Kit
Connect Kit to manage subscribers, tags, and forms, and build sequences, broadcasts, and segments for your audience.
You paste one Kit V4 API key, minted under Settings, Developer in the V4 Keys section.
- Setup time
- 2 min
- Auth
- API credentials
- API base URL
- https://api.kit.com/v4
- Rate limits
- API-key requests are capped at 120 per rolling 60 seconds. OAuth apps get 600 in the same window.
Before you begin
- A Kit account, formerly ConvertKit. V4 keys are not plan-restricted
- Access to the account's own settings. Keys are per-user, not per-team-member
Get your credentials
Open your Developer settings
Click Settings at the bottom left of the vertical nav and open Developer. You can also go straight to app.kit.com/account_settings/developer_settings.
Developer settings
Manage the keys and apps that connect to your Kit account.
| Name | API key | Created | Status |
|---|---|---|---|
| Reporting scriptCreated by you | ********************e195 | Jan 12, 2026 | Active |
- API Key
- Show
- API Secret
- Show
The V3 API Key and API Secret further down the page are the legacy credential and will not authenticate against v4.
Add a new V4 key
In the V4 Keys section click Add a new key and name it PopMCP. Click Create.
Developer settings
The name is for your own reference and is never sent to the API.
Copy the key before you close the dialog
Click Copy in the confirmation dialog and paste the value somewhere safe, then click Done.
Developer settings
Paste the key into PopMCP
Drop the value into API key and click connect.
Connect in PopMCP
Open your workspace, choose Kit in the marketplace, and fill in the connect dialog:
| Field | What to enter |
|---|---|
| API keysecret | In Kit go to Settings → Advanced → (or app.kit.com/account_settings/developer_settings) and create a V4 API key. Paste it here. It's sent as the X-Kit-Api-Key header and stored encrypted; used server-side only.Encrypted with AES-256-GCM on save and never shown again. |
PopMCP verifies the credential against Kit immediately. On success the connection flips to Verified and its MCP tools are provisioned.
Verify it worked
PopMCP marks Kit as Connected and the subscriber tools return your list. The first call it makes is GET https://api.kit.com/v4/account.
Troubleshooting
401 Unauthorized on every call
Why: A V3 API key or V3 API secret was pasted instead of a V4 key, or the V4 key was reset after you copied it.
Fix: Go back to Settings, Developer, look under V4 Keys rather than the V3 section, and add a new key.
You closed the dialog without copying the key
Why: Kit reveals the key once, at creation.
Fix: Edit the key and click Reset to issue a new value, then paste that into PopMCP. Resetting invalidates the old value immediately.
429 Too Many Requests
Why: API-key auth is capped at 120 requests per rolling 60 seconds.
Fix: Space out bulk runs, or build a Kit OAuth app if you need the 600 per 60 seconds ceiling.
403 on bulk or purchase endpoints
Why: Those routes require OAuth, not an API key.
Fix: Use the individual endpoints, or register a Kit app for OAuth access.
You cannot find Settings in the nav
Why: Kit's vertical navigation moved Settings and the account menu to the bottom left of the screen.
Fix: Look at the bottom left, or press the search field at the top of the nav and type Developer.