Deliverability

Getting accepted by the API is the easy part. Landing in the inbox is a reputation game decided by mailbox providers — and reputation is earned with authenticated, wanted, low-complaint mail sent at a steady pace. Drin handles the infrastructure side; this page covers the practices that are yours to keep. Mailbox providers like Gmail and Outlook score every sender on a few signals: are you who you say you are (authentication), do people want your mail (engagement and complaints), and do you send to real, reachable addresses (bounces and hygiene). Do well on all three and you reach the inbox. Slip on any one and you land in spam — or get blocked.

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Authentication alignment

When you verify a domain Drin sets up DKIM, a custom MAIL FROM (SPF), and DMARC — the three checks every receiver runs. The word that matters is alignment: it isn’t enough to pass DKIM and SPF, the domains they pass for must match the domain in your From address.

• DKIM alignment — your message is signed with a key under your own domain, so the DKIM domain matches your From. Drin’s BYODKIM setup gives you this by default.
• SPF alignment — the custom MAIL FROM puts the envelope sender on a send. subdomain of yours, so SPF aligns too (and no third-party sending service shows in your headers).
• DMARC — passes when either aligned DKIM or aligned SPF passes. With Drin’s setup you get both, so DMARC is solid.

DMARC starts at p=none so you can monitor without risk. Once you’ve confirmed all your legitimate mail passes, tighten the policy to p=quarantine and eventually p=reject for the strongest protection against spoofing.

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Warm up a new domain

A brand-new domain has no sending history, so providers are cautious. Don’t send your largest blast on day one. Ramp volume gradually over the first couple of weeks while engagement builds your reputation. New Drin domains ramp under a graduated daily cap that loosens automatically as your sending reputation establishes — so the platform warms with you rather than letting a cold domain over-send on day one.

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Stay under bounce & complaint limits

Two rates decide whether providers keep accepting your mail. Keep both well under their ceilings — not at the line, under it: These are account-wide reputation metrics, shared across everything you send. A single bad campaign can drag down your transactional mail too.

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Suppression

The fastest way to wreck a bounce rate is to keep mailing addresses that already bounced. Drin keeps a per-project suppression list and adds addresses to it automatically on a hard bounce or a spam complaint, so you never re-send into a wall. If every recipient of a send is suppressed, the request is rejected with a suppressed error and nothing goes out.

• Don’t fight it. Removing an address from suppression to re-send to a known-bad inbox just generates another bounce. Only resubscribe an address you have a clear reason to believe is now valid.
• Suppress proactively. If you learn an address is dead from your own systems, add it to the list yourself rather than waiting for the bounce.

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Unsubscribe

For any mail a person might not want every time, give them a one-click way out. Drin injects standards-based List-Unsubscribe and List-Unsubscribe-Post headers so Gmail and Outlook render a native unsubscribe link — the kind recipients use instead of hitting “spam.”

• Honor it instantly. An unsubscribe must stop the mail, full stop. Sending after an opt-out is the surest path to complaints.
• Use it as a release valve. An easy unsubscribe is a gift to your reputation: every person who unsubscribes is a person who didn’t mark you as spam.
• Purely transactional mail (password resets, receipts) generally doesn’t need a visible unsubscribe — but never smuggle marketing into a transactional message to dodge the requirement.

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Content & list hygiene

Even perfectly authenticated mail lands in spam if the content or the list looks like spam. The basics:

• Only mail people who asked. Permission is the single biggest deliverability factor. Never buy, scrape, or rent lists — they bounce hard and complain harder.
• Confirm new addresses. A confirmed opt-in (the user clicks a link in a first email) keeps typo and trap addresses off your list from the start.
• Prune disengagement. Stop mailing addresses that haven’t opened or clicked in months. Dead weight lowers your engagement signal and raises your spam-trap risk.
• Balance the message. Real text, a clear sender name, a working unsubscribe, and no link shorteners or all-image bodies. Plain, honest mail clears filters that flashy mail trips.
• Stay consistent. Steady volume from a stable From domain reads as a healthy sender. Long silences followed by huge blasts read as a compromised one.