drin-email-best-practices

Get transactional email deliverability right with Drin — authenticate the sending domain (SPF/DKIM/DMARC), stay under bounce/complaint limits, honor suppressions, and include one-click unsubscribe where required. Use when setting up a sending domain, diagnosing why mail lands in spam or bounces, deciding sending volume/warmup, or reviewing an email program for compliance and reputation.

Email deliverability & compliance with Drin

Reputation is everything. One sloppy send can tank an entire domain's inbox placement. Follow these before and during any sending program.

1. Authenticate the domain (do this first)

Email is only trusted when the sending domain is authenticated.

• Add the domain: add_domain / POST /v1/domains / dashboard. Drin returns the exact DNS records to publish.
• Publish all returned records:
  • DKIM — Drin signs with the domain's own key (records provided). This is what makes the mail cryptographically yours.
  • SPF / MAIL FROM — authorizes the sending path.
  • DMARC — start at p=none to monitor, then move to p=quarantine → p=reject once aligned and clean. Publish a rua= to receive reports.
• Confirm verification: get_domain / GET /v1/domains/:id and check each record's verified: true. Do not send real mail until the domain is verified.

Prefer a subdomain for sending (e.g. mail.acme.com / notifications.acme.com) so transactional reputation is isolated from your root domain's other mail.

2. Stay under the hard limits

Mailbox providers (and Drin's own circuit breaker) watch these rates. Crossing them throttles or suspends sending:

• Bounce rate < 4% (aim < 2%). High bounces = bad list hygiene.
• Complaint (spam) rate < 0.1% (aim < 0.05%). High complaints = unwanted mail.

Monitor continuously with get_metrics / GET /v1/metrics. If a rate climbs, stop and investigate — don't keep sending.

3. Honor suppressions — never bypass them

Drin automatically suppresses an address after a hard bounce or a spam complaint, and refuses (409 suppressed) further sends to it. This protects your reputation. Rules for an agent:

• Never "retry around" a suppression or strip it to force a send.
• Treat unsubscribe / "stop emailing me" requests as add_suppression.
• Inspect with list_suppressions; only remove_suppression on a genuine, verified opt-back-in.

4. List hygiene & content

• Send to addresses that opted in or that you have a transactional relationship with. Don't email purchased/scraped lists.
• Validate addresses at capture time; don't send to obviously invalid ones.
• Keep a real text part, a clear from name, a truthful subject (no clickbait/ALL CAPS/excessive emoji), and a visible physical identity where required.
• Match the from domain to the brand the recipient expects (alignment).

5. Unsubscribe (bulk / marketing-adjacent mail)

For anything beyond strictly 1:1 transactional mail, include a working unsubscribe. Drin supports RFC 8058 one-click unsubscribe and a hosted /unsubscribe flow — include the unsubscribe link/headers and honor opt-outs immediately (they become suppressions). Transactional receipts/OTPs/password resets generally don't need an unsubscribe, but must not contain marketing.

6. Warm up new domains/volume

A brand-new domain has no reputation. Ramp gradually (start with low daily volume to your most engaged recipients, increase over days/weeks) rather than blasting from day one. Drin's per-tenant trust engine ramps new senders automatically — don't try to defeat it; let reputation build.

Quick checklist before a campaign or new integration

• Domain verified (get_domain shows DKIM/SPF/DMARC verified: true).
• DMARC at least p=none with rua= reporting.
• Sending from a subdomain dedicated to this mail stream.
• text part present; subject honest; from-name set.
• Recipients opted in / transactional; list cleaned.
• Unsubscribe present for non-1:1 mail.
• Baseline get_metrics captured; bounce/complaint alerts in mind.