Senior Software Engineer, Protocol

About the Company:

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 is responsible for fulfilling this mission in a decentralized way by imagining, building, and maintaining trustless systems that can scale to billions of people. One of the ways we do this is through a privacy-preserving protocol that powers World

ID using state-of-the-art cryptography. We are active in the Ethereum ecosystem, and work with the wider community to solve limitations around blockchain scalability. Our team builds Rust services deployed on Kubernetes clusters that generate and verify zero-knowledge proofs and interact with the Ethereum Blockchain and various Layer 2 solutions.

* This role is onsite based in our San Francisco, CA office

This is a unique opportunity to lead the development and roadmap of a critical component of our Protocol, enabling privacy  represents the first step in building a privacy-preserving digital identity ecosystem.

• Contribute to the development of performant and secure systems in Rust (or similar systems languages like C++).

• Collaborate with senior engineers and cross‑functional teams across cryptography, blockchain, AI, and hardware to build scalable solutions.
• Write clean, well‑documented, and well‑tested code.
• Participate in design discussions, code reviews, and iterative development cycles.
• Support the team in deploying and maintaining services in production environments.

• 4+ years of professional software engineering experience, including at least 2 year working with or learning Rust (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 bring some exposure to areas like distributed systems, protocols, cryptography, or blockchain—or you’re eager to grow in these domains.
• You thrive in a collaborative environment and are comfortable working closely with both engineering and non‑engineering stakeholders.
• 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

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Pay transparency statement (for CA and NY based roles):

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. In addition, TFH offers a wide range of best‑in‑class, comprehensive and inclusive employee benefits for this role including healthcare, dental, vision, 401(k) plan and match, life insurance, flexible time off, commuter benefits, professional development stipend and much more!

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