Software Developer, Cryptography & Full-Stack

The role

We need a genuine all-rounder to help us execute faster across a broad, fast-moving product. You'll help with extending our pilot products (apps, SDKs and browser extensions), deepening our identity-provider integrations, and bringing fresh cryptography and signal-processing thinking to the protocol. You'll work closely with our CTO, including on offline, air-gapped systems as part of our critical-infrastructure project.

What you'll do

● Build and harden core product across the stack (Node.js/Express services, JavaScript front-ends, Chrome extensions)

● Work on our authentication protocol, including replay/relay resistance and key handling

● Develop SDKs, browser extensions and cross-browser support

● Integrate with identity providers via OIDC and WebAuthn/passkeys. One Identity today, with Okta and Microsoft Entra on the roadmap

● Contribute to our offline peer-to-peer authentication and its cryptographic protocol

● Help keep everything secure and scalable as we grow

What we're looking for

● Strong all-round engineer: excellent full-stack ability (JavaScript/Node.js, browser front-ends and extensions), and the ability to pick up new domains fast. This is the core of the day-to-day.

● Applied cryptography: solid working knowledge of key handling, hashing, replay/relay and protocol basics; you use crypto libraries correctly and think about threat models.

● Mobile development: you've built and shipped mobile apps or SDKs (native or cross-platform); a lot of what we do lives on the device.

● Signal processing: comfortable with the fundamentals (familiar with how audio is sampled and framed).

● Comfortable with IdP/SSO integration (OIDC, WebAuthn/passkeys)

● An eye for scalability and secure-by-design

Nice to have

● Embedded or OT exposure

● A security background or relevant certifications

Can be based in London or Manchester