usefulapiButtondown MCP server
Read Buttondown subscribers, emails, analytics and automations; add subscribers; write email drafts. Hosted by usefulapi: connect it to Claude, ChatGPT, Cursor or any MCP client.
What can I ask?
Turn on the Buttondown connector, then ask in plain words. The AI picks the tools.
- How many subscribers do I have and who joined this week?
- How did my last newsletter perform on opens and clicks?
- Which drafts and scheduled emails do I have right now?
- Write a draft email called June Update with a short intro.
What you can do with Buttondown in Claude and ChatGPT
For newsletter authors who send email with Buttondown.
See how a newsletter email performed
The AI reads recipients, deliveries, opens, clicks, unsubscriptions and complaints for a sent email, and compares it with other emails.
Find and review subscribers
The AI lists or searches subscribers by email text, type, tag, signup date or domain, with open and click rates, and opens one subscriber.
Add a subscriber or change tags and notes
The AI adds one subscriber by email, or updates a subscriber's tags, private note or metadata.
Changes dataWrite or edit an email draft
The AI creates a draft email with subject and body, or edits a draft. Nothing is sent; you send it in Buttondown.
Changes dataReview automations and surveys
The AI lists automations and reads their performance, and lists surveys with their responses.
Compare tags by engagement
The AI lists subscriber tags and reads the number of new subscribers, the open rate and the click rate for a tag.
How do I connect Buttondown?
Before you connect
The login page asks for your Buttondown API key.
Find your key at buttondown.com/keys. A key with write access to subscribers, emails and tags makes every tool work; a read-only key works for the read tools. Your key is used only to call the Buttondown API on your behalf; it is never shown to anyone.
Claude claude.ai · Desktop
- Open Customize → Connectors, then click + Add → Add custom connector.
- Enter the name Buttondown and this URL, then click Add:https://
buttondown. usefulapi. io/ mcp - Claude opens the login page: enter your Buttondown API key.
- In a chat, click + → Connectors and turn on Buttondown.
Team and Enterprise: an Owner adds the connector for the organization first.
ChatGPT chatgpt.com
- Open Plugins, click +, then Add custom MCP server.
- Enter the name Buttondown and this URL, choose OAuth as the authentication, confirm the warning and create it:https://
buttondown. usefulapi. io/ mcp - ChatGPT opens the login page: enter your Buttondown API key.
- In Plugins, install Buttondown, then choose it in a chat.
No Add custom MCP server option? It depends on your account or workspace settings: see OpenAI's guide.
Claude Code
Run this command, then run /mcp in Claude Code to log in:
Cursor
Add to Cursor or add this to ~/.cursor/mcp.json:
{
"mcpServers": {
"buttondown": {
"url": "https://buttondown.usefulapi.io/mcp"
}
}
} VS Code
Add to VS Code or add this to .vscode/mcp.json:
{
"servers": {
"buttondown": {
"type": "http",
"url": "https://buttondown.usefulapi.io/mcp"
}
}
} Codex
Run these commands. The second one opens the login page:
Other clients
Windsurf, Cline, Zed and other MCP clients: add this URL as a remote MCP server (Streamable HTTP). The client then opens the login page in your browser.
Add only the URL. Do not add an Authorization header or an API key to the client config. The server signs you in with OAuth: the login page asks for your Buttondown API key. If the config has such a header, remove it: some clients then send that header instead of the login token, and every call fails with 401.
Pricing
| Plan | Price | Limit |
|---|---|---|
| Free | $0 | 50 tool calls / month |
| Proper user | $9/mo · $90/yr | 10,000 tool calls / month |
| Pro+per user | $39/mo · $390/yr | 100,000 tool calls / month |
Each paid plan covers this Buttondown server only. Ask your AI to run buttondown_upgrade and choose Pro or Pro+, billed monthly or yearly (it returns a Stripe Checkout link). If you already have Pro, ask to change it to Pro+. The change requires your confirmation, keeps your billing interval and charges the price difference for the rest of the period immediately. Cancel any time with buttondown_cancel_subscription: your paid plan continues to the end of the paid period, with no refund for the current period, and asking to resume the same plan with buttondown_upgrade before then undoes the cancel. Or write to support@usefulapi.io.
