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Independent measurements of remote MCP servers. Every observation has a timestamp.

Read-only probes

MCP server · Automation & workflows

Buttondown MCP by usefulapi

Read Buttondown subscribers, emails, analytics and automations; add subscribers; write email drafts.

Checks passed
14 / 22

0 failed · 8 not measured

Median response
225 ms

Median of successful probes over 7 days

30-day uptime
Not measured

Share of countable probes over 30 days, including daily rollups. Auth challenges are excluded.

Discovered tools
25

Tool definitions returned by this server

Independent monitoring

Health & checks

Status history

Outdated check

Last connection measurement is over 24 hours old. Current availability is unknown.

Last checked
Check summary by test group
Test areaPassedFailedUnmeasured
ConnectionCan a client connect and discover tools?
500
Reliability & speedDoes it respond consistently and quickly?
004
Access & authenticationWhat is required to use this server?
102
Tool qualityAre the tool definitions usable by an agent?
400
Publisher identityCan the publisher be traced to its source?
402

Unmeasured means there is not enough evidence to decide. How these checks work

Inspect individual checks 22 recorded

Core

  • Pass
    Reachable

    Latest probe returned HTTP 200 in 225 ms.

  • Pass
    Valid handshake

    protocolVersion 2025-11-25, serverInfo.name buttondown-mcp.

  • Pass
    Lists tools

    tools/list returned 25 tools.

  • Pass
    Current protocol

    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}.

Discovered

Recent measurements

Probe history

View status
Latest stored probes. Raw probe rows are kept for 14 days.
CheckedResultResponseTools
Connected225 ms25