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

# Linking Courier as a source

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

> **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 Courier connector syncs your notification data – messages, audit events, audiences, brands, tenants, automations, notification template versions, and user preference data – into PostHog, so you can analyze notification delivery and engagement alongside your product data.

## Prerequisites

You need a [Courier](https://www.courier.com/) account with access to an API key. Find your API key in the Courier dashboard under **Settings** > **API Keys**. Either the Live or Test key works – the key determines which environment's data is synced.

## 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.

You need your Courier API key. Find it in the Courier dashboard under **Settings** > **API Keys**.

## 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.

The `Messages` table supports incremental sync on `enqueued` using Courier's server-side `enqueued_after` filter, so ongoing syncs only fetch new messages. Engagement fields that change on existing messages after delivery (like `clicked`, `opened`, and `delivered`) are only refreshed by a full refresh, so consider scheduling periodic full refreshes of `Messages` if you rely on those fields.

The `PreferenceChanges` table supports incremental sync on `timestamp` using Courier's `since` filter, so ongoing syncs only fetch new preference changes.

The `Automations`, `AuditEvents`, `Audiences`, `Brands`, `NotificationTemplateVersions`, `PreferenceSections`, `PreferenceTopics`, and `Tenants` tables don't have server-side timestamp filters in Courier's API, so they always sync as a full refresh.

## Configuration

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

## Supported tables

| Table | Description | Sync method | Incremental field | Primary key |
| --- | --- | --- | --- | --- |
| `Messages` | A message you've sent through Courier, with its current delivery status and engagement timestamps. | Incremental, Full refresh | enqueued | — |
| `MessageHistory` | One entry per status transition of a sent message, giving the delivery funnel behind the message's current status. | Incremental, Full refresh | enqueued | — |
| `AuditEvents` | An account-level activity log entry recording an action taken by a user or API key in your Courier workspace. | Full refresh | — | — |
| `Audiences` | A saved, filter-defined segment of recipients used to target notifications. | Full refresh | — | — |
| `AudienceMembers` | A user currently matching an audience's filter. Courier recalculates membership as user profiles change. | Full refresh | — | — |
| `Brands` | A branding profile (colors, logo, templates) that can be applied to messages sent through Courier. | Full refresh | — | — |
| `Lists` | A named group of recipients that a send can target as a whole, instead of one user at a time. | Full refresh | — | — |
| `ListSubscriptions` | A user's subscription to a list, with the notification preferences recorded for that subscription. | Full refresh | — | — |
| `NotificationTemplates` | A notification template in the workspace, resolving the template id every sent message carries. | Full refresh | — | — |
| `NotificationTemplateVersions` | A version of a notification template, most recent first, for comparing performance across publishes. | Full refresh | — | — |
| `Automations` | A saved automation template in the workspace, the legacy workflow product that Journeys supersede. | Full refresh | — | — |
| `PreferenceSections` | A preference section in the workspace, grouping the subscription topics shown on the preference page. | Full refresh | — | — |
| `PreferenceTopics` | A subscription topic in the workspace, the topic that user preferences and preference changes refer to. | Full refresh | — | — |
| `PreferenceChanges` | One change a user made to one subscription topic, with the value before it. The latest change per user and topic gives that user's current subscription state. | Incremental, Full refresh | timestamp | — |
| `Tenants` | A tenant used to scope notification sending and preferences for a group of recipients (e.g. a customer account). | Full refresh | — | — |
| `TenantUsers` | A user's membership of a tenant, which is who a tenant-scoped send reaches. | Full refresh | — | — |
| `Journeys` | A journey in the workspace: the multi-step flow a message can be attributed to. Lists the published version of each journey. | Full refresh | — | — |
| `JourneyVersions` | A published version of a journey, most recent first, giving the publish history behind a journey's current behaviour. | Full refresh | — | — |
| `DigestInstances` | What a digest schedule has accumulated for one user, explaining why their messages were batched or held back. | Full refresh | — | — |

## Troubleshooting

If the source fails to connect or a sync stops with an authorization error, your API key is likely invalid or revoked – generate a new key in the Courier dashboard under **Settings** > **API Keys** and update the source credentials. If a table is unexpectedly empty, check that you connected the key for the right Courier environment, since each key only sees its own environment's data.

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.