Quick comparison
An email API is the fastest way to send transactional email from Python. Here is how the top providers compare.
| Provider | Free tier | Starter | Pro | SDK | SMTP | Campaigns |
|---|---|---|---|---|---|---|
| RelayPost | 1,000/mo | $5/10K | $25/100K | requests (native) | Yes | Yes |
| Resend | 3,000/mo | $20/50K | $90/100K | pip package | Yes | Yes (Broadcasts) |
| Postmark | 100/mo | $15/10K | $16.50/10K | pip package | Yes | Yes (Bulk API) |
| SendGrid | 100/day | $20/40K | $90/100K | pip package | Yes | Yes |
| Mailgun | 100/day (trial) | $35/50K | $90/100K | pip package | Yes | Yes |
1. RelayPost — best overall for Python
RelayPost works with Python's standard requests library. No SDK to install, no new abstractions to learn. It handles both transactional and campaign email in a single API.
import requests
import os
response = requests.post(
"https://api.relaypost.dev/v1/emails/send",
headers={
"Content-Type": "application/json",
"Authorization": f"Bearer {os.environ['RELAYPOST_API_KEY']}",
},
json={
"from": {"email": "[email protected]", "name": "YourApp"},
"to": [{"email": "[email protected]"}],
"subject": "Welcome to YourApp",
"html": "<h1>Welcome!</h1><p>Your account is ready.</p>",
},
)
print(response.json()["data"]["message_id"])Strengths: no dependencies beyond requests, transparent pricing ($5/10K emails), transactional + campaigns, SMTP fallback for Django.
2. Resend — clean API, growing feature set
Resend has a well-designed Python SDK. They now support SMTP relay and broadcast email via Audiences, expanding beyond their transactional-only roots.
import resend
resend.api_key = "re_123456789"
params = {
"from": "[email protected]",
"to": ["[email protected]"],
"subject": "Welcome",
"html": "<p>Welcome to YourApp</p>",
}
email = resend.Emails.send(params)Strengths: clean SDK design, Audiences for broadcasts. Weaknesses: higher pricing at scale, 100/day cap on free tier, SMTP support is newer.
3. Postmark — fastest transactional delivery
Postmark (owned by ActiveCampaign) delivers industry-leading delivery speed. They recently added a Bulk API for marketing/broadcast email alongside their core transactional service.
from postmarker.core import PostmarkClient
postmark = PostmarkClient(server_token="your-server-token")
postmark.emails.send(
From="[email protected]",
To="[email protected]",
Subject="Welcome",
HtmlBody="<p>Welcome to YourApp</p>",
)Strengths: delivery speed, reputation, new Bulk API. Weaknesses: tiered pricing starts at $15/10K, limited free tier (100 emails/mo), dedicated IPs require 300K+/mo.
4. SendGrid — established but complex
SendGrid (Twilio) is the most established email API. It supports transactional and marketing email but has a verbose SDK and confusing pricing.
from sendgrid import SendGridAPIClient
from sendgrid.helpers.mail import Mail
message = Mail(
from_email="[email protected]",
to_emails="[email protected]",
subject="Welcome",
html_content="<p>Welcome to YourApp</p>",
)
sg = SendGridAPIClient(os.environ.get("SENDGRID_API_KEY"))
response = sg.send(message)Strengths: feature-complete, large ecosystem. Weaknesses: verbose SDK, confusing pricing, declining DX.
5. Mailgun — reliable, enterprise-focused
Mailgun (Sinch) is solid for teams that need advanced routing and deliverability features. The Python SDK works but feels more enterprise than developer-first.
import requests
import os
response = requests.post(
"https://api.mailgun.net/v3/yourapp.com/messages",
auth=("api", os.environ["MAILGUN_API_KEY"]),
data={
"from": "[email protected]",
"to": ["[email protected]"],
"subject": "Welcome",
"html": "<p>Welcome to YourApp</p>",
},
)Strengths: advanced routing, good deliverability. Weaknesses: complex pricing, trial-only free tier.
Django integration comparison
Django has built-in SMTP email support. Any provider with SMTP works out of the box with Django's send_mail().
# settings.py — works with RelayPost, Postmark, SendGrid, Mailgun
EMAIL_BACKEND = "django.core.mail.backends.smtp.EmailBackend"
EMAIL_HOST = "smtp.relaypost.dev" # or smtp.postmarkapp.com, smtp.sendgrid.net
EMAIL_PORT = 587
EMAIL_USE_TLS = True
EMAIL_HOST_USER = os.environ["SMTP_USERNAME"]
EMAIL_HOST_PASSWORD = os.environ["SMTP_PASSWORD"]For the REST API approach, call the provider's API directly with requests in your views, or use django-anymail for a unified interface across providers.
How to choose
- Need transactional + campaigns in one API? → RelayPost
- Want the cleanest SDK and only send transactional? → Resend
- Fastest transactional delivery is the top priority? → Postmark
- Need enterprise features and don't mind complexity? → SendGrid or Mailgun
- Using Django and want zero-config SMTP? → RelayPost or Postmark
- Budget-conscious with high volume? → RelayPost ($25/100K vs $70-90/100K elsewhere)
Frequently asked questions
What is the best email API for Python?
RelayPost, Resend, and Postmark are the top choices for Python developers. RelayPost works with the standard requests library (no SDK needed), supports both transactional and campaign email, and has the most affordable pricing at scale. Resend now offers broadcasts via Audiences. Postmark recently added a Bulk API for marketing email.
Do I need an SDK to send email from Python?
No. Most email APIs accept a simple HTTP POST request. Python's requests library is all you need. SDKs add convenience but also add a dependency. RelayPost is designed to work with requests out of the box.
Should I use smtplib or an email API?
Use an email API (REST) for new projects. It is simpler, gives you access to features like templates and tracking, and handles authentication automatically. Use smtplib only if your framework requires SMTP (like Django's built-in email backend).
Which email API works best with Django?
Django has built-in SMTP support, so any provider with SMTP works. RelayPost, Postmark, and SendGrid all support SMTP. For the REST API approach, use django-anymail or call the API directly with requests in your views.
Related resources
Try RelayPost free
1,000 emails per month on the free tier. No credit card required.
Create free account