# Build your own extension
URL: https://docs.awellhealth.com/docs/extensions/get-started

> For the complete documentation index, see [llms.txt](https://docs.awellhealth.com/llms.txt).



Building an extension lets a care flow drive actions in a system Awell doesn't already connect to.

## Proprietary apps and vendor tools [#proprietary-apps-and-vendor-tools]

**Proprietary apps.** Where a customer runs its own patient app, care team portal, or homegrown
electronic health record, a private extension lets non-engineer colleagues build care flows that drive
actions in those apps from the no-code builder. The connector is written once, then used by clinical
colleagues without coming back to engineering.

**Vendor tools.** Where care providers already use a vendor's tool, a public extension featured on the
[Marketplace](/docs/marketplace) means any Awell customer can build care flows that drive actions in it.

## Public or private [#public-or-private]

|            | Public                                    | Private                         |
| ---------- | ----------------------------------------- | ------------------------------- |
| Lives in   | Awell's `awell-extensions` repository     | The customer's own organization |
| Visible to | Every Awell customer, via the Marketplace | The organization that built it  |
| Built by   | Awell, or an outside contributor          | The customer's own team         |

A public extension goes in Awell's repository. Check it out locally to start contributing. See
[Contributing guidelines](/docs/extensions/contributing-guidelines).

## Prerequisites: Node, Yarn, TypeScript [#prerequisites-node-yarn-typescript]

Install Node and Yarn. Setup instructions for VS Code are in the repository.

Extensions are written in TypeScript, so this is engineering work, not configuration.

## Next steps [#next-steps]

**Next:** [Create an extension](/docs/extensions/create-an-extension).