My app emails keep going to spam, how do I fix deliverability?

Spam-foldering usually comes from a mix of authentication, reputation, content, and sending behavior. Here’s a practical checklist to improve deliverability:

1) Set up email authentication

Make sure your domain is properly authenticated:

• SPF: authorizes which servers can send for your domain
• DKIM: signs messages so receivers know they weren’t altered
• DMARC: tells inbox providers how to handle failed SPF/DKIM and gives you reports

Also ensure:

• The From: domain matches your authenticated sending domain
• You’re not using a free mailbox (like gmail.com) as the From address for app mail

2) Use a reputable sending service

If you’re sending app emails from your own server or a cheap shared host, deliverability often suffers. Consider:

• Amazon SES
• Postmark
• SendGrid
• Mailgun
• SparkPost

These usually provide better IP reputation, bounce handling, and tooling.

3) Warm up your domain / IP

If this is a new domain or IP, don’t send large volumes immediately.

• Start with low volume
• Increase gradually over days/weeks
• Send first to your most engaged users

Sudden volume spikes look spammy.

4) Clean your recipient list

Poor list hygiene hurts reputation:

• Remove invalid addresses and hard bounces immediately
• Stop emailing users who never open/click
• Avoid purchased lists entirely
• Use double opt-in if possible

5) Improve message content

Spam filters are sensitive to:

• Overly salesy subject lines
• URL shorteners
• Lots of images and little text
• Too many links
• Spammy words like “FREE!!!”, “Act now”, etc.
• Mismatched display text and actual links

Tips:

• Keep a good text-to-image balance
• Include a plain-text part
• Make your “From” name recognizable
• Keep branding consistent
• Avoid attachments unless necessary

6) Make sure users want the emails

Engagement affects inbox placement:

• Send only requested mail
• Let users choose email categories/frequency
• Make unsubscribe easy
• Send relevant, expected messages

Transactional emails should be clearly transactional; marketing emails should be consent-based.

7) Check technical details

Verify:

• Correct reverse DNS (PTR) if using your own IP
• Valid HELO/EHLO name
• TLS enabled
• No broken links
• No malformed headers
• Proper MIME formatting

8) Monitor reputation and feedback

Use tools to see what inbox providers think:

• Google Postmaster Tools
• Microsoft SNDS
• DMARC aggregate reports
• Bounce/complaint logs from your provider

Watch:

• Spam complaint rate
• Hard bounce rate
• Open/click trends
• Blacklist status

9) Separate email types

Use different subdomains or streams for:

• Transactional: receipts, resets, alerts
• Marketing: newsletters, promotions

Example:

• mail.example.com for transactional
• news.example.com for marketing

This helps protect critical mail from marketing reputation issues.

10) Test deliverability

Send test messages to:

• Gmail
• Outlook/Hotmail
• Yahoo
• Apple Mail/iCloud

Use tools like:

• Mail-tester.com
• GlockApps
• Postmark spam tools

They can reveal authentication, content, and blacklist problems.

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Quick wins

If you want the fastest improvements:

1. Set up SPF, DKIM, DMARC
2. Send through a reputable provider like Postmark/SES
3. Lower volume and warm up gradually
4. Clean your list and remove bounces
5. Simplify content and avoid spammy wording

If you want, I can help you diagnose your setup step-by-step. If you paste:

• your sending domain,
• provider (SES/SendGrid/etc.),
• a sample message,
• and whether it’s transactional or marketing,

…I can give more specific fixes.