Negotiated 2025-11-25. The bar is 2025-06-18 or newer.
Pass
HTTPS
The endpoint URL is https.
Performance
Not measured
Fast (p50)
Median latency 225 ms over 1 samples in 7 days. The bar is 1000 ms. Need at least 5 samples.
Not measured
Consistent (p95)
95th percentile 225 ms over 1 samples in 7 days. The bar is 3000 ms. Need at least 20 samples.
Not measured
Reliable (uptime)
1 of 1 attempts returned a tool list in 30 days (100%). The bar is 99%. Need at least 30 samples.
Not measured
Stable tool list
Fewer than two successful probes in 30 days, so tool-list stability is not measured.
Access
Pass
Open access
tools/list succeeded with no credential, and the record declares none.
Not measured
Standard auth
Auth is not required, so the OAuth metadata check does not apply.
Not measured
Free tier cited
No publisher quote has been checked.
Tools
Pass
Tools described
Every tool description is at least 20 characters.
Pass
Valid input schemas
Every inputSchema is a JSON Schema object.
Pass
Parameters documented
68 of 76 parameters have a description (89%). The bar is 80%.
Pass
Safety hints
Every tool sets readOnlyHint or destructiveHint.
Publisher
Pass
Verified namespace
Listed in the Official MCP Registry.
Pass
Website matches publisher
The website host matches the reverse-domain namespace.
Pass
Source repo linked
A repository URL is on file.
Not measured
Repo owner matches
This namespace is not an io.github login, so the owner comparison does not apply.
Pass
Recently updated
Updated 2026-11-10T23:33:57.787743Z, within 180 days.
Not measured
Open-source licence
The GitHub licence lookup has not returned an OSI result yet.
Start using Buttondown MCP by usefulapi
Connect to this server
Choose your client, copy the configuration, then enable the server in your client’s MCP settings.
Run this command in your terminal, then restart Claude Code.
Claude Code
claude mcp add --transport http buttondown-mcp-by-usefulapi https://buttondown.usefulapi.io/mcp
Capabilities
Tools 25
buttondown_add_subscriber
WRITE: 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. POST /subscribers.
Discovered buttondown_create_email_draft
WRITE: 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. POST /emails.
Discovered buttondown_create_tag
WRITE: 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. POST /tags.
Discovered buttondown_get_account
The Buttondown account this API key belongs to: username and e-mail address. GET /accounts/me.
Discovered buttondown_get_automation
One automation by id with its trigger, actions and filters. GET /automations/{id}.
Discovered buttondown_get_automation_analytics
Performance numbers for one automation. GET /automations/{id}/analytics.
Discovered buttondown_get_email
One email by id with its full body, subject, status, publish date, slug, archive settings and analytics summary. GET /emails/{id}.
Discovered buttondown_get_email_analytics
Delivery and engagement numbers for one sent email: recipients, deliveries, opens, clicks, failures, unsubscriptions, complaints, replies, page views. GET /emails/{id}/analytics.
Discovered buttondown_get_newsletter
One newsletter by id (settings and identity only; no API key, CSS or templates). GET /newsletters/{id}.
Discovered buttondown_get_subscriber
One subscriber by id or by e-mail address: type, tags, notes, metadata, source, engagement and lifecycle dates. GET /subscribers/{id_or_email}.
Discovered buttondown_get_tag_analytics
Subscribers created, open rate and click rate for one tag. GET /tags/{id}/analytics.
Discovered buttondown_list_automations
List 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 /automations.
Discovered buttondown_list_emails
List 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 /emails.
Discovered buttondown_list_events
List delivery events (delivered, opened, clicked, bounced, unsubscribed, ...), newest first, optionally for one email or subscriber. GET /events.
Discovered buttondown_list_forms
List sign-up forms with title, slug, status, tags and subscriber counts. GET /forms.
Discovered buttondown_list_newsletters
List 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 /newsletters.
Discovered buttondown_list_segments
List saved subscriber segments with name, description and filters. GET /segments.
Discovered buttondown_list_snippets
List reusable content snippets with identifier, name, mode and how often each is referenced. GET /snippets.
Discovered buttondown_list_subscribers
List 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 /subscribers.
Discovered buttondown_list_survey_responses
List survey responses (who answered what), optionally for one survey, email or subscriber. GET /survey_responses.
Discovered buttondown_list_surveys
List surveys with question, answers, status and response count. GET /surveys.
Discovered buttondown_list_tags
List subscriber tags with name, color, descriptions and whether subscribers can edit them. GET /tags.
Discovered buttondown_list_webhooks
List configured webhooks with status and subscribed event types. The signing key is never returned and the URL is shown by host only. GET /webhooks.
Discovered buttondown_update_email_draft
WRITE: 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. PATCH /emails/{id}.
Discovered buttondown_update_subscriber
WRITE: 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. PATCH /subscribers/{id_or_email}.