Retrieve a newsletter's acquisition breakdown

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Allow AI tools and LLMs to interact with the API documentation portal through MCP.

MCP server URL

https://api-reference.usecommune.dev/mcp

Standard setup for AI tools providing an mcp.json file

mcp.json
{
  "REST API MCP server": {
    "url": "https://api-reference.usecommune.dev/mcp"
  }
}

Close
GET /newsletters/{newsletter}/growth

Where a newsletter's new subscribers came from over a window: the split by acquisition source, how many of them arrived through Commune itself, and how the invite funnel performed.

A subscriber's source is frozen when the row is first written, so migrating a newsletter between providers later never relabels the history.

The counts here are arrivals Commune recorded inside the window and are not the newsletter's audience size. For a newsletter connected to an outside provider they also miss anyone who joined at the provider between two imports.

invites describes Commune's own invitations to the people on the list who have no Commune account yet. Opting out of those is deliberately separate from unsubscribing from the newsletter, so opted_out here says nothing about whether those people still receive the email.

Headers

  • Commune-Version string(date)

    The contract version this request is written against, as a release date (YYYY-MM-DD). Omitting the header pins the request to the version that was current when the API key was issued, so an integration keeps working when a newer version ships. An unknown value answers 400 with invalid_version.

Path parameters

  • newsletter string Required

    The newsletter's id (a UUID) or its handle. A handle is unique across Commune and is the identifier its public web profile uses, so it is the one to hardcode in an integration.

Query parameters

  • expand string

    Comma separated list of relationship paths to inline in the response. Unexpanded relationships are returned as a reference object carrying only id and object. Each operation documents the paths it accepts, and an unknown path answers 400. Nested paths use a dot, for example article.newsletter.

    One accepted path is not a relationship. ?expand=content on GET /articles/{article} adds the Markdown rendition of the body beside the HTML one. It is the same trade the parameter always offers, a fuller response for a larger one, over a property that has more than one representation rather than over a reference.

  • fields string

    Comma separated allow list of top level properties to return on each object, so a client can trim a response it does not need in full. id and object are always returned. An unknown property name answers 400. Properties omitted by an operation, such as content on any article list, cannot be brought back with fields.

    A trimmed body is a subset of the schema this operation declares, and a property that schema marks required is absent when it was not asked for. That is the point of the parameter, so a client that validates responses against the schema either sends no fields or relaxes required.

  • period string

    A named window, counted back from today in UTC. Defaults to 30d. Ignored when since is given, so a request never has to reconcile two conflicting windows.

    Values are 7d, 14d, 30d, 90d, 6m, 1y, or all. Default value is 30d.

  • since string

    Start of the window, inclusive, as a date or an RFC 3339 timestamp. Giving this overrides period. A since later than until answers 400. Anything that is neither of those two shapes answers 400 as well, rather than being guessed at: a lenient parser would read 8/1/2026 as a date and give two callers different windows for the same string.

    Maximum length is 40.

  • until string

    End of the window, exclusive, as a date or an RFC 3339 timestamp. Defaults to now. Only meaningful alongside since.

    Maximum length is 40.

Responses

  • 200 application/json

    The acquisition breakdown for the resolved window.

    Hide response attributes Show response attributes object
    • object string Required

      Always newsletter_growth.

      Value is newsletter_growth.

    • newsletter object | null Required

      The newsletter that grew. A Ref unless newsletter is named in ?expand=.

      One of:
    • period_start string(date-time) Required

      Start of the resolved window, inclusive.

    • period_end string(date-time) Required

      End of the resolved window, exclusive.

    • by_source array[object] Required

      One entry per acquisition source that produced at least one subscriber inside the window, largest first. A source that produced none is omitted rather than returned as a zero.

      Hide by_source attributes Show by_source attributes object
      • source string | null Required

        How these people arrived. commune means they joined through Commune itself. Any other value names the provider or the file they came from. null for rows written before Commune recorded a source, which cannot be attributed after the fact.

      • known_subscribers integer Required

        How many subscriptions Commune recorded from this source inside the window. It counts arrivals Commune saw, so for a newsletter connected to an outside provider it misses anyone who joined at the provider between two imports.

        Minimum value is 0.

    • invites object Required

      Commune's invitations to the people on the list who do not have a Commune account yet, asking them to join the conversation around the newsletter they already read.

      This funnel is ring fenced from the subscription. Declining an invitation leaves the newsletter subscription untouched, so nothing here is an unsubscribe signal.

      Additional properties are NOT allowed.

      Hide invites attributes Show invites attributes object
      • sent integer Required

        Invitations Commune sent inside the window.

        Minimum value is 0.

      • accepted integer Required

        Invited people who created a Commune account inside the window. Attributed to the window they accepted in, not the one they were invited in, so the two numbers describe different cohorts and dividing one by the other is not a conversion rate.

