Backends on Vercel

Backends deployed to Vercel receive the benefits of Vercel's infrastructure, including: -   [Fluid compute](https://vercel.com/docs/fluid-compute): Zero-configuration, optimized concurrency, dynamic scaling, background processing, automatic cold-start prevention, region failover, and more-   [Active CPU pricing](https://vercel.com/docs/functions/usage-and-pricing): Only pay for the CPU you use, not waiting for I/O (e.g. calling AI models, database queries)-   [Instant Rollback](https://vercel.com/docs/instant-rollback): Quickly revert to a previous production deployment-   [Vercel Firewall](https://vercel.com/docs/vercel-firewall): A robust, multi-layered security system designed to protect your applications-   [Preview deployments with Deployment Protection](https://vercel.com/docs/deployments/environments#preview-environment-pre-production): Secure your preview environments and test changes safely before production-   [Rolling releases](https://vercel.com/docs/rolling-releases): Gradually roll out backends to detect errors early Deploy the following backends to Vercel with zero-configuration. ![Elysia](https://api-frameworks.vercel.sh/framework-logos/elysia.svg) ### Elysia Ergonomic framework for humans ![Express](https://api-frameworks.vercel.sh/framework-logos/express.svg)![Express](https://api-frameworks.vercel.sh/framework-logos/express-dark.svg) ### Express Fast, unopinionated, minimalist web framework for Node.js ![FastAPI](https://api-frameworks.vercel.sh/framework-logos/fastapi.svg) ### FastAPI FastAPI framework, high performance, easy to learn, fast to code, ready for production ![Fastify](https://api-frameworks.vercel.sh/framework-logos/fastify.svg)![Fastify](https://api-frameworks.vercel.sh/framework-logos/fastify.svg) ### Fastify Fast and low overhead web framework, for Node.js ![Flask](https://api-frameworks.vercel.sh/framework-logos/flask.svg) ### Flask The Python micro web framework ![H3](https://api-frameworks.vercel.sh/framework-logos/h3.svg) ### H3 Universal, Tiny, and Fast Servers ![Hono](https://api-frameworks.vercel.sh/framework-logos/hono.svg) ### Hono Web framework built on Web Standards ![Koa](https://api-frameworks.vercel.sh/framework-logos/koa.svg) ### Koa Expressive middleware for Node.js using ES2017 async functions ![NestJS](https://api-frameworks.vercel.sh/framework-logos/nestjs.svg) ### NestJS Framework for building efficient, scalable Node.js server-side applications ![Nitro](https://api-frameworks.vercel.sh/framework-logos/nitro.svg) ### Nitro Nitro is a next generation server toolkit. ![xmcp](https://api-frameworks.vercel.sh/framework-logos/xmcp.svg) ### xmcp The MCP framework for building AI-powered tools To process background tasks with Python, you can deploy [Celery](https://vercel.com/docs/frameworks/backend/celery) or [Dramatiq](https://vercel.com/docs/frameworks/backend/dramatiq) workers as queue-triggered Vercel Functions. If you are transitioning from a fully managed server or containerized environment to Vercel’s serverless architecture, you may need to rethink a few concepts in your application since there is no longer a server always running in the background. The following are generally applicable to serverless, and therefore Vercel Functions (running with or without Fluid compute). Vercel Functions can serve WebSocket connections when [Fluid compute](https://vercel.com/docs/fluid-compute) is enabled. WebSocket connections follow [Vercel Function limits](https://vercel.com/docs/functions/limitations), including maximum duration, so clients should handle reconnects when a connection closes. Store persistent state, rooms, presence, and pub/sub coordination in an external data store instead of relying on in-memory state. Learn more in the [WebSockets documentation](https://vercel.com/docs/functions/websockets). To manage database connections efficiently, [use the `attachDatabasePool` function from `@vercel/functions`](https://vercel.com/docs/functions/functions-api-reference/vercel-functions-package#database-connection-pool-management).