millionsend

Official Python SDK for MillionSend — a self-hostable, Resend-compatible email API on AWS SES.

The API is wire-compatible with Resend and this SDK deliberately mirrors the shape of the resend PyPI package, so migrating is mostly a find-and-replace: swap the import, set base_url to your instance.

Install

pip install millionsend

Requires Python 3.9+. Depends only on requests.

Quickstart

import millionsend

millionsend.api_key = "ms_123"
millionsend.base_url = "https://mail.acme.dev"  # your instance

email = millionsend.Emails.send({
    "from": "Acme <onboarding@acme.dev>",
    "to": "delivered@resend.dev",
    "subject": "Hello from MillionSend",
    "html": "<strong>It works!</strong>",
})

print(email.id)  # responses support both email["id"] and email.id

Configuration

Config is module-level (no client object to construct):

import millionsend

millionsend.api_key  = "ms_123"                  # or env MILLIONSEND_API_KEY
millionsend.base_url = "https://mail.acme.dev"   # or env MILLIONSEND_BASE_URL
millionsend.timeout  = 30                        # optional, seconds (default 60)

• api_key falls back to MILLIONSEND_API_KEY. Missing key raises MissingApiKeyError on the first call.
• base_url falls back to MILLIONSEND_BASE_URL, then http://localhost:3001. MillionSend is self-hosted, so set this to your deployment in production.

Request/response casing: request params are plain dicts in the API's snake_case (reply_to, scheduled_at, first_name). Responses are dict subclasses that also allow attribute access (resp.id, resp.data[0].id).

Errors

Every call raises on a non-2xx response. The base is MillionSendError; known error names map to subclasses so you can catch them:

from millionsend import NotFoundError, MillionSendError

try:
    contact = millionsend.Contacts.get(email="ghost@acme.dev")
except NotFoundError:
    ...  # 404
except MillionSendError as e:
    print(e.code, e.status_code, e.message)

• e.code is the stable name discriminant (validation_error, not_found, restricted_api_key, sending_paused, invalid_idempotent_request, …).
• e.status_code is the HTTP status, or None for client-side/transport failures (connection refused, DNS, timeout).

Subclasses: ValidationError, NotFoundError, RestrictedApiKeyError, SendingPausedError, InvalidIdempotentRequestError, ApplicationError, MissingApiKeyError.

Resources

Emails

millionsend.Emails.send(payload, idempotency_key="order-42")  # POST /emails
millionsend.Emails.get(email_id)                              # GET /emails/{id}
millionsend.Emails.cancel(email_id)                           # POST /emails/{id}/cancel (scheduled only)
millionsend.Batch.send([payload_a, payload_b], idempotency_key="batch-1")  # up to 100

to / cc / bcc / reply_to accept a string or a list of strings.

Audiences & contacts

audience = millionsend.Audiences.create({"name": "Registered users"})
millionsend.Audiences.list(limit=20)
millionsend.Audiences.get(audience.id)
millionsend.Audiences.remove(audience.id)

millionsend.Contacts.create({
    "audience_id": audience.id,
    "email": "ada@acme.dev",
    "first_name": "Ada",
    "properties": {"plan": "pro"},
})
millionsend.Contacts.get(audience_id=audience.id, email="ada@acme.dev")  # by id or email (email wins)
millionsend.Contacts.get("contact-id")                                   # bare id works too
millionsend.Contacts.update({"id": "contact-id", "unsubscribed": True, "first_name": None})  # None clears
millionsend.Contacts.remove(email="ada@acme.dev")
millionsend.Contacts.list(audience_id=audience.id, limit=50)

# Topic subscriptions (granular unsubscribe) — mirrors resend's contacts.topics.update
millionsend.Contacts.Topics.update({
    "email": "ada@acme.dev",
    "topics": [{"id": "topic-id", "subscription": "opt_out"}],
})

Reads, updates, and deletes also work without an audience (top-level /contacts). Creation always requires audience_id — the API answers 422 without it.

Topics

millionsend.Topics.create({"name": "Product updates", "default_subscription": "opt_in"})
millionsend.Topics.get(topic_id)
millionsend.Topics.list()      # bare {"data": [...]} — topics are unpaginated
millionsend.Topics.remove(topic_id)

Broadcasts

broadcast = millionsend.Broadcasts.create({
    "audience_id": audience.id,
    "from": "Acme <news@acme.dev>",
    "subject": "Launch",
    "html": "<p>Hi {{{FIRST_NAME|there}}}</p>",
})
millionsend.Broadcasts.list()
millionsend.Broadcasts.get(broadcast.id)
millionsend.Broadcasts.update(broadcast.id, {"subject": "Launch 🚀"})       # draft only
millionsend.Broadcasts.send(broadcast.id, scheduled_at="2026-09-01T09:00:00Z")  # omit to send now
millionsend.Broadcasts.cancel(broadcast.id)  # scheduled only
millionsend.Broadcasts.remove(broadcast.id)  # draft only

Segments (MillionSend extension)

Dynamic segments are a saved filter over an audience's contacts — a MillionSend feature with no Resend equivalent (the wire path is /segments2).

segment = millionsend.Segments.create({
    "name": "Pro plan",
    "audience_id": audience.id,
    "filter": {"match": "all", "conditions": [
        {"field": "property:plan", "op": "equals", "value": "pro"},
    ]},
})
millionsend.Segments.get(segment.id)   # includes a live contact_count
millionsend.Segments.list()
millionsend.Segments.update(segment.id, {"name": "Pro tier"})
millionsend.Segments.remove(segment.id)

Migrating from Resend

- import resend
- resend.api_key = "re_123"
+ import millionsend
+ millionsend.api_key = "ms_123"
+ millionsend.base_url = "https://mail.acme.dev"

- resend.Emails.send({...})
+ millionsend.Emails.send({...})

Method names and payloads match. Notes:

• Domains and API keys are managed in the MillionSend dashboard, not via the API, so there are no Domains / ApiKeys resources here.
• Resend's Segments is an alias of audiences; MillionSend's Segments is the distinct dynamic-filter feature. Use Audiences for a straight port.
• MillionSend raises on API errors just like resend; the exception carries .code / .status_code / .message.

License

MIT