---
title: Importing contacts from CSV
description: Bulk-load contacts and their custom fields from a CSV file
icon: Upload
---

Plunk supports bulk-importing contacts from a CSV file — useful for migrating from another platform, loading an initial list, or syncing a large batch of contacts that you can't reasonably stream through `/v1/track`.

## CSV format

The CSV must have a header row. The only required column is `email`. Every other column becomes a custom field on the contact under `data.<columnName>`.

A minimal file:

```csv
email
ada@example.com
grace@example.com
linus@example.com
```

A richer file with custom fields:

```csv
email,firstName,plan,signupDate
ada@example.com,Ada,pro,2026-01-15T00:00:00Z
grace@example.com,Grace,enterprise,2025-11-02T00:00:00Z
linus@example.com,Linus,free,2026-04-21T00:00:00Z
```

In this example, every imported contact ends up with `data.firstName`, `data.plan`, and `data.signupDate` set.

### Rules and limits

- **File size**: up to 5 MB per upload. For larger lists, split the file and run multiple imports.
- **Encoding**: UTF-8. Non-UTF-8 files may produce garbled custom field values.
- **Email column**: must be present and valid. Rows with missing or invalid emails are reported back as errors.
- **Reserved column names**: `id`, `subscribed`, `createdAt`, `updatedAt`, and the auto-generated URL variables (`unsubscribeUrl`, etc.) are silently filtered out. Don't include them as columns.
- **Date columns**: use ISO 8601 (`2026-05-06T12:00:00Z`) so they're typed as dates and become usable with `within` / `olderThan` segment operators.
- **Boolean columns**: `true`, `false`, `yes`, `no` (case-insensitive) are stored as booleans and get the boolean toggle in segment filters.
- **Numeric columns**: plain integers and decimals (`42`, `3.14`) are stored as numbers and become usable with `gt` / `lt` segment operators. Leading-zero values (`01234`), `+`-prefixed numbers, and scientific notation stay strings so IDs, zip codes, and phone numbers aren't corrupted.
- **Existing contacts**: if a row's email matches an existing contact, the import **updates** the contact (merging the CSV's columns into `data`). It doesn't create a duplicate or overwrite the whole record.

## Importing your CSV

import {Tab, Tabs} from 'fumadocs-ui/components/tabs';

<Tabs items={['Dashboard', 'API']}>

<Tab value="Dashboard">

1. Open **Contacts** and click **Import**.
2. Pick your CSV file. Plunk validates the header and shows a preview of the first few rows.
3. Confirm. The import is queued and runs in the background.
4. The Imports page shows progress and any per-row errors when complete.

</Tab>

<Tab value="API">

For automation, use the import API:

**Step 1 — upload the CSV**

```bash
curl -X POST {{API_URL}}/contacts/import \
  -H "Authorization: Bearer sk_..." \
  -F "file=@contacts.csv"
```

The response includes a `jobId`:

```json
{ "jobId": "imp_abc123", "status": "queued" }
```

**Step 2 — poll for status**

```bash
curl {{API_URL}}/contacts/import/imp_abc123 \
  -H "Authorization: Bearer sk_..."
```

Poll every few seconds until `status` is `completed` or `failed`. The response includes counts:

```json
{
  "jobId": "imp_abc123",
  "status": "completed",
  "totalRows": 12000,
  "imported": 11985,
  "updated": 8,
  "skipped": 0,
  "errors": [
    { "row": 47,   "email": "bad@",      "reason": "invalid_email" },
    { "row": 1042, "email": "@example",  "reason": "invalid_email" }
  ]
}
```

`imported` counts new contacts created. `updated` counts existing contacts whose `data` was patched. `errors` lists per-row issues with row number and reason so you can fix and re-upload.

</Tab>

</Tabs>

## Tips

- **Unsubscribed contacts**: imported contacts are created subscribed by default. If your CSV represents users who never opted in, set up a workflow that filters out anyone you shouldn't email — or import them and then bulk-unsubscribe them with `POST /contacts/bulk-unsubscribe` to keep them on file but unmailed.
- **Custom fields appear in segments immediately**: as soon as the import finishes, you can build dynamic segments on any of the imported columns.
- **Idempotent reruns**: re-running the same CSV updates contacts in place rather than creating duplicates. If you fix a column and re-upload, all matching rows get the corrected value.

## Related

- [Custom fields](/guides/custom-fields) — how the `data.<column>` fields you import are typed and used.
- [Bulk operations](/api-reference/overview#contacts) — `bulk-subscribe`, `bulk-unsubscribe`, `bulk-delete` for mass actions on existing contacts (max 1,000 per call).
