Avoiding the spam folder
There is no single trick that keeps mail out of the spam folder. Mailbox providers weigh many signals, but they cluster into three levers you control: who you are (authentication), what you send (content), and who you send to (list quality). Get all three right and inbox placement largely takes care of itself; neglect any one and the other two can't fully compensate.
Lever 1: Prove who you are
Providers junk mail they can't attribute to a real sender. Authentication is how your domain vouches for your messages: when your sending domain is verified with Bird, your mail is signed in your domain's name (DKIM), bounces flow back through an address aligned with your domain (which makes SPF pass and align), and your DMARC policy tells receivers the checks are in force. Recipients see your mail come from your domain, and providers can verify it really did.
The Bird action: verify your sending domain by publishing the DNS records from the domain's detail page. That single setup step covers DKIM, SPF alignment, and DMARC — the walkthrough is in the sending domains guide. It's also the core of the Gmail and Yahoo bulk-sender requirements, so it's not optional for any serious sender.
Lever 2: Send mail that looks legitimate
Content filters have moved well beyond keyword lists, but the basics still matter:
- Write honest subject lines. ALL CAPS, stacked exclamation marks, and "FREE!!!" framing are classic spam markers — and even when they get through, they train recipients to complain.
- Balance text and images. A message that is one giant image with no real text is a long-standing spam pattern. Include genuine text content, and make sure the message still makes sense with images turned off.
- Include a real, working unsubscribe link in every marketing message. Counterintuitively, an easy way out keeps you out of the spam folder: recipients who can't find the unsubscribe link click "mark as spam" instead, and complaints damage your reputation far more than unsubscribes do.
- Match what people signed up for. A sudden pivot in topic, frequency, or tone drives complaints even from genuinely opted-in recipients.
Lever 3: Send to people who want it
Providers watch how recipients react. Mail that gets opened and clicked builds your reputation; mail that bounces or gets reported tears it down. This lever is list quality:
- Send only to people who opted in, and remove the chronically unengaged — the full routine is in list hygiene.
- Keep bounce and complaint rates low and watch them on the Metrics page; the thresholds and what to do when they climb are in sender reputation monitoring.
- If your domain or volume is new, ramp up gradually rather than blasting at full volume from day one — see warming best practices.
When mail still lands in spam
If authenticated, well-formed mail to an opted-in list still hits the spam folder, the cause is almost always reputation history: a past spike in complaints or bounces, a cold domain, or a sudden volume jump. Check your rates on the Metrics page, slow down, concentrate on your most engaged recipients, and let the good signals accumulate — reputation recovers the same way it was built.
Related pages
- Gmail & Yahoo sender requirements — the formal rules large providers enforce for bulk senders
- Warming best practices — ramping new domains and IPs safely
- List hygiene — keeping bounces and complaints down at the source
- Sending domains — the developer guide to domain verification