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

Release files for lettr 1.7.0

For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.

Source distribution (sdist)

Source distribution for lettr 1.7.0
File	Size	Uploaded
lettr-1.7.0.tar.gz	60.1 kB	Sep 22, 2026	Details

Built distribution (wheel)

Table of built distributions (wheels) for lettr 1.7.0
File	Interpreter	ABI	Platform	Reset
lettr-1.7.0-py3-none-any.whl 40.5 kB Sep 22, 2026	Python 3	none	any	Details

Total release size: 100.5 kB

Release files / lettr-1.7.0.tar.gz

Download URL	lettr-1.7.0.tar.gz
Size	60.1 kB
Tags	Source
SHA-256 checksum How to use checksums	`d2eb6070acb22bfc2b379c72dcc964f11ba491fe13230d9037c67e543ff6f767`
BLAKE2b-256 checksum How to use checksums	`a6ff3fb77773eccb0738b7f4e1efc02069dd7d4067d78089613e9d3682bf5ad9`
Upload date	Sep 22, 2026
Uploaded using Trusted Publishing? What is trusted publishing?	Yes
Uploaded via	`twine/7.0.0 CPython/3.13.14`

Provenance

Provenance describes where a file came from. On PyPI, provenance is shared via attestations, which provide a verifiable record of the build or publishing details. View details, limitations and caveats.

Identity

Publishing platform: GitHub Actions
Publishing repository: github.com/lettr-com/lettr-python
Publishing commit: github.com/lettr-com/lettr-python/tree/fd0ec958106f024e9d1f2841ae8d40d06e7fa0df

Workflow

Publishing configuration: github.com/lettr-com/lettr-python/blob/fd0ec958106f024e9d1f2841ae8d40d06e7fa0df/.github/workflows/publish.yml
Publishing logs: github.com/lettr-com/lettr-python/actions/runs/35724561159/attempts/1

Artifact

Subject: lettr-1.7.0.tar.gz
SHA-256 checksum: d2eb6070acb22bfc2b379c72dcc964f11ba491fe13230d9037c67e543ff6f767 Verifying attestations

Release files / lettr-1.7.0-py3-none-any.whl

Download URL	lettr-1.7.0-py3-none-any.whl
Size	40.5 kB
Tags	Python 3
SHA-256 checksum How to use checksums	`98d2b927aa4a0ea7a42a10cab444b6ad3922c2502a3d2eef96742df674c93261`
BLAKE2b-256 checksum How to use checksums	`7b7338836c3f515f6a3b49dd9c32139ad54c250f6b3e3c0ba5c98dd4cd267fd8`
Upload date	Sep 22, 2026
Uploaded using Trusted Publishing? What is trusted publishing?	Yes
Uploaded via	`twine/7.0.0 CPython/3.13.14`

Provenance

Identity

Publishing platform: GitHub Actions
Publishing repository: github.com/lettr-com/lettr-python
Publishing commit: github.com/lettr-com/lettr-python/tree/fd0ec958106f024e9d1f2841ae8d40d06e7fa0df

Workflow

Publishing configuration: github.com/lettr-com/lettr-python/blob/fd0ec958106f024e9d1f2841ae8d40d06e7fa0df/.github/workflows/publish.yml
Publishing logs: github.com/lettr-com/lettr-python/actions/runs/35724561159/attempts/1

Artifact

Subject: lettr-1.7.0-py3-none-any.whl
SHA-256 checksum: 98d2b927aa4a0ea7a42a10cab444b6ad3922c2502a3d2eef96742df674c93261 Verifying attestations