eusend

Official Python SDK for the Eusend API — the EU-native transactional email platform.

Its shape mirrors resend-python, so migrating from Resend is largely a resend → eusend rename.

• Module-level config — eusend.api_key = "...", then call eusend.Emails.send(...).
• Zero HTTP dependencies — the transport is built on the standard library.
• Typed — TypedDict params and responses; ships py.typed.

pip install eusend

Requires Python 3.8+.

---

Getting started

import eusend

eusend.api_key = "eu_live_..."

params: eusend.Emails.SendParams = {
    # `from` accepts a bare email or a display-name form: "Acme <you@yourdomain.com>"
    "from": "Acme <you@yourdomain.com>",
    "to": ["user@example.com"],
    "subject": "Hello",
    "html": "<p>Hello world</p>",
}

email = eusend.Emails.send(params)
print(email["id"])  # 9a8b7c6d-... (UUID)

The key can also come from the EUSEND_API_KEY environment variable, in which case you can skip setting eusend.api_key.

Responses are dicts with snake_case keys — access fields with email["id"]. On failure, methods raise eusend.EusendError (see Error handling).

---

Emails

Send

from and to are required; provide at least one of html, text, or template_id.

Key	Type	Notes
from	str	Verified domain; bare or display-name form.
to cc bcc reply_to	str | list[str]	Max 50 each.
subject	str
html / text	str
template_id	str	Saved template.
variables	dict	Template substitutions (HTML-escaped).
headers	dict[str, str]	No line breaks in names or values.
track_opens / track_clicks	bool	Omit to use your organization default (Settings → General → Email tracking), off unless changed.
attachments	list[Attachment]	See below. Up to 20, 10 MB combined.
scheduled_at	str	Future send, ≤ 30 days.

Attachments

Each attachment is a dict. content accepts raw bytes (base64-encoded for you) or an already-base64 str; alternatively pass path (a public URL fetched at send time). Set content_id for an inline <img src="cid:...">.

with open("invoice.pdf", "rb") as f:
    eusend.Emails.send({
        "from": "you@yourdomain.com",
        "to": "user@example.com",
        "subject": "Your invoice",
        "html": "<p>Attached.</p>",
        "attachments": [
            {"filename": "invoice.pdf", "content": f.read(), "content_type": "application/pdf"},
        ],
    })

Idempotent sends

Pass an options dict with an idempotency_key to safely retry without duplicating:

eusend.Emails.send(
    {"from": "you@yourdomain.com", "to": "user@example.com",
     "subject": "Your receipt", "html": "<p>Thanks!</p>"},
    options={"idempotency_key": f"receipt-{order_id}"},
)

Scheduled sends

scheduled_at accepts an ISO 8601 string or natural language ("in 1 hour", "tomorrow at 9am"), parsed server-side in UTC.

sent = eusend.Emails.send({
    "from": "you@yourdomain.com", "to": "user@example.com",
    "subject": "Reminder", "html": "<p>Soon.</p>",
    "scheduled_at": "in 1 hour",
})

eusend.Emails.update({"id": sent["id"], "scheduled_at": "in 2 hours"})  # reschedule
eusend.Emails.cancel(sent["id"])                                        # cancel before it sends

Batch

Up to 100 emails in one request. Attachments and scheduling are stripped (not supported on the batch endpoint). The result maps positionally to the input: queued items carry id, rejected items carry error and code.

res = eusend.Batch.send([
    {"from": "you@yourdomain.com", "to": "alice@example.com", "subject": "Hi", "html": "<p>Hi</p>"},
    {"from": "you@yourdomain.com", "to": "bob@example.com",   "subject": "Hi", "html": "<p>Hi</p>"},
])
for item in res["data"]:
    print(item.get("id") or f"{item['code']}: {item['error']}")

Pass options={"idempotency_key": ...} as the second argument to retry a batch safely. The key is applied per item by position, so a retry must send the items in the same order.

eusend.Batch.send(emails, options={"idempotency_key": f"digest-{run_id}"})

Retrieve & list

email = eusend.Emails.get("9a8b7c6d-...")
print(email["status"], email["events"][0]["type"])

page = eusend.Emails.list({"limit": 20, "status": "delivered"})
for e in page["data"]:
    print(e["id"], e["subject"])
if page["next_cursor"]:
    page = eusend.Emails.list({"cursor": page["next_cursor"]})

Filter by status, from, to. Statuses: queued scheduled sending sent delivered bounced complained suppressed failed.

