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Improve email deliverability

Improve email deliverability for Fileflare’s download emails with SMTP setup and best practices.

Beka Rice Avatar

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Beka Rice

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Fileflare’s default email sender is already configured for high deliverability — DKIM, SPF, DMARC, and sender reputation are all in place. If you’re sending from your own domain via SMTP, you become responsible for the same authentication, and skipping any of it puts your emails in spam folders.

This guide is for stores using their own domain via SMTP. If you’re using Fileflare’s default sender, deliverability is handled for you — no action needed. DNS changes can break your domain if done wrong; consider hiring an admin or developer if you’re not confident.

When you’d use this

  • You’ve connected SMTP and want to set up your domain for best deliverability before sending real customer emails.
  • Customers report download emails landing in spam.
  • You’re sending more than ~5,000 emails per day and need to set up reverse DNS.
  • You want to align your domain to current Gmail and Yahoo bulk-sender requirements.

The three records that matter

DKIM (DomainKeys Identified Mail)

A cryptographic signature added to your email headers proving the email actually came from your domain. Your SMTP provider (Postmark, SendGrid, etc.) gives you a TXT record to add to your DNS. Without DKIM, your emails are much more likely to land in spam.

SPF (Sender Policy Framework)

A DNS TXT record listing every server allowed to send email on behalf of your domain. Receiving servers compare the sender’s IP to your SPF list — mismatches look like spoofing.

DMARC (Domain-based Message Authentication)

A policy telling receiving mail servers what to do when a message claims to be from your domain but fails SPF or DKIM. Even a permissive policy (v=DMARC1; p=none) helps because it generates reports on spoofing attempts.

Set up DKIM

With Postmark, Resend, MailerSend, or similar

When you verify your sending domain in your SMTP provider’s dashboard, they’ll give you DKIM records to add to your DNS. Add them, save, then mark verified in the provider’s dashboard.

With SendGrid

  1. Log in to SendGrid.
  2. Settings → Sender Authentication.
  3. Click Authenticate Your Domain and follow the prompts.
  4. Add the DKIM records they provide to your DNS, then verify.

With Google Workspace

  1. Log in to your Google Workspace Admin Console.
  2. Apps → Google Workspace → Gmail.
  3. Open Authenticate email.
  4. Generate DKIM and add it to your DNS.

Google’s full DKIM guide.

Set up SPF

Add a single TXT record to your domain’s DNS listing the services authorized to send for you. If you only use Google Workspace plus SendGrid:

v=spf1 include:_spf.google.com include:sendgrid.net ~all

Add include: entries for every additional service. References:

Set up DMARC

Easiest path: use a managed DMARC service that handles the DNS record and reporting for you. EasyDMARC has a free plan that walks you through it. They also surface spoof reports as a graph rather than the raw XML emails DMARC sends.

Doing it manually: add a DMARC TXT record at _dmarc.yourdomain.com. Start with a permissive policy:

v=DMARC1; p=none; rua=mailto:dmarc-reports@yourdomain.com

Once you confirm legitimate mail isn’t being flagged, tighten to p=quarantine or p=reject.

Reverse DNS (high-volume senders)

If you’re sending more than 5,000 emails per day, set up reverse DNS (PTR records). Most SMTP providers handle this automatically — for SendGrid, configure it in the Sender Authentication section. SendGrid’s reverse DNS guide.

Monitor spam rates

Sign up for Google Postmaster Tools and watch your spam rate. Keep it below 0.30%; brief spikes are fine, but sustained higher rates push you to spam folders systematically.

Common issues

  • DKIM record won’t validate — most often a copy-paste mistake. Re-paste the exact record value (no extra spaces) and check the record name matches what your provider gave you (e.g., s1._domainkey).
  • SPF says “too many DNS lookups” — SPF has a 10-lookup limit. If you’ve added many include: entries, consolidate or use a flattening service.
  • Emails still landing in spam after setting up everything — sender reputation takes time to warm. Avoid sending bursts of new emails to cold lists; gradually increase volume over 2-4 weeks.
  • I’m using Fileflare’s default sender, do I need any of this? No. Fileflare handles DKIM, SPF, DMARC, and reverse DNS on the default noreply@digital-downloads.com sender.

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