Tools 29
Show all 29 tools (the AI picks them for you)
Read only · 20
- Get account
buttondown_get_accountThe Buttondown account this API key belongs to: username and e-mail address. - List newsletters
buttondown_list_newslettersList the newsletters on the account with name, username, domains, sender, locale and timezone. The newsletter's API key, custom CSS and e-mail templates are never returned. - Get newsletter
buttondown_get_newsletterOne newsletter by id (settings and identity only; no API key, CSS or templates). - List subscribers
buttondown_list_subscribersList or search subscribers (newest first by default) with e-mail, type (regular, unactivated, unsubscribed, premium, ...), tags, notes, metadata, source, open/click rates and dates. Filter by e-mail text, type, tag, signup date or domain. - Get subscriber
buttondown_get_subscriberOne subscriber by id or by e-mail address: type, tags, notes, metadata, source, engagement and lifecycle dates. - List emails
buttondown_list_emailsList emails (drafts, scheduled and sent), newest first by default, with subject, status, publish date, slug, archive URL and analytics summary. The body is left out unless include_body is set. Filter by status, subject text or date. - Get email
buttondown_get_emailOne email by id with its full body, subject, status, publish date, slug, archive settings and analytics summary. - Get email analytics
buttondown_get_email_analyticsDelivery and engagement numbers for one sent email: recipients, deliveries, opens, clicks, failures, unsubscriptions, complaints, replies, page views. - List tags
buttondown_list_tagsList subscriber tags with name, color, descriptions and whether subscribers can edit them. - Get tag analytics
buttondown_get_tag_analyticsSubscribers created, open rate and click rate for one tag. - List automations
buttondown_list_automationsList automations (welcome sequences and other triggered e-mails) with name, status, trigger, actions and filters (webhook URLs in actions are shown by host only). Read-only: automations are not started or changed. - Get automation
buttondown_get_automationOne automation by id with its trigger, actions and filters. - Get automation analytics
buttondown_get_automation_analyticsPerformance numbers for one automation. - List surveys
buttondown_list_surveysList surveys with question, answers, status and response count. - List survey responses
buttondown_list_survey_responsesList survey responses (who answered what), optionally for one survey, email or subscriber. - List segments
buttondown_list_segmentsList saved subscriber segments with name, description and filters. - List forms
buttondown_list_formsList sign-up forms with title, slug, status, tags and subscriber counts. - List snippets
buttondown_list_snippetsList reusable content snippets with identifier, name, mode and how often each is referenced. - List webhooks
buttondown_list_webhooksList configured webhooks with status and subscribed event types. The signing key is never returned and the URL is shown by host only. - List email events
buttondown_list_eventsList delivery events (delivered, opened, clicked, bounced, unsubscribed, ...), newest first, optionally for one email or subscriber.
Changes data · 5
- Add a subscriber
buttondown_add_subscriberWRITE: add ONE subscriber by e-mail address. No subscriber type is set, so Buttondown applies the newsletter's normal sign-up rules (double opt-in: the subscriber is typically created as unactivated and Buttondown e-mails THAT ONE address a confirmation message; opt-in is never bypassed, nor is the firewall). Only add people who asked to subscribe. Creating a subscriber (and its tags) can also start the newsletter's own automations, which may e-mail that one subscriber. An existing e-mail is left untouched (error, no overwrite). Optional tags (a tag that does not exist is created, which needs a plan with tags), a private note and metadata. Buttondown limits creation to 100 subscribers per day. - Update a subscriber's tags, notes or metadata
buttondown_update_subscriberWRITE: change ONE subscriber's tags, private note or metadata. Tags are merged (add_tags / remove_tags change only those names; the others stay). A given note or metadata replaces the existing value (destructive for that field). The subscriber's type (unsubscribe, block, ...) and e-mail address cannot be changed here, and this tool sends nothing itself; but a tag, note or metadata change can start the newsletter's own automations (for example a tag-triggered welcome sequence), which may e-mail that one subscriber. - Create an email draft
buttondown_create_email_draftWRITE: create a DRAFT email (status always "draft"). Nothing is sent or scheduled and no subscriber is e-mailed; to send it, the user must open the draft in Buttondown and send it there. This server has no tool that sends or schedules email. Body is Markdown or HTML. - Edit an email draft
buttondown_update_email_draftWRITE: edit the subject, body, description, slug or preview image of an email that is still a DRAFT (replaces those fields; the previous text is lost unless Buttondown's email history is used). Refuses any email that is not a draft, and never changes status or publish date, so nothing is sent or scheduled. - Create a tag
buttondown_create_tagWRITE: create a subscriber tag (needs a Buttondown plan with tags). An existing tag with the same name is returned as an error and not changed.
