Linking Plunk as a source
This source is currently in alpha. The interface and available tables may change.
Sync your Plunk contacts, campaigns, templates, and segments into the PostHog data warehouse, so you can join email engagement with product analytics, for example to compare campaign performance against activation or retention.
Prerequisites
You need the secret API key for your Plunk project. It starts with sk_ and is shown in your Plunk project settings. The public key (pk_) only works for event tracking and cannot read data.
Adding a data source
- In PostHog, go to the Sources tab of the data pipeline section.
- Click + New source and click Link next to this source.
- Enter your credentials (see Configuration below) and click Next.
- 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.
- In Plunk, open Project Settings and go to the API Keys section, then copy the secret key (
sk_...). - Back in PostHog, enter the secret API key.
- If you self-host Plunk, set the API URL to your Plunk API host (for example
https://plunk-api.example.com). Leave it blank to use the hosted Plunk athttps://next-api.useplunk.com. - Click Next, select the tables you want to sync, set the sync method and frequency, then click Import.
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_attimestamp). 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 for a full explanation of how each mode works and how to choose between them.
Plunk's API exposes no server-side timestamp filter on its list endpoints, so every table is full refresh only and reloads all records on each sync.
Configuration
| Option | Type | Required |
|---|---|---|
Secret API key | password | Yes |
API URL (self-hosted only) | text | No |
Supported tables
| Table | Description | Sync method | Incremental field | Primary key |
|---|---|---|---|---|
contacts | A person who can receive emails from the project, with their subscription state and custom metadata. | Full refresh | — | — |
campaigns | A one-time email broadcast sent to all contacts, a segment, or a filtered audience, with its delivery and engagement counts. | Full refresh | — | — |
templates | A reusable email template with subject, HTML body, and sender details, referenced by campaigns and workflow steps. | Full refresh | — | — |
segments | A saved audience of contacts, either dynamic (filter-based) or static (manually managed), with its cached member count. | Full refresh | — | — |
Troubleshooting
If a sync fails with an authentication error, check that you are using the secret key (sk_), not the public key (pk_), and that the key was not regenerated in Plunk. Copy the current secret key from your Plunk project settings and reconnect the source.
If Plunk rejects requests with a permission error, check that your Plunk project is active and that your account email is verified.
If your sync is failing or data looks wrong, see the Data warehouse troubleshooting guide. If that doesn't help, contact support – we're happy to help.