        Minimum value is 0.

      • opted_out integer Required

        Invited people who asked for no further invitations inside the window. They still receive the newsletter.

        Minimum value is 0.

  • 400 application/json

    The request was malformed: an unknown query parameter, an unparseable cursor, an unknown expand path, or an unrecognised Commune-Version.

    Hide response attribute Show response attribute object
    • error object Required

      Additional properties are NOT allowed.

      Hide error attributes Show error attributes object
      • code string Required

        The stable, machine readable reason a request failed. New codes may be added in a minor version, so treat an unrecognised code as a generic failure of its HTTP status class.

        Values are bad_request, invalid_version, unauthorized, forbidden, insufficient_scope, payment_required, not_found, conflict, unprocessable, rate_limited, or internal_error.

      • message string Required

        A human readable sentence describing what went wrong. Written for a developer reading a log, not for an end user. Do not branch on it, branch on code.

      • param string

        The query, path or body parameter the error is attributed to, when the error is attributable to exactly one. Absent otherwise.

      • allowed_values array[string]

        Everything param would have accepted, when what it accepts is a finite set. Absent when it is not: a cursor, an identifier or a numeric range has nothing to enumerate, and an empty array would read as "nothing is allowed".

        It is deliberately redundant with message, which names the same values in prose. The array is what a program branches on and the sentence is what a model reads, and a caller correcting a request has to be able to do it from this one response without opening a reference page.

        On an unknown parameter name rather than an unknown value, this carries the parameter names the operation does accept, since that is the set the caller has to pick from.

        On an insufficient_scope failure there is no parameter at fault and param is absent, and this carries the scopes that would have been accepted instead.

      • request_id string

        Identifier for this request, echoed in the Commune-Request-Id response header. Quote it in support requests.

      • docs_url string(uri)

        Link to the reference page for this error code.

  • 401 application/json

    No API key was presented, or the key is unknown, revoked or expired.

    All four answer identically, down to the wording. Saying that a key was revoked rather than never issued confirms to whoever is holding the string that it was once real, which a legitimate caller does not need and a thief should not get.

    Hide headers attribute Show headers attribute
    • WWW-Authenticate string

      The authentication scheme this API accepts. Always Bearer realm="Commune API"; there is no second scheme and no query-parameter fallback, because a credential that can travel in a URL ends up in access logs and referer headers.

    Hide response attribute Show response attribute object
    • error object Required

      Additional properties are NOT allowed.

      Hide error attributes Show error attributes object
      • code string Required

        The stable, machine readable reason a request failed. New codes may be added in a minor version, so treat an unrecognised code as a generic failure of its HTTP status class.

        Values are bad_request, invalid_version, unauthorized, forbidden, insufficient_scope, payment_required, not_found, conflict, unprocessable, rate_limited, or internal_error.

      • message string Required

        A human readable sentence describing what went wrong. Written for a developer reading a log, not for an end user. Do not branch on it, branch on code.

      • param string

        The query, path or body parameter the error is attributed to, when the error is attributable to exactly one. Absent otherwise.

      • allowed_values array[string]

        Everything param would have accepted, when what it accepts is a finite set. Absent when it is not: a cursor, an identifier or a numeric range has nothing to enumerate, and an empty array would read as "nothing is allowed".

        It is deliberately redundant with message, which names the same values in prose. The array is what a program branches on and the sentence is what a model reads, and a caller correcting a request has to be able to do it from this one response without opening a reference page.

        On an unknown parameter name rather than an unknown value, this carries the parameter names the operation does accept, since that is the set the caller has to pick from.

        On an insufficient_scope failure there is no parameter at fault and param is absent, and this carries the scopes that would have been accepted instead.

      • request_id string

        Identifier for this request, echoed in the Commune-Request-Id response header. Quote it in support requests.

      • docs_url string(uri)

        Link to the reference page for this error code.

  • 403 application/json

    The key is valid but is not allowed to read this. Either it carries public scope and the operation needs creator scope, or it is bound to a different newsletter than the one addressed.

    Hide response attribute Show response attribute object
    • error object Required

      Additional properties are NOT allowed.

      Hide error attributes Show error attributes object
      • code string Required

        The stable, machine readable reason a request failed. New codes may be added in a minor version, so treat an unrecognised code as a generic failure of its HTTP status class.

        Values are bad_request, invalid_version, unauthorized, forbidden, insufficient_scope, payment_required, not_found, conflict, unprocessable, rate_limited, or internal_error.

      • message string Required

        A human readable sentence describing what went wrong. Written for a developer reading a log, not for an end user. Do not branch on it, branch on code.

      • param string

        The query, path or body parameter the error is attributed to, when the error is attributable to exactly one. Absent otherwise.

