API keys generated from June 22, 2026 expire one year after creation; revoked keys cannot be reactivated. [1]
Guides · email · Popular APIs
Mailchimp Marketing API (API key or OAuth app)
Generate a Marketing API key (new keys expire after one year from 22 June 2026) for your own account, or register an OAuth app to act on other users' accounts.
Researched · not yet run liveLast researched 25 October 2026 · Mailchimp (Intuit) · provider site
Researched, not yet run live. Built from the provider’s official pages (linked below). A person hasn’t walked this flow end to end yet, so check each step against the source.
Who owns what
API keys belong to a Mailchimp user on an account; OAuth apps are registered under a Mailchimp account.
- Mailchimp account organisationThe user needs Manager permission or above to create API keys.
Steps
Steps marked “human step” are ones only you can do: verapli never signs in, submits, pays or accepts terms for you.
Create an API key
Profile > Extras > API keys > create a key with a descriptive name; copy it at once.
verapli captures
MAILCHIMP_API_KEYhere by plain code: encrypted in your browser, never shown to AI.If something goes wrong (1)
- A key created after June 22, 2026 stops working a year later: New keys expire 1 year after creation; generate a replacement before expiry. [1]
Where: https://us1.admin.mailchimp.com/
Note the server prefix
The data-centre prefix (e.g. us19) is in your admin URL and after the dash in the key; API base is https://{prefix}.api.mailchimp.com/3.0.
Register an OAuth app (acting on other accounts)optional
On the Registered Apps page click Register An App, fill in the form with your redirect URI, Create, then copy client ID and secret (secret shown once).
verapli captures
MAILCHIMP_CLIENT_SECREThere by plain code: encrypted in your browser, never shown to AI.Where: https://us1.admin.mailchimp.com/account/oauth2/
Terms and gotchas
Plain-English summary, not legal advice. Each card links its source.
What you end up with
| Env var | Secret | Format | What it is |
|---|---|---|---|
MAILCHIMP_API_KEY | secret | hex string ending in -us19 (server prefix) | Marketing API key |
MAILCHIMP_SERVER_PREFIX | not secret | us19 | Data-centre server prefix |
MAILCHIMP_CLIENT_ID | not secret | opaque id string | OAuth app client ID |
MAILCHIMP_CLIENT_SECRET | secret | opaque secret string | OAuth app client secret |
Renewals
- Mailchimp API key (keys created on or after 2026-06-22): every 1 year [1]
For agents
The same entry as JSON: /api/v1/entries/mailchimp/api · requirements /api/v1/requirements/mailchimp/api · terms /api/v1/terms/mailchimp/api.
Remote MCP (read-only, no auth)
claude mcp add --transport http verapli https://verapli.com/mcp
> "What do I need for Mailchimp Marketing API (API key or OAuth app), and how long will it take?"
→ tools/call requirements { "provider_id": "mailchimp/api" }Sources
- About API Keys Profile > Extras > API keys > create key with a descriptive name; full key visible only once; Manager permission needed (Admins can view others' keys); from June 22, 2026 new keys expire 1 year after creation; revoke is permanent. · accessed 25 October 2026 · official
- Access data on behalf of other users with OAuth 2 Registered Apps page (us1.admin.mailchimp.com/account/oauth2/) > Register An App; redirect URI (127.0.0.1 ok for dev); client_secret shown only once. · accessed 25 October 2026 · official
- Send your first API request Basic auth with any username and the API key; ping endpoint at api.mailchimp.com/3.0/ping. · accessed 25 October 2026 · official
- Marketing API Conventions Server prefix (data centre) e.g. us19 appears in the admin URL and as the API key suffix after the dash [to verify wording]. · accessed 25 October 2026 · official
Provider rules change. This page is generated from verapli registry version 2026.1025.316; spotted something out of date? Tell us. Mailchimp (Intuit) is not affiliated with verapli.