Fullstack Engineer
Fullstack Engineers at AI companies build product features end-to-end across frontend, backend, and the integration layer between them. The day-to-day is recognizable full-stack work: designing API contracts, implementing UI alongside the services that power it, handling auth and data persistence, and owning features from product specification through production. Companies hire for this generalist profile in different contexts—at smaller companies, fullstack engineers often own most of a product surface; at larger companies, the role tends to bridge feature teams that would otherwise hand off across frontend/backend boundaries. AI-specific surfaces—integrating model APIs, building agent UIs, shipping LLM-backed features—are increasingly common but remain one type of feature work rather than the defining lens. These engineers typically sit within product engineering teams, collaborating with product, design, and ML or backend specialists as the architecture requires.
Measured across 233 of 233 open postings.
This role is advertised at 3 levels, so a single figure for the role would describe none of them. Experience and pay are the midpoints for each level on its own.
| Level | Share | Median years | Median pay |
|---|---|---|---|
| Mid | 49%(114) | 4 | $309k |
| Senior | 29%(67) | 5 | $229k |
| Staff / Principal | 18%(43) | 7 | $286k |
A dash means too few postings stated it to report a midpoint. Most companies do not publish a salary band, so pay is indicative rather than a market rate. 2 levels with fewer than 10 open postings are not shown.
“The Computer Use team teaches Claude to see and operate computer interfaces, and builds the agent harness and end-user products”
“Vannevar builds an agentic system that helps operators make sense of high-volume mission data”
“Build with AI as a primary tool, not a novelty. We expect you to use agents and coding models aggressively to move faster”
“Nice to have: experience building with AI agents, LLM APIs (OpenAI/Anthropic), or eval frameworks”
Requirements are a share of every open posting, so a role missing from this list is one where almost nobody asks. Work mode is different: many postings never say, so that figure counts only the ones that do. A posting stops being advertised when it is filled, cancelled or reorganised, so read the last figure as how long these stay on the market, not as time to hire.
Skills
What companies are looking for in this role.
Full-stack product engineering
Backend and API engineering
Frontend interface engineering
Distributed systems architecture
Product and interaction design
Systems performance optimization
Cloud infrastructure operations
Database and storage engineering
Data pipeline engineering
Monitoring and observability
Product analytics & experimentation
Developer platform engineering
Security engineering
Requirements & spec writing
LLM application development
AI-native product design
Agent workflow design
AI interface design
AI-assisted development workflow
Cross-functional collaboration
Mentoring and code review
Rapid prototyping and iteration
Technology
The tools and technologies that define this role.
Open Jobs
233 open Fullstack Engineer jobs across 82 companies.
Other Engineering roles
General-purpose software engineering roles focused on building and maintaining software systems. Covers generalist SWE positions that don't clearly fall into frontend, backend, fullstack, or other specialized tracks.
Engineers focused on server-side systems, APIs, services, and data processing pipelines. Includes roles explicitly labeled as backend or server-side development.
Engineers specializing in user-facing interfaces, web applications, and client-side development. Includes UI/UX engineering and web development roles.
Engineers building and maintaining internal platforms, cloud infrastructure, compute systems, and developer tooling.
Engineers embedded with customers or deployed on-site to solve domain-specific technical problems. Combines engineering skills with direct client interaction.