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

# Source builder

> Have an agent build an API connector for any source system, so Vern can pull a customer's data itself instead of waiting on exports.

When a source system has an API but no connector in Vern's library, a **source
builder** makes one. Point it at the API's docs and an agent works out how to
sign in, which objects to pull and how to page through them — then you add the
finished connector to your [sources](https://docs.vern.so/help-center/sources/sources.md).

Building a source is **Admin-only**. You can also ask
[Home](https://docs.vern.so/help-center/home/overview.md) to build one for you.

## Build one

**1. Start**

Go to **Sources**, click **Source builders**, then **Build a source**.
Under **Search for the API**, enter a docs or OpenAPI URL, or just an API
name (e.g. *Chargebee*).

**2. Let the agent build it**

The agent reads the API, picks the endpoints, and writes the connector. It
may stop to ask you to choose between options — answer and it continues.
Request a change at any time, for example *"Add the invoices stream"* or
*"Only pull active customers"*, and **Stop** it if it's heading the wrong
way.

**3. Verify (optional)**

Click **Verify connector** and enter a real account's credentials. The agent
dry-runs every stream until each one passes, then publishes the verified
version. You can skip this — the connector is published **Unverified** and
you enter credentials when you start a migration.

**4. Add to sources**

Click **Add to sources**. The source now appears with an **API** badge, and
imports for companies on it can use **Extract via** *source name*.

APIs that only support interactive OAuth sign-in aren't supported yet; the
agent tells you if it finds one.

Credentials are never typed into the chat. They're entered on the build's own
page and stored write-only.

## Next

* [Sources](https://docs.vern.so/help-center/sources/sources.md) — where the finished connector lives.
* [Write to an API](https://docs.vern.so/help-center/send/write-to-an-api.md) — the same idea, for writing data into your app.


This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.