The smtplib way, and what it costs you
Every Python email tutorial starts the same way: import smtplib, connect to smtp.gmail.com, pick port 587 or 465, generate an app password, build a MIME message. It works, on your machine, today.
Then the app password expires. Or port 25 is blocked on the server. Or Gmail's daily cap hits, because that cap was built for a person, not a product. smtplib sends mail; it does nothing for deliverability, tracking, or what happens after the send.
One POST, and the send is handled
import requests requests.post( "https://api.nitrosend.com/v1/my/messages", headers={"Authorization": "Bearer $NITROSEND_API_KEY"}, json={ "from": "[email protected]", "to": "[email protected]", "subject": "Welcome", "html": "<p>You're in.</p>", }, )
That is the whole integration. The requests library you already have, a bearer token from the environment, and a JSON body. SPF, DKIM, and DMARC are handled on the platform side, which is the part that decides whether your email lands in the inbox.
And before anything ships, run my preflight. Resolve every wrapped CTA URL, check the spam score, weigh images against text, lint for dark mode, and send a test to a seed address. Some platforms build this in. If yours doesn't, do it yourself, every time.
The API also takes a dry_run flag: pass it and the call validates recipients and configuration without sending anything, which is exactly what you want in a test suite. Treat it as a check on the request, not a guarantee about delivery. I've watched a dry run validate cleanly and the real send still fail on something the environment only reveals live, which is why the seed-address test stays in my preflight no matter what the validator says.
Full parameters, responses, and error codes live in the REST API docs and the API reference.
And the part no library gives you
The same account exposes an MCP server, so the agent writing your code can also run your email. Point Claude, Cursor, or Codex at api.nitrosend.com/mcp and it composes, previews, and stages sends, with a human approving every one. The API is for your code. The MCP is for your agent. One platform either way.
Every send comes back with a message ID, and delivery events follow on your webhook: delivered, opened, bounced. No dashboard required to know what happened.