Serverless web applications are a type of cloud computing architecture where the application backend infrastructure is fully managed by a cloud provider. In a serverless architecture, the application developers do not have to worry about managing servers, scaling infrastructure, or configuring load balancers.

Instead of provisioning and managing servers, the application is divided into smaller functions that are executed in response to specific events or HTTP requests. These functions are typically written in a serverless computing language like AWS Lambda, Azure Functions, or Google Cloud Functions.

Serverless web applications offer several advantages:

1. Easy scalability: The cloud provider automatically scales the infrastructure based on the demand. This allows the application to handle sudden traffic spikes without any manual intervention.

2. Cost-effective: Since serverless web applications only pay for the actual resource usage, it can be more cost-effective compared to traditional server-based applications. The cloud provider charges only for the execution time of the functions.

3. High availability: Serverless applications are designed to be highly available and fault-tolerant. The cloud provider takes care of replicating and distributing the functions across multiple data centers.

4. Faster development: Serverless architectures enable faster development cycles as developers can focus on writing code for individual functions rather than managing infrastructure. This allows for faster time-to-market and iterative development.

However, serverless architectures also have some limitations, such as potentially higher latency due to the cold start problem and limited control over the underlying infrastructure. Additionally, serverless architectures are not well-suited for long-running tasks or applications with specific resource requirements.

Overall, serverless web applications can be a powerful tool for building scalable and cost-effective web applications that can quickly adapt to changing demand.