Senior Backend Engineer: PHP/Rust for Privacy-First Libraries

Proton; Greater London; On-site; GBP 90,000 - 130,000; Full time

Benefits offered by this job

Stock options

Flexible working

Health coverage

Lunch and snacks

Transport support

Learning & development

Job summary

Proton is seeking a backend engineer to design and build shared libraries and internal services used across Proton products. You will shape architecture, write clear documentation, and collaborate with product teams to drive adoption in a fast-moving, privacy-focused environment.

You will work on a large-scale PHP backend with Rust components where performance and memory safety are critical, participating in RFCs and cross-team reviews while improving build times and developer experience.

Qualifications

• 5+ years building and operating backend systems in production.
• Working knowledge of Rust, or ability to learn quickly.
• Genuine taste in API design and ownership decisions of libraries vs services.
• Experience with codebases that are large enough for module boundaries to matter.
• Security-minded approach to abstractions and misuse.
• Ability to evolve shared code without breaking dependents.

Responsibilities

• Design and build shared libraries, framework layers, and internal services used across Proton products.
• Turn recurring patterns into good abstractions.
• Write documentation and examples people actually use, and treat adoption as part of shipping.
• Improve the day-to-day: build times, local dev setup, test ergonomics, debuggability, developer experience.
• Work in the open with product teams—RFCs and design reviews, occasional PRs between repos.
• Work closely with other developers to help integrate libraries seamlessly into applications.

Skills

Backend development

PHP

Rust

API design

Monorepo

Security mindset

Architecture

Job description

Proton is seeking a backend engineer to design and build shared libraries and internal services used across Proton products. You will shape architecture, write clear documentation, and collaborate with product teams to drive adoption in a fast-moving, privacy-focused environment.

You will work on a large-scale PHP backend with Rust components where performance and memory safety are critical, participating in RFCs and cross-team reviews while improving build times and developer experience.