Full stack refers to all the layers that make a web application work, stacked on top of each other: the interface in the browser, the server code behind it, the database underneath and the hosting it runs on. A full stack developer is someone who can build and fix every one of those layers, rather than specialising in one.
The layers of a typical stack
- Frontend. What runs in the browser: HTML, CSS, JavaScript, often with a framework like React. See frontend.
- API. The contract between browser and server, the requests one sends and the responses the other returns.
- Backend. Server code that applies business rules, handles logins and talks to other services. See backend.
- Database. Where data is stored, such as PostgreSQL or MySQL.
- Infrastructure. Hosting, domains, DNS, SSL and deployment pipelines.
A specific combination of tools is called a stack, and some have names. LAMP is Linux, Apache, MySQL and PHP, the classic WordPress setup. MERN is MongoDB, Express, React and Node.js. Many newer projects pair a React frontend with a hosted Postgres service like Supabase.
Example: one feature, every layer
A pet groomer wants customers to rebook their last appointment with one tap. Delivering it touches the whole stack: a button and confirmation screen on the frontend, a new API endpoint, backend logic to find the last booking and check the groomer's availability, a database query, and a deployment to release it. A full stack developer can build that alone; otherwise a frontend and a backend specialist split it and agree on the API between them.
Hiring full stack versus specialists
For most small businesses, one capable full stack developer is the practical choice: one person understands the whole system, and features do not stall waiting on a hand-off. The trade-off is depth. A generalist may be solid everywhere but not expert in, say, complex database performance or polished animation. Larger projects often keep a full stack lead and bring in specialists for specific problems.
Misunderstandings about full stack
- Assuming it covers design. Many full stack developers are not visual designers. Ask to see work, not just code.
- Assuming it includes operations. Running servers, backups and security monitoring is sometimes outside their remit; agree who owns it.
- Treating it as a guarantee of breadth. The title is self-assigned. Ask which stack they have actually shipped with.
- Choosing an exotic stack. A popular, well-documented stack makes it far easier to find the next developer.
Related terms
- Frontend: the top layer of the stack.
- Backend: the server layers beneath it.
- Web developer: the broader job title.
- API: the joint between frontend and backend.