nanoPost

The WordPress Email Authority

FREE expert advice on setup, maintenance, and troubleshooting

Your WordPress email problems solved

Welcome to nanoPost, or, as we’d like to think of ourselves, The WordPress Email Authority. Our mission is to help you solve your WordPress email problems, whether it’s setting up, maintaining, or troubleshooting. Our expert guides, Q&A, reviews, and news on WordPress SMTP, contact forms, and more are here to provide you make the best choices.

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    Recently Updated

    • Free SMTP Servers for WordPress

      Thirteen free SMTP options for WordPress, ranked by whether the $0 tier is actually permanent. Permanent free plans, trials, and testing sandboxes – separated.

    • WP Mail SMTP Review

      The most-installed WordPress mailer plugin (4M+ sites). Broad mailer support and a setup wizard that works. Email logging requires the Pro plan ($99/year on renewal).

    • WordPress hosts where wp_mail works without a plugin

      Seven WordPress hosts route wp_mail through a signed relay by default. Password resets land without a mailer plugin. Which to pick, when, and why.

    • Best WordPress SMTP plugins: WP Mail SMTP vs FluentSMTP vs Post SMTP

      WP Mail SMTP, FluentSMTP, and Post SMTP compared by use case. Free vs paid feature splits, where each plugin is the wrong choice, and the also-rans.

    • Debugging WordPress SMTP OAuth setups with Postman

      Validate a Microsoft 365 or Google Workspace OAuth registration in Postman before wiring the client ID and secret into WP Mail SMTP, FluentSMTP, or Post SMTP.

    • Reading SMTP bounce codes in WordPress mailer logs

      Decoding the SMTP bounce codes WP Mail SMTP, FluentSMTP, and Post SMTP log – numeric code, enhanced status code, and Gmail/M365 variations.

    • Microsoft 365 as a WordPress SMTP Server

      Microsoft 365 can relay WordPress mail through Exchange Online via SMTP AUTH or OAuth. Per-mailbox cap is 10,000 recipients per day, 30 messages per minute. SMTP AUTH Basic Authentication is default-off on existing tenants from the end of December 2026; OAuth is the only path that survives the cutoff.

    • Resend as a WordPress SMTP Server

      Resend is the React Email team’s developer-first sending service: generous free tier, clean API. For WordPress operators, does the developer pitch translate?

    • Postmark as a WordPress SMTP Server

      Postmark review, for WordPress: pricing from $15/mo for 10,000, stream separation, WP Mail SMTP setup. The right transactional default.

    • SendGrid as a WordPress SMTP server

      SendGrid is a high-volume email platform owned by Twilio. Essentials plan starts at $19.95/month for 50,000 emails. Priced and featured above what most WordPress sites need, but a defensible choice at enterprise scale.

    • Bird (formerly MessageBird, formerly SparkPost) as a WordPress SMTP server

      SparkPost operates as Bird’s email product after the 2022 acquisition. Self-service Starter ($20/mo) and Premier ($75/mo, dedicated IP included) tiers are back; Enterprise handles 5M+/mo. The official WordPress plugin remains closed as of March 2025.

    • Mailjet as a WordPress SMTP Server

      Mailjet’s free tier sends 6,000 emails/month from WordPress. A marketing platform with decent SMTP, but Brevo’s free tier is more generous and the Mailjet branding on free emails is a drawback.