---

Domains

created = eusend.Domains.create("yourdomain.com")
print(created["dkim"]["name"], created["dkim"]["value"])  # DNS records to add
print(created["spf"], created["dmarc"])

eusend.Domains.verify(created["id"])   # after publishing the DNS records
eusend.Domains.list()
eusend.Domains.get(created["id"])
removed = eusend.Domains.remove(created["id"])
print(removed["canceled_scheduled_emails"])  # scheduled emails from the domain are canceled

---

API keys

key = eusend.ApiKeys.create({"name": "Production"})
print(key["key"])  # eu_live_... — returned only once

eusend.ApiKeys.create({"name": "Sandbox", "test_mode": True})  # eu_test_... key
eusend.ApiKeys.list()                                          # prefixes only
eusend.ApiKeys.remove(key["id"])

Emails sent with a test key are accepted and tracked but never delivered.

permission defaults to FULL_ACCESS — every resource. SENDING_ACCESS limits the key to sending email (plus rescheduling and canceling a scheduled send); every other endpoint, including reading email logs, returns 403 FORBIDDEN. Such a key can also be pinned to one sending domain with domain_id, which is rejected on a full-access key.

eusend.ApiKeys.create({
    "name": "Billing service",
    "permission": eusend.SENDING_ACCESS,
    "domain_id": domain_id,  # omit for any verified domain
})

Deleting a domain revokes every key restricted to it.

---

Audiences & contacts

Contact operations are grouped under Audiences (they live under a specific audience).

audience = eusend.Audiences.create("Newsletter")

eusend.Audiences.create_contact(
    audience["id"],
    {
        "email": "user@example.com",
        "first_name": "Jane",
        # Custom properties become {{plan}} in a broadcast body.
        "properties": {"plan": "pro"},
    },
)

# Bulk upsert (up to 1,000) → {"count": N}
eusend.Audiences.batch_create_contacts(audience["id"], [
    {"email": "alice@example.com", "first_name": "Alice"},
    {"email": "bob@example.com", "first_name": "Bob"},
])

page = eusend.Audiences.list_contacts(audience["id"], {"subscribed": True, "search": "gmail.com"})
contact = page["data"][0]

eusend.Audiences.update_contact(audience["id"], contact["id"], {"unsubscribed": True})
eusend.Audiences.get_contact(audience["id"], contact["id"])
eusend.Audiences.remove_contact(audience["id"], contact["id"])

eusend.Audiences.list()
eusend.Audiences.get(audience["id"])   # includes contact_count
eusend.Audiences.update(audience["id"], {"name": "Product updates"})
eusend.Audiences.remove(audience["id"])

Contact properties

The custom fields your contacts carry. Declaring one is optional — a property you send on a contact registers itself as a string — but a declared property can have a type and a fallback rendered for contacts that have no value of their own.

eusend.ContactProperties.create({"key": "plan", "type": "string", "fallback_value": "free"})

properties = eusend.ContactProperties.list()
eusend.ContactProperties.get(properties[0]["id"])

# The fallback is the only mutable field: key and type are fixed at creation.
eusend.ContactProperties.update(properties[0]["id"], {"fallback_value": "trial"})

# Deletes the definition AND strips the key from every contact. Not undoable.
eusend.ContactProperties.remove(properties[0]["id"])

---

Suppressions

Addresses the account will not send to. Hard bounces and spam complaints are added automatically; these methods cover the ones you manage yourself. A send to a suppressed address is skipped and recorded with status suppressed; if every recipient is suppressed the send fails with ALL_SUPPRESSED.

Test-mode keys can read the list but not modify it.

# Everything suppressed for a hard bounce, or at one domain
page = eusend.Suppressions.list({"reason": "bounce", "limit": 50})
eusend.Suppressions.list({"email": "@acme.com"})

# Suppress an address. Already suppressed? The existing entry comes back unchanged —
# a manual add never rewrites a real bounce or complaint.
eusend.Suppressions.create({"email": "opted-out@example.com"})

# Import up to 1,000 at a time — do this before your first send when migrating, so
# addresses that already bounced elsewhere don't get a fresh attempt from a new IP.
# (Named import_list because `import` is a Python keyword.)
res = eusend.Suppressions.import_list([
    "one@example.com",
    {"email": "two@example.com", "reason": "complaint"},
])
print(res["count"], res["already_suppressed"], res["duplicates"])

# Un-suppress by entry id or by address
eusend.Suppressions.remove("invalid@example.com")

# The whole list as CSV (bytes)
csv = eusend.Suppressions.export()

---

Templates

{{variable}} placeholders are substituted at send time; values are HTML-escaped.

