Backend as a Service (BaaS)

Backend as a Service (BaaS) provides ready-made backend features like databases, auth, and storage so developers can focus on frontend code.

Backend as a Service (BaaS) is a cloud computing model that provides developers with pre-built backend functionality -- such as databases, user authentication, file storage, push notifications, and server-side logic -- through APIs and SDKs. Instead of building and operating backend infrastructure from scratch, developers integrate these managed services into their applications and focus primarily on the frontend and business logic.

What BaaS provides

A typical BaaS platform bundles several backend capabilities behind a unified API:

• Database and data storage: Managed databases (often real-time or document-oriented) that handle scaling, replication, and backups.

• User authentication: Sign-up, login, password reset, and identity federation flows with support for email/password, OAuth providers, and multi-factor authentication.

• File and object storage: APIs for uploading, storing, and serving files such as images, documents, and media.

• Push notifications: Sending notifications to mobile and web clients.

• Server-side functions: The ability to run custom backend logic in response to events, often through a built-in FaaS layer.

Popular BaaS platforms include Firebase (Google), Supabase (open source), AWS Amplify, and Appwrite. Each differs in its database model, pricing, self-hosting options, and extensibility.

BaaS vs. building your own backend

Building a custom backend gives full control but requires setting up servers, databases, authentication systems, deployment pipelines, and ongoing maintenance. BaaS trades some of that control for speed: a developer can go from zero to a working backend in hours rather than weeks.

The trade-off is flexibility. BaaS platforms impose their own data models, query languages, and scaling limits. Applications that outgrow the platform's constraints may need to migrate to a custom backend, which can be costly if the application is tightly coupled to the BaaS provider's proprietary APIs.

BaaS and API gateways

While BaaS platforms expose their own APIs, many applications combine BaaS with custom API services, third-party APIs, or multiple BaaS providers. An API gateway serves as the unified entry point that ties these pieces together, applying consistent authentication, CORS policies, and routing rules regardless of the backend.

Serverless API Gateway can route requests to BaaS endpoints alongside custom backend services. For example, you might configure the gateway to route authentication endpoints to Supabase, business logic endpoints to a custom service on AWS, and static asset requests to Cloudflare R2 -- all behind a single domain with consistent authorization policies managed at the gateway level.

Related documentation

• Authorizer Configuration - Configure JWT authentication across BaaS and custom backends

• Servers Configuration - Define BaaS platforms as upstream servers

• CORS Configuration - Set up cross-origin policies for frontend-to-BaaS communication