> AI agents: this is one page from PostHog's docs. Full index of Markdown docs for LLMs: https://posthog.com/llms.txt

# Linking Buttondown as a source

Canonical URL: https://posthog.com/docs/data-pipelines/sources/buttondown

> **Cloud region:** This page uses US Cloud hosts. For an EU Cloud project, use `https://eu.posthog.com` instead of `https://us.posthog.com` or `https://app.posthog.com` (app host for links).

## On this page

- [Prerequisites](#prerequisites)
- [Adding a data source](#adding-a-data-source)
- [Sync modes](#sync-modes)
- [Configuration](#configuration)
- [Supported tables](#supported-tables)
- [Troubleshooting](#troubleshooting)

![](https://res.cloudinary.com/dmukukwp6/image/upload/texture_tan_9608fcca70)

![](https://res.cloudinary.com/dmukukwp6/image/upload/texture_tan_dark_a92b0e022d)

Let AI connect your sources for you

Skip the manual setup — run this in your project and the wizard auto-detects your databases and APIs and connects them to PostHog.

`npx @posthog/wizard warehouse`

![PostHog Wizard hedgehog](https://res.cloudinary.com/dmukukwp6/image/upload/wizard_3f8bb7a240.png)

![](https://res.cloudinary.com/dmukukwp6/image/upload/wizard_3f8bb7a240.png)Let AI connect your sources for you

The Buttondown connector syncs automations, comments, emails, and more into the PostHog data warehouse, so you can analyze them alongside your product data.

## Prerequisites

Credentials that can read the data you want to sync. PostHog only reads data, so read access is enough.

## Adding a data source

1.  In PostHog, go to the [Sources tab](https://app.posthog.com/data-management/sources) of the data pipeline section.
2.  Click **\+ New source** and click **Link** next to this source.
3.  Enter your credentials (see [Configuration](#configuration) below) and click **Next**.
4.  Select the tables you want to sync, choose a sync method and frequency, then click **Import**.

Once the syncs are complete, you can start querying this data in PostHog.

Enter your Buttondown API key to sync your newsletter data.

You can find your API key on the [API page](https://buttondown.com/requests) in your Buttondown settings.

You'll be asked for:

-   **API key**

## Sync modes

Each table can be synced in one of several modes, depending on what the source supports:

-   **Webhook** (when available) – the source pushes changes to PostHog in real time. Fastest freshness, lowest ongoing cost, and the only mode that reliably captures updates and deletes.
-   **Incremental** – only new or updated rows are synced on each run, using a cursor field (such as an `updated_at` timestamp). Cheaper than a full refresh, but deletes aren't captured.
-   **Append only** – new rows are appended using a cursor field; existing rows are never updated. Ideal for immutable, append-only tables like event logs.
-   **Full refresh** – the whole table is reloaded on every sync. Use it when a table has no reliable cursor or when you need deletions reflected.

See [sync methods](https://posthog.com/docs/data-pipelines/sources.md#sync-methods) for a full explanation of how each mode works and how to choose between them.

All Buttondown tables are full refresh. Each sync replaces the contents of the table.

## Configuration

| Option | Type | Required |
| --- | --- | --- |
| `API key` | password | Yes |

## Supported tables

| Table | Description | Sync method | Incremental field | Primary key |
| --- | --- | --- | --- | --- |
| `automations` | An automation: a trigger, optional filters, and the actions Buttondown runs when a subscriber matches. | Full refresh | — | — |
| `comments` | A comment left on an email, by a subscriber or by the newsletter author. | Full refresh | — | — |
| `emails` | An email in the newsletter, covering drafts, scheduled sends, and sent issues, with its body and aggregate analytics. | Incremental, Full refresh | creation\_date | — |
| `events` | A per-subscriber email engagement event, such as a delivery, open, click, bounce, or unsubscribe. | Full refresh | — | — |
| `forms` | A registration form subscribers can sign up through, with its signup and page view counts. | Full refresh | — | — |
| `notes` | A note attached to a subscriber, email, or other object in the newsletter. | Full refresh | — | — |
| `prices` | A price for a paid subscription to the newsletter, backed by a Stripe product. | Full refresh | — | — |
| `subscribers` | A subscriber to the newsletter, with lifecycle state, signup attribution, and cached engagement counts. | Incremental, Full refresh | creation\_date | — |
| `survey_responses` | A single subscriber response to a survey. | Incremental, Full refresh | creation\_date | — |
| `surveys` | A survey subscribers can answer from an email, an automation, or a registration form. | Full refresh | — | — |
| `tags` | A tag that can be applied to subscribers for segmentation. | Full refresh | — | — |
| `automation_attempts` | An attempt to run an automation for one subscriber, with its scheduled time, status, and any error. | Full refresh | — | — |
| `referrals` | A subscriber who signed up through another subscriber's referral, with the full subscriber record of the referred subscriber. | Full refresh | — | — |
| `stripe_subscriptions` | A Stripe subscription that belongs to a subscriber, covering active and ended paid subscriptions. | Full refresh | — | — |

## Troubleshooting

-   If the connection fails with an authorization error, the API key is wrong, expired, or has been revoked. Create a new one, then reconnect the source.
-   If a table syncs no rows, the credential may not have access to that data. Check its permissions, then reconnect the source.

If your sync is failing or data looks wrong, see the [Data warehouse troubleshooting guide](https://posthog.com/docs/data-warehouse/troubleshooting.md). If that doesn't help, [contact support](https://us.posthog.com/#panel=support%3Asupport%3Adata_warehouse%3A%3Atrue) – we're happy to help.