Lettr for Python SDK

The official Python SDK for the Lettr Email API. A clean, typed client for emails, templates, domains, webhooks, audience, and campaigns — methods raise typed exceptions on failure.

Installation

pip install lettr

Quick Start

import lettr

client = lettr.Lettr("lttr_your_api_key")

response = client.emails.send(
    from_email="you@example.com",
    to=["user@example.com"],
    subject="Hello from Lettr!",
    html="<h1>Welcome!</h1>",
)

print(response.request_id)

Use the client as a context manager to close the connection pool automatically:

with lettr.Lettr("lttr_your_api_key") as client:
    client.emails.send(from_email="you@example.com", to=["user@example.com"],
                       subject="Hello!", html="<p>Hello!</p>")

Error Handling

The SDK raises typed exceptions — all subclasses of lettr.LettrError:

try:
    client.emails.send(from_email="you@example.com", to=["user@example.com"],
                       subject="Hello", html="<p>Hello!</p>")
except lettr.ValidationError as e:
    print(e.message, e.errors)
except lettr.LettrError as e:
    print(e.message)

See Error Handling for the full exception hierarchy.

Documentation

Full guides for every resource, with complete request/response details, live in the docs:

📚 docs.lettr.com/quickstart/python

Topic	Guide
Install, client setup, sending	Quickstart
Async, Django, error handling, type hints	Advanced
Manage Lettr templates & merge tags	Templates
Add, verify, and manage sending domains	Domains
Webhook endpoints for delivery & engagement events	Webhooks
Lists, contacts, topics, properties, segments	Audience
List, send, and schedule campaigns	Campaigns
Flask & FastAPI integration	Flask · FastAPI
Endpoint reference (params & schemas)	API Reference

Requirements

• Python 3.8+
• httpx (installed automatically)

License

MIT