      • allowed_values array[string]

        Everything param would have accepted, when what it accepts is a finite set. Absent when it is not: a cursor, an identifier or a numeric range has nothing to enumerate, and an empty array would read as "nothing is allowed".

        It is deliberately redundant with message, which names the same values in prose. The array is what a program branches on and the sentence is what a model reads, and a caller correcting a request has to be able to do it from this one response without opening a reference page.

        On an unknown parameter name rather than an unknown value, this carries the parameter names the operation does accept, since that is the set the caller has to pick from.

        On an insufficient_scope failure there is no parameter at fault and param is absent, and this carries the scopes that would have been accepted instead.

      • request_id string

        Identifier for this request, echoed in the Commune-Request-Id response header. Quote it in support requests.

      • docs_url string(uri)

        Link to the reference page for this error code.

  • 404 application/json

    No such resource, or the key is not allowed to know that it exists. Commune answers 404 rather than 403 where distinguishing the two would leak the existence of private content.

    Hide response attribute Show response attribute object
    • error object Required

      Additional properties are NOT allowed.

      Hide error attributes Show error attributes object
      • code string Required

        The stable, machine readable reason a request failed. New codes may be added in a minor version, so treat an unrecognised code as a generic failure of its HTTP status class.

        Values are bad_request, invalid_version, unauthorized, forbidden, insufficient_scope, payment_required, not_found, conflict, unprocessable, rate_limited, or internal_error.

      • message string Required

        A human readable sentence describing what went wrong. Written for a developer reading a log, not for an end user. Do not branch on it, branch on code.

      • param string

        The query, path or body parameter the error is attributed to, when the error is attributable to exactly one. Absent otherwise.

      • allowed_values array[string]

        Everything param would have accepted, when what it accepts is a finite set. Absent when it is not: a cursor, an identifier or a numeric range has nothing to enumerate, and an empty array would read as "nothing is allowed".

        It is deliberately redundant with message, which names the same values in prose. The array is what a program branches on and the sentence is what a model reads, and a caller correcting a request has to be able to do it from this one response without opening a reference page.

        On an unknown parameter name rather than an unknown value, this carries the parameter names the operation does accept, since that is the set the caller has to pick from.

        On an insufficient_scope failure there is no parameter at fault and param is absent, and this carries the scopes that would have been accepted instead.

      • request_id string

        Identifier for this request, echoed in the Commune-Request-Id response header. Quote it in support requests.

      • docs_url string(uri)

        Link to the reference page for this error code.

  • 429 application/json

    Too many requests. Back off and retry after the interval named by the Retry-After response header.

    Hide headers attribute Show headers attribute
    • Retry-After integer

      Seconds to wait before retrying.

      Minimum value is 1.

    Hide response attribute Show response attribute object
    • error object Required

      Additional properties are NOT allowed.

      Hide error attributes Show error attributes object
      • code string Required

        The stable, machine readable reason a request failed. New codes may be added in a minor version, so treat an unrecognised code as a generic failure of its HTTP status class.

        Values are bad_request, invalid_version, unauthorized, forbidden, insufficient_scope, payment_required, not_found, conflict, unprocessable, rate_limited, or internal_error.

      • message string Required

        A human readable sentence describing what went wrong. Written for a developer reading a log, not for an end user. Do not branch on it, branch on code.

      • param string

        The query, path or body parameter the error is attributed to, when the error is attributable to exactly one. Absent otherwise.

      • allowed_values array[string]

        Everything param would have accepted, when what it accepts is a finite set. Absent when it is not: a cursor, an identifier or a numeric range has nothing to enumerate, and an empty array would read as "nothing is allowed".

        It is deliberately redundant with message, which names the same values in prose. The array is what a program branches on and the sentence is what a model reads, and a caller correcting a request has to be able to do it from this one response without opening a reference page.

        On an unknown parameter name rather than an unknown value, this carries the parameter names the operation does accept, since that is the set the caller has to pick from.

        On an insufficient_scope failure there is no parameter at fault and param is absent, and this carries the scopes that would have been accepted instead.

      • request_id string

        Identifier for this request, echoed in the Commune-Request-Id response header. Quote it in support requests.

      • docs_url string(uri)

        Link to the reference page for this error code.

  • 500 application/json

    Something failed inside Commune. The request may be retried.

    Hide response attribute Show response attribute object
    • error object Required

      Additional properties are NOT allowed.

      Hide error attributes Show error attributes object
      • code string Required

        The stable, machine readable reason a request failed. New codes may be added in a minor version, so treat an unrecognised code as a generic failure of its HTTP status class.

        Values are bad_request, invalid_version, unauthorized, forbidden, insufficient_scope, payment_required, not_found, conflict, unprocessable, rate_limited, or internal_error.

      • message string Required

        A human readable sentence describing what went wrong. Written for a developer reading a log, not for an end user. Do not branch on it, branch on code.

