading teams in the Ethereum ecosystem and contribute to open research and protocol design.

In this role, you will work on the core protocols that power the World ecosystem, including services that support World , World Chain, and related systems. You will contribute to design and implementation of existing software and engage in protocol-related efforts exploring the cutting edge of blockchain scalability. This is a highly collaborative role where you will often work closely with other TFH teams to build mission-critical services at the foundation of the World ecosystem.

• Write clean, efficient and maintainable code in Rust.
• Design and implement production-ready services to support the World ecosystem.
• Collaborate with teams across cryptography, blockchain infrastructure, AI, and hardware to deliver robust and scalable solutions.
• Own features from design to deployment.
• Contribute to technical planning, implementation, and code reviews throughout the development lifecycle.
• Contribute to the deployment, monitoring, and long-term maintenance of services in production.

• 5+ years of professional software engineering experience, including at least 2 years working with Rust in production environments (or significant experience with C++/Go and a strong interest in Rust).
• You’re excited about solving complex problems and working on systems that require high performance, scalability, and security.
• You have a T-Shaped skill set with exposure to areas like distributed systems, cryptography, or blockchain.
• You thrive in a collaborative environment and are comfortable working closely with both engineering and non-engineering stakeholders.
• You have strong written and verbal communication skills and can clearly articulate technical concepts to a range of audiences.
• You are naturally curious and value learning as much as shipping.
• You care deeply about code quality, learning, and building technologies that can have real-world impact.

• An open and collaborative office space in downtown SF
• Unlimited PTO
• Monthly Phone Reimbursement or a company device
• Daily in-office meals
• Top-tier medical, dental, vision insurance
• 401k + employer match program

The reasonably estimated salary for this role at TFH ranges from $184,000 - $230,000
, plus a competitive long term incentive package. Actual compensation is based on factors such as the candidate's skills, qualifications, and experience. TFH offers a wide range of healthcare, dental, vision, 401(k) plan, life insurance, flexible time off, commuter benefits, professional development stipend and more.

By submitting your application, you consent to the processing and internal sharing of your CV within the company, in compliance with GDPR.

• Mid-Senior level

• Full-time

• Engineering and Information Technology

• Technology, Information and Internet