Functions-as-a-service (FaaS) allows you to write small, discrete units of code with event-based execution. Developers deploy code without worrying about the infrastructure it will run on.
Leveraging Knative and Kubernetes, users will be able to define and manage functions in GitLab. This includes security, logging, scaling, costs, of their serverless implementation for a particular project/group.
Code executes when it's needed so you don't use compute resources while your app is idle. GitLab Serverless allows you to run your own FaaS on any infrastructure without the vendor lock-in of traditional cloud function services.
- Documentation - docs.gitlab.com 
Serverless computing provides an easy way to build highly scalable applications and services, eliminating the pains of provisioning & maintaining.
Today it's mostly used one-off for e.g. image transformations and ETL, but given the potential and the rise of microservices, it's fully possible to build complex, complete applications on nothing but serverless functions and connected services.
# Competitive landscape - AWS Lambda - Azure Functions - Google Cloud Function - Serverless Framework
# Analyst landscape
The Serverless category is currently coupled with IaaS reports. - Gartner's Magic Quadrant for Cloud Infrastructure as a Service places AWS, Azure, and Google Cloud as leaders. - Forrester places Serverless Computing in their Emerging Technology Spotlight category, with the big three as leaders (AWS, Azure, Google Cloud)
# See also - GraalVM - Kubeless - GitLab Serverless and Knative - Polyglot Webservice Hosting