      • param string

        The query, path or body parameter the error is attributed to, when the error is attributable to exactly one. Absent otherwise.

      • allowed_values array[string]

        Everything param would have accepted, when what it accepts is a finite set. Absent when it is not: a cursor, an identifier or a numeric range has nothing to enumerate, and an empty array would read as "nothing is allowed".

        It is deliberately redundant with message, which names the same values in prose. The array is what a program branches on and the sentence is what a model reads, and a caller correcting a request has to be able to do it from this one response without opening a reference page.

        On an unknown parameter name rather than an unknown value, this carries the parameter names the operation does accept, since that is the set the caller has to pick from.

        On an insufficient_scope failure there is no parameter at fault and param is absent, and this carries the scopes that would have been accepted instead.

      • request_id string

        Identifier for this request, echoed in the Commune-Request-Id response header. Quote it in support requests.

      • docs_url string(uri)

        Link to the reference page for this error code.

GET /newsletters/{newsletter}/growth
curl "https://api.usecommune.com/newsletters/the-weekly/growth?period=90d" \
  -H "Authorization: Bearer $COMMUNE_API_KEY" \
  -H "Commune-Version: 2026-08-26"
curl \
 --request GET 'https://api.usecommune.com/newsletters/9a4c1c6e-0f2b-4f47-9d3f-6d1b1a2c3d4e/growth' \
 --header "Authorization: Bearer $ACCESS_TOKEN" \
 --header "Commune-Version: 2026-08-26"
Response examples (200)
{
  "object": "newsletter_growth",
  "newsletter": {
    "object": "newsletter",
    "id": "9a4c1c6e-0f2b-4f47-9d3f-6d1b1a2c3d4e"
  },
  "period_start": "2026-05-04T09:42:00Z",
  "period_end": "2026-05-04T09:42:00Z",
  "by_source": [
    {
      "source": "commune",
      "known_subscribers": 42
    }
  ],
  "invites": {
    "sent": 42,
    "accepted": 42,
    "opted_out": 42
  }
}
Response examples (400)
{
  "error": {
    "code": "bad_request",
    "message": "Newsletter not found.",
    "param": "cursor",
    "allowed_values": [
      "subscribed",
      "unsubscribed",
      "bounced",
      "complained",
      "pending"
    ],
    "request_id": "req_01j9c8h1q7m3n4p5r6s7t8u9v0",
    "docs_url": "https://usecommune.com/docs/api/errors#not_found"
  }
}
Response examples (401)
# Headers
WWW-Authenticate: string

# Payload
{
  "error": {
    "code": "bad_request",
    "message": "Newsletter not found.",
    "param": "cursor",
    "allowed_values": [
      "subscribed",
      "unsubscribed",
      "bounced",
      "complained",
      "pending"
    ],
    "request_id": "req_01j9c8h1q7m3n4p5r6s7t8u9v0",
    "docs_url": "https://usecommune.com/docs/api/errors#not_found"
  }
}
Response examples (403)
{
  "error": {
    "code": "bad_request",
    "message": "Newsletter not found.",
    "param": "cursor",
    "allowed_values": [
      "subscribed",
      "unsubscribed",
      "bounced",
      "complained",
      "pending"
    ],
    "request_id": "req_01j9c8h1q7m3n4p5r6s7t8u9v0",
    "docs_url": "https://usecommune.com/docs/api/errors#not_found"
  }
}
Response examples (404)
{
  "error": {
    "code": "bad_request",
    "message": "Newsletter not found.",
    "param": "cursor",
    "allowed_values": [
      "subscribed",
      "unsubscribed",
      "bounced",
      "complained",
      "pending"
    ],
    "request_id": "req_01j9c8h1q7m3n4p5r6s7t8u9v0",
    "docs_url": "https://usecommune.com/docs/api/errors#not_found"
  }
}
Response examples (429)
# Headers
Retry-After: 42

# Payload
{
  "error": {
    "code": "bad_request",
    "message": "Newsletter not found.",
    "param": "cursor",
    "allowed_values": [
      "subscribed",
      "unsubscribed",
      "bounced",
      "complained",
      "pending"
    ],
    "request_id": "req_01j9c8h1q7m3n4p5r6s7t8u9v0",
    "docs_url": "https://usecommune.com/docs/api/errors#not_found"
  }
}
Response examples (500)
{
  "error": {
    "code": "bad_request",
    "message": "Newsletter not found.",
    "param": "cursor",
    "allowed_values": [
      "subscribed",
      "unsubscribed",
      "bounced",
      "complained",
      "pending"
    ],
    "request_id": "req_01j9c8h1q7m3n4p5r6s7t8u9v0",
    "docs_url": "https://usecommune.com/docs/api/errors#not_found"
  }
}