Everything I learned about deliverability after landing in spam for 6 months

When I started doing cold outreach for my SaaS startup, watching every email go straight to spam sucked. Open rates were under 5%, reply rates were zero, and Google basically blacklisted my domain.

So I started testing things to figure out what actually works vs stuff that doesn’t matter anymore. Here’s what I found, ranked from least to most impactful:

1. Remove "spam trigger words"

Everyone says "never use words like FREE or DISCOUNT." It made literally zero difference for me. Modern spam filters care way more about domain reputation than individual words. Don't waste time obsessing over this.

1. Add a physical address

Necessary for legal reasons, but did it help deliverability? Nope. Maybe a 1-2% bump, but it won't get you out of spam.

1. Ditch images and links

Cold outreach should look like a normal email from a real person. Cutting out images and keeping links to the absolute minimum (or zero) made a solid difference for inbox placement. Also remove custom HTML signatures with logos and 5 social links. Plain text is king.

1. Set up SPF, DKIM