Klaviyo
Connect Klaviyo to manage profiles and segments, run email and SMS campaigns and flows, and track customer events.
You end up with one Klaviyo private API key (it starts with pk_) that you paste into PopMCP's "Private API key" field.
- Setup time
- 3 min
- Auth
- API credentials
- API base URL
- https://a.klaviyo.com/api
- Rate limits
- Klaviyo rate-limits per endpoint against a burst bucket and a steady bucket, commonly around 75 requests per second burst and 700 requests per minute steady. It returns 429 with a Retry-After header when you exceed either.
Before you begin
- A Klaviyo account on any plan, including free
- The Owner or Admin role. Klaviyo restricts creating, cloning and deleting private keys to those two roles
- A password manager or vault to paste the key into. Klaviyo never shows it again after creation
Get your credentials
Open the API keys page in Klaviyo settings
Click your account name in the bottom-left corner and choose Settings. Open API keys in the settings menu.
API keys
Public and private keys that authenticate requests to this Klaviyo account.
- Site ID
- ABC123
- Used by
- Klaviyo.js, forms, client-side tracking
| Name | Key | Access level | Created |
|---|---|---|---|
| Storefront syncCreated by Dana R. | pk_****9f31 | Full access | Mar 4, 2026 |
| Reporting exportCreated by Dana R. | pk_****71c8 | Read-only | Jan 12, 2026 |
Private keys are listed masked. Klaviyo never re-displays a full private key.
Create a private API key
Click Create Private API Key and give it a name you will recognise later, such as PopMCP. Select Full Access and click Create.
Create private API key
Scopes are fixed at creation. Changing them means deleting the key and making a new one.
Copy the key before you close the dialog
Click the copy icon next to the key and paste it straight into your password manager. Click Done to close the dialog.
API keys
This is the only time the full key is visible.
Paste the key into PopMCP
Open the Klaviyo connector in PopMCP, paste the key into Private API key, and save.
Connect in PopMCP
Open your workspace, choose Klaviyo in the marketplace, and fill in the connect dialog:
| Field | What to enter |
|---|---|
| Private API keysecret | Klaviyo → Settings → API keys → Create a private key. Stored encrypted; never displayed after saving.Encrypted with AES-256-GCM on save and never shown again. |
PopMCP verifies the credential against Klaviyo immediately. On success the connection flips to Verified and its MCP tools are provisioned.
Verify it worked
The Klaviyo connector in PopMCP flips to Connected and the tool list loads. Asking for your Klaviyo lists or metrics returns real names from your account.
Troubleshooting
401 Unauthorized on every call
Why: You pasted the public Site ID, a short six-character string, instead of a private key. Or the key was deleted in Klaviyo.
Fix: Private keys start with pk_ and are long. Create a fresh private key on the API keys page and paste that.
403 Forbidden on some tools only
Why: The key was created with Read-only or Custom Access and is missing the scope that tool needs.
Fix: Klaviyo cannot edit scopes after creation. Delete the key and create a new one with Full Access, or with the specific scopes added.
You closed the dialog without copying the key
Why: Klaviyo displays a private key exactly once.
Fix: Delete that key from the API keys page and create a replacement, or use the three-dot menu and Clone to mint a new key with the same name and scopes.
The API keys page is not visible, or Create Private API Key is greyed out
Why: Only Owner and Admin users can create, clone or delete a private API key.
Fix: Ask an Owner or Admin to create the key, or to raise your role under Settings, Users.
The key works but nothing rotates it
Why: Klaviyo does not expire private keys or email replacements on a schedule.
Fix: Rotate on your own cadence. Clone the key, paste the new value into PopMCP, then delete the old key.