PaaS, or Platform as a Service, is cloud hosting where you hand over your application's code and the provider takes care of servers, operating systems, language runtimes and scaling. You decide what the app does; the platform decides how it stays running.
From git push to a running app
A developer connects a code repository or uploads a build. The platform detects the language (Node.js, Python, Ruby and so on), installs dependencies, builds the app and starts it in one or more managed containers. It assigns a URL, terminates HTTPS, restarts crashed processes and lets you add more instances with a slider or setting. Databases, caches and queues are usually available as add-ons with a click, configured through environment variables.
Compared with IaaS, you lose low-level control (no choosing kernel versions or installing arbitrary system packages) in exchange for never patching an operating system. Compared with serverless, your app is a long-running process rather than functions that start per request.
Well-known PaaS products
Heroku popularised the model in the late 2000s. Render, Railway, Fly.io, Google App Engine, AWS Elastic Beanstalk and Azure App Service are common today, and front-end platforms like Vercel and Netlify blend PaaS with serverless functions. Example: a dog-grooming business commissions a small booking app with a customer login. The developer deploys it to Render with a managed Postgres database; each merge to the main branch triggers an automatic deployment.
Where PaaS fits for a small business
PaaS is the sensible home for a custom web app that needs a server process and a database, when you do not have anyone to run infrastructure. If you only need a brochure site or a shop, a website builder or SaaS store is less work again. Costs on PaaS are predictable at small scale but can climb faster than raw servers as traffic grows, which is when some teams move to IaaS.
PaaS mistakes to avoid
- Relying on the local filesystem. Containers are replaced on every deploy, so uploaded files vanish unless stored in object storage.
- Free tiers that sleep. Some free plans spin an idle app down, so the first visitor waits many seconds.
- Committing secrets. API keys belong in the platform's environment settings, not in the repository.
- No database backups plan. Check what the add-on keeps and for how long before you need it.
Related terms
- IaaS: one layer down, with full control and full responsibility.
- SaaS: one layer up, finished software.
- CI/CD: the pipeline that usually feeds a PaaS.
- Serverless: per-request functions instead of a running app.