local-letter

Render an email template from your local-letter project and send it through Resend — in one call.

Your templates and their translations live in the local-letter dashboard, so copy changes ship without a deploy. Your Resend key never leaves your server: the SDK renders against your API, then talks to Resend directly.

pip install local-letter

Requires Python 3.9+.

Usage

import os
from local_letter import TemplateClient

letters = TemplateClient(
    base_url="https://letters.yourcompany.com",
    api_key=os.environ["LOCAL_LETTER_API_KEY"],
    resend_api_key=os.environ["RESEND_API_KEY"],
    from_="hello@yourcompany.com",
)

result = letters.send(
    template="welcome-email",
    to="customer@example.com",
    variables={"first_name": "Sagar"},
)

print(result.id)  # Resend message id

variables fill {{token}} placeholders in the template's subject and body. A token you don't supply is left in place rather than blanked, so a missing variable shows up in the output instead of vanishing silently.

Localisation

Pass the recipient's locale and a fallback. The API normalises casing, so en-us and EN-US both match en-US:

result = letters.send(
    template="welcome-email",
    to=user.email,
    variables={"first_name": user.first_name},
    locale=user.locale,          # "fr" — uses the French version if it exists
    fallback_locale="en",        # otherwise English, then the template default
)

result.locale tells you which version actually went out.

API

TemplateClient(base_url, api_key, resend_api_key, from_)

letters.send(...)

Returns a SendResult with id, subject, html, and locale — the Resend message id plus what was actually rendered.

Errors

Both error types are exported, so you can tell a template problem from a delivery problem:

from local_letter import TemplateRenderError, TemplateSendError

try:
    letters.send(template="welcome-email", to=user.email)
except TemplateRenderError as err:
    # Your API rejected the render. err.status: 401 bad key, 404 no such
    # template, 403 key not linked to a project.
    ...
except TemplateSendError as err:
    # Rendered fine, Resend refused it — often an unverified sender domain.
    # err.cause holds Resend's own exception.
    ...

Examples

Runnable integrations live in examples/.

License

MIT