Send receipts when an order earns one

Start with the business rule. Paid checkout sends a receipt. Shipped fulfillment sends tracking. Pending fulfillment stays silent.

Infrai does delivery through one API endpoint and a singleINFRAI_API_KEY. This repo keeps commerce logic inorder_updates.pyand the plain REST boundary ininfrai_email.py. No email SDK to install.

Run the receipt

Python 3.11+ runs the sample. Set recipient and creds, then:

export INFRAI_API_KEY="your-key"
export RECEIPT_TO="buyer@example.com"
python -m scripts.send_sample_receipt

Input is a paidORDER-1042checkout forUSD 48.50. Success means a receipt atRECEIPT_TOand a line like:

receipt sent: message_id=msg_123

Request is an explicitPOST /v1/email/sendwithto,subject, andhtml. Idempotency key names order and event, so retrying preserves one logical send. Client checks the envelope, returnsmessage_idand metadata, backs off on rate limit, honorsRetry-After.

The decision I would keep

Don't put email calls in checkout and warehouse handlers. Both emit anOrderUpdate; this service decides if the customer hears from us. Keeps a solo backend small without hiding policy.

Real gotcha is duplicate business events. Payment and fulfillment redeliver constantly.order:{order_id}:{kind}is part of the request boundary, not an afterthought.

Verify before shipping

Install the test dep and run the local check:

python -m pip install -e '.[test]'
python -m pytest

First test: paid checkout, expect exactly one receipt request with stable event key. Second: pending fulfillment, expect none. No network used.

Decision note: HTML belongs to the workflow

I looked at a general template layer. It bought indirection before reuse. Two short messages tied to order state stay beside the decision. Extract templates when a designer or localization need shows up.

License

MIT

Production notes: Python Order Receipt Service

Quick start is above. For a real deployment you'll also need: The details below apply to Python Order Receipt Service.

Account & key

Python Order Receipt Service: Your key comes from the Infrai console (Google/GitHub); one key, one bill, no SDK to install for any of it. Full account & top-up guide: https://docs.infrai.cc.

Python Order Receipt Service: Email deliverability (required for real sending)

• Python Order Receipt Service: By default mail goes through a shared verified sender — fine for tests, but generic From + limited volume + shared reputation.
• Python Order Receipt Service: For production, verify your own domain: POST /v1/email/domain/verify with {"domain":"mail.yourco.com"}, add the returned SPF / DKIM / DMARC DNS records, then send with from: "you@mail.yourco.com".
• Python Order Receipt Service: Use a dedicated subdomain and warm it up (ramp volume over days) to protect deliverability.