[bjarn]

What changed

• WebhookEvent gains "inbound.rejected". Webhooks can subscribe to it, and the API sends it when an inbound message is rejected during SMTP.
• Only the generated types change. No new methods, no new fields, no signature changes.
• WebhookEvent already accepted unknown event names as str, so this only adds the literal for type checkers and documents the event.

Non-breaking. Target: minor.

API changes in the regenerated types

Type	Change	Python
WebhookEvent	gains the value inbound.rejected	Literal["inbound.rejected"] member

The spec's openapi version string moved from 3.1.0 to 3.1.2. That has no effect on the SDK.

Usage

lettermint.webhooks.create(
    {
        "name": "Rejected inbound mail",
        "url": "https://example.com/webhooks/lettermint",
        "events": ["inbound.rejected"],
    }
)

# In the webhook handler:
webhook = Webhook(os.environ["LETTERMINT_WEBHOOK_SECRET"])
event = webhook.verify(raw_body, headers)
if event["event"] == "inbound.rejected":
    ...

Checks

Python 3.14.6, after pip install -e ".[dev]":

• python -m ruff check src tests scripts: passed
• python -m ruff format --check src tests scripts: 28 files already formatted
• python -m mypy: no issues in 35 source files
• python scripts/unasync.py --check: _sync up to date
• python scripts/generate.py --check: generated files up to date with the pinned spec. The header-only mode that CI runs also passes.
• python -m pytest tests/: 305 passed

The same test job (ruff, mypy, unasync and generate checks, pytest) on Python 3.10.20, 3.11.13, 3.12.11 and 3.13.4: passed, 305 tests each.

Build job, Python 3.12.11:

• python -m build: sdist and wheel built
• python -m twine check --strict dist/*: passed
• installed the wheel in a fresh venv and ran the CI smoke script: UPGRADE.md and py.typed present, client constructs

Not run locally

Nothing. Every CI step was run locally.

Suggested release tag

v3.3.0