LetterDuck
Guides

Email guides

Long-form, kept-current guides to the parts of email that decide whether your mail lands. Each one anchors a cluster of shorter pieces.

Field guide

Business email on your own domain: the complete setup guide

How to create a business email on your own domain: the exact MX, SPF, DKIM, and DMARC records, address setup, and the real per-seat cost math.

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Field guide

Cold email infrastructure that does not burn your domain

Cold outreach without wrecking the domain your business runs on: separate sending domains, real warm-up, complaint math, suppression, and reply handling.

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Field guide

The email deliverability handbook

The deliverability rules we run in production: aligned SPF, DKIM and DMARC, one-click unsubscribe, complaint math, warm-up ramps, and a $0 monitoring stack.

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Field guide

What email actually costs in 2026

Per-seat suites, per-contact platforms, and volume senders priced side by side at 1 to 10 seats and 500 to 10,000 subscribers, with every billing trap named.

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Field guide

How to start a newsletter you actually own

How to start a newsletter on a domain you own: DNS and authentication, double opt-in, a welcome sequence, steady cadence, and your first 500 subscribers.

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