tpl = eusend.Templates.create({
    "name": "Welcome email",
    "subject": "Welcome, {{name}}!",
    "html": "<h1>Hi {{name}}</h1><p>Welcome to {{product}}.</p>",
})

eusend.Emails.send({
    "from": "you@yourdomain.com", "to": "user@example.com",
    "template_id": tpl["id"],
    "variables": {"name": "Jane", "product": "Acme"},
})

eusend.Templates.list()
eusend.Templates.get(tpl["id"])
eusend.Templates.update(tpl["id"], {"subject": "New subject"})
eusend.Templates.remove(tpl["id"])

---

Webhooks

hook = eusend.Webhooks.create({
    "url": "https://yourapp.com/webhooks/eusend",
    "events": ["email.delivered", "email.bounced", "email.complained"],  # or ["*"]
})
print(hook["secret"])  # signing secret — returned only once

eusend.Webhooks.list()
eusend.Webhooks.get(hook["id"])   # includes recent deliveries
eusend.Webhooks.update(hook["id"], {"events": ["email.bounced"]})
eusend.Webhooks.remove(hook["id"])

Events: email.sent email.delivered email.bounced email.complained email.opened email.clicked email.failed email.suppressed. The endpoint must be a public http(s) URL returning 2xx directly (redirects count as failures).

Verifying signatures

Every delivery is signed with HMAC-SHA256 over {webhook-id}.{webhook-timestamp}.{body}:

import base64
import hashlib
import hmac

def verify(headers, body: bytes, secret: str) -> bool:
    signed = f"{headers['webhook-id']}.{headers['webhook-timestamp']}.{body.decode()}"
    mac = hmac.new(secret.encode(), signed.encode(), hashlib.sha256)
    expected = "v1," + base64.b64encode(mac.digest()).decode()
    return hmac.compare_digest(headers["webhook-signature"], expected)

---

Broadcasts

Send one email to every contact in an audience. {{first_name}}, {{last_name}}, {{full_name}}, and {{email}} are available per recipient, and RFC 8058 one-click unsubscribe headers are added automatically.

bc = eusend.Broadcasts.create({
    "name": "May newsletter",
    "audience_id": audience["id"],
    "from": "Sivert <hello@yourdomain.com>",
    "reply_to": "support@yourdomain.com",
    "subject": "May update",
    "html": "<p>Hi {{first_name}}, your monthly update is here...</p>",
})

eusend.Broadcasts.send(bc["id"])                                  # send now
eusend.Broadcasts.send(bc["id"], {"scheduled_at": "2026-06-01T09:00:00Z"})  # or schedule
eusend.Broadcasts.cancel(bc["id"])

eusend.Broadcasts.list()
eusend.Broadcasts.get(bc["id"])   # includes delivery stats
eusend.Broadcasts.update(bc["id"], {"subject": "Updated subject"})
eusend.Broadcasts.remove(bc["id"])

Calling send on a paused broadcast resumes it from where it stopped.

---

Error handling

Any non-2xx response raises a subclass of eusend.EusendError. Network failures that never reach the server raise ApplicationError (with status_code == None).

import eusend
from eusend import EusendError, RateLimitError

try:
    eusend.Emails.send({"from": "you@yourdomain.com", "to": "user@example.com",
                        "subject": "Hi", "html": "<p>Hi</p>"})
except RateLimitError as e:
    print(e.code)         # "MONTHLY_LIMIT_EXCEEDED"
    print(e.status_code)  # 429
except EusendError as e:
    print(e.code, e.message, e.status_code)

Exception classes: MissingApiKeyError, InvalidApiKeyError, ValidationError, NotFoundError, RateLimitError, ApplicationError — all subclasses of EusendError. Branch on e.code:

Code	Status	Exception
UNAUTHORIZED	401	InvalidApiKeyError
FORBIDDEN	403	EusendError
NOT_FOUND	404	NotFoundError
VALIDATION_ERROR / BAD_REQUEST	400	ValidationError
CONFLICT	409	EusendError
RATE_LIMITED	429	RateLimitError
MONTHLY_LIMIT_EXCEEDED	429	RateLimitError
DAILY_LIMIT_EXCEEDED	429	RateLimitError
PLAN_LIMIT_EXCEEDED	403	EusendError
DOMAIN_NOT_VERIFIED	403	EusendError
SENDING_SUSPENDED	403	EusendError
LIST_SEND_HELD	403	EusendError
BROADCAST_HELD	403	EusendError
ALL_SUPPRESSED	422	EusendError
SERVICE_PAUSED	503	EusendError
INTERNAL_ERROR	500	ApplicationError
application_error	—	ApplicationError (network failure)

---

Configuration

import eusend

eusend.api_key = "eu_live_..."             # or EUSEND_API_KEY
eusend.api_url = "https://api.eusend.dev"  # override for testing