Description
Summary Mozilla is building a position in open source AI through research, community, tooling, and public advocacy. A big part of that work is showing, not just telling. We need an engineer who ships fast and in public — working code and real demos that developers can install, fork, and build on. The current focus is Harbor , a Firefox and Chrome extension implementing a proposed Web Agent API that puts model choice, tool permissions, and agent oversight back in the hands of the user and the browser, rather than the vendor. Harbor is three layers: the browser extension at the bottom managing permissions, model access, and revocation; the SDK/API layer on top exposing primitives like window.ai , window.agent , and WebMCP tools; and the application and workflow layer at the top — the actual experiences being built. The thesis is that agents should only be able to do what a page explicitly declares, not free-roam the DOM. Making those layer boundaries legible is core to the role — if a developer or their coding assistant keeps reaching for the wrong primitive, that's yours to fix. If you've shipped a browser extension, authored MCP servers, run models locally with Ollama or llama.cpp, and thought seriously about prompt injection as an architectural problem rather than a prompt-level concern, this is the specific intersection we're hiring for. Beyond Harbor, Mozilla is building across a broader sovereignty stack — open identity, privacy-preserving verification, and other surfaces where the same thesis applies: users should own the layer, not the platform. The right person will find adjacent prototyping work as that develops, and will be energized by the problem space broadly enough to move fluidly across it. What you'll do - Ship working tools, demos, and reference implementations on top of Harbor and open source AI tooling — fast. Days, not weeks. Code that makes architectural choices concrete enough for another developer to install, read, fork, and build on. - Make the layer architecture legible — reference implementations clean enough to read, documentation that maps the repo structure and clarifies the relationship between Web Agents API and Harbor SDK. If a developer or their coding assistant keeps reaching for the wrong primitive, that's yours to fix. - Be the technical practitioner in the room when it matters — a WICG call, a hackathon, a GitHub thread where a hard architecture question comes up. A community manager handles distribution and presence; your job is to show up with working code and real opinions when the conversation turns technical, and come back with a clear read on what developers are missing or getting wrong. -
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