Your usefulapi plan · 4
- Usage status (free-tier meter)
buttondown_usage_statusReport the caller's current usage: the plan, calls used this month, the limit of the plan (the free monthly cap or the Pro fair use limit), remaining, and whether the limit is reached. Read-only; does not count against the meter. - Request a missing feature
buttondown_request_featureTell usefulapi that the user needs something the Buttondown tools cannot do yet (a missing tool, field or filter). Call it only when the user asks for something none of the tools can do, and tell the user that you send the request. Do not call it for errors or for normal requests. Do not include personal data, credentials or customer records. Stored with the product name and the client type (for example Claude or Cursor), without the user's account. At most 5 requests per day. Does not count against the meter. - Upgrade to Pro or Pro+
buttondown_upgradeGet a paid plan for Buttondown (the free tier caps monthly usage). Pro: 10,000 tool calls a month, for normal use — plan "monthly" ($9/month) or "yearly" ($90/year, 2 months free). Pro+: 100,000 tool calls a month, for automations and heavy use — plan "plus" ($39/month) or "plus_yearly" ($390/year). Without a plan it returns both Pro and Pro+, each with a payment link, for the user to choose; with a plan, one link. An existing Pro subscription changes to Pro+ in place: call without confirm first, as the reply states the exact charge for this account (the price difference for the rest of the period, or in a free Pro trial the full Pro+ price, as the trial ends); then call with confirm: true. Cancel any time: the plan then runs to the end of the paid period, so it also suits a one-time job. A link opens Stripe Checkout in the browser; after payment the account upgrades automatically. Does not count against the meter. - Cancel the Pro subscription
buttondown_cancel_subscriptionCancel the caller's Buttondown Pro subscription at the end of the paid period (no refund for the current period; Pro continues until then, then the free tier applies). Requires confirm: true. Run buttondown_upgrade later to undo the cancel before the period ends. Does not count against the meter.
FAQ
What can I do with Buttondown in Claude or ChatGPT?
See how a newsletter email performed. Find and review subscribers. Add a subscriber or change tags and notes. Write or edit an email draft. Review automations and surveys. Compare tags by engagement. See what you can do for the details.
Is this an official Buttondown product?
No. usefulapi is an independent service. It is not affiliated with or endorsed by Buttondown. The server calls the Buttondown API with your own Buttondown access, so it sees only the data that your account can see.
Can I connect Buttondown to Claude or ChatGPT?
Yes. In Claude, add this server's URL as a custom connector. In ChatGPT, add it as a custom MCP server in Plugins. Then log in once. Cursor, VS Code, Claude Code and Codex work too. See the setup steps.
What do I need to connect?
The login page asks for your Buttondown API key. See Before you connect for where to find it.
Do I put my Buttondown key or an Authorization header in the client config?
No. Add only the URL. Do not add an Authorization header or an API key to the client config. The server signs you in with OAuth: the login page asks for your Buttondown API key. If the config has such a header, remove it: some clients then send that header instead of the login token, and every call fails with 401.
How do you keep my Buttondown credentials?
The login stores them encrypted in the authorization grant of your connection. The server uses them to call the Buttondown API for you and to derive a private account id for usage metering. usefulapi does not show them on any page or in any reply. To stop all access, remove the connector and change or delete these credentials in Buttondown.
Can the AI change my Buttondown data?
Yes, if you approve it. 5 of the 25 Buttondown tools can create or change data. The other 20 are marked read-only. Most MCP clients ask you to approve a tool call before it runs.
What does it cost?
The Free plan gives 50 tool calls / month. Pro costs $9/mo or $90/yr, with 10,000 tool calls / month. Pro+ costs $39/mo or $390/yr, with 100,000 tool calls / month. Each subscription covers this Buttondown server only. Cancel any time: your paid plan then runs to the end of the paid period. Run buttondown_usage_status to see how many calls you used.
How do I subscribe or cancel?
Ask the AI to run buttondown_upgrade and choose Pro or Pro+, billed monthly or yearly: it returns a Stripe Checkout link. If you already have Pro, ask to change it to Pro+. After you confirm, your existing subscription changes in place, keeps its billing interval and charges the price difference for the rest of the period immediately. To cancel, run buttondown_cancel_subscription. Your paid plan continues to the end of the paid period.
What if a Buttondown tool that I need is missing?
Tell the AI what you wanted to do. It can send the request with buttondown_request_feature. We store the text with the server name, the type of AI client and the tool you tried, not with your account, and read every request when we plan new tools. You can send up to 5 requests per day.
Which AI clients can I use?
Any client that supports remote MCP servers (Streamable HTTP) with OAuth login: Claude (web and desktop), Claude Code, ChatGPT, Codex, Cursor, VS Code, Windsurf and others.
This is a Model Context Protocol endpoint — meant to be connected from an AI client, not opened in a browser. An invalid_token response at the URL is the auth gate working as designed; clients authenticate automatically.
Need a tool this server does not have, or a connection to another system? We build custom integrations and MCP servers.