Serverless is a cloud computing architecture in which developers deploy individual functions or application logic without provisioning, configuring, or maintaining the underlying server infrastructure. Despite the name, servers are still involved - they are simply abstracted away entirely by the cloud provider, leaving developers free to focus on writing code rather than managing machines.
In a traditional hosting model, a web application runs on one or more servers that must remain active at all times, regardless of whether they are receiving traffic. With serverless, also called Functions-as-a-Service (FaaS), code is broken into discrete units called functions. These functions are executed on demand, triggered by events such as an HTTP request, a database change, or a scheduled timer. The cloud provider handles all aspects of execution - allocating compute resources, scaling them up under load, and releasing them when the function completes.
This on-demand execution model has a direct impact on cost. In conventional cloud hosting, you pay for reserved capacity whether it is used or not. With serverless, billing is typically calculated per invocation and per millisecond of execution time, meaning an application with irregular or unpredictable traffic patterns can be significantly cheaper to operate.
Serverless also changes how teams think about scalability. Because the provider automatically spins up additional instances of a function in response to concurrent requests, there is no manual scaling configuration required. An application can handle a sudden spike in traffic just as easily as a quiet period, without any intervention from the development team.
The tradeoff is that serverless functions are stateless and short-lived by design. They are not suited to long-running processes or workloads that require persistent in-memory state between invocations. Developers must also account for cold starts - a brief latency penalty that occurs when a function is invoked after a period of inactivity and the provider needs to initialize a new execution environment.
Serverless is closely related to Edge Functions, which apply a similar execution model but run code at geographically distributed edge nodes rather than in a centralized data center, reducing latency for end users. Both approaches fit naturally into modern CI/CD pipelines, where individual functions can be deployed independently and rapidly without coordinating a full application release.
Popular serverless platforms include AWS Lambda, Google Cloud Functions, Cloudflare Workers, and Vercel Functions. The architecture is widely used for API backends, webhook handlers, image processing pipelines, and scheduled automation tasks - any workload where the ability to scale to zero and pay only for actual usage is an advantage.