# Source: https://www.activepieces.com/docs/handbook/engineering/onboarding/stack.md

> ## Documentation Index
> Fetch the complete documentation index at: https://www.activepieces.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Stack & Tools

## Language

Activepieces uses **Typescript** as its one and only language.
The reason behind unifying the language is the ability for it to break data models and features into packages, which can be shared across its components (worker / frontend / backend).

This enables it to focus on learning fewer tooling options and perfect them across all its packages.

## Frontend

* Web framework/library: [React](https://reactjs.org/)
* Layout/components: [shadcn](https://shadcn.com/) / Tailwind

## Backend

* Framework: [Fastify](https://www.fastify.io/)
* Database: [PostgreSQL](https://www.postgresql.org/)
* Task Queuing: [Redis](https://redis.io/)
* Task Worker: [BullMQ](https://github.com/taskforcesh/bullmq)

## Testing

* Unit & Integration Tests: [Jest](https://jestjs.io/)
* E2E Test: [Playwright](https://playwright.dev/)

## Additional Tools

* Application monitoring: [Sentry](https://sentry.io/welcome/)
* CI/CD: [GitHub Actions](https://github.com/features/actions) / [Depot](https://depot.dev/) / [Kamal](https://kamal-deploy.org/)
* Containerization: [Docker](https://www.docker.com/)
* Linter: [ESLint](https://eslint.org/)
* Logging: [OpenTelemetry](https://opentelemetry.io/)
* Building: [NX Monorepo](https://nx.dev/)

## Adding New Tool

Adding a new tool isn't a simple choice. A simple choice is one that's easy to do or undo, or one that only affects your work and not others'.

We avoid adding new stuff to increase the ease of setup, which increases adoption. Having more dependencies means more moving parts and support.

If you're thinking about a new tool, ask yourself these:

* Is this tool open source? How can we give it to customers who use their own servers?
* What does it fix, and why do we need it now?
* Can we use what we already have instead?

These questions only apply to required services for everyone. If this tool speeds up your own work, we don't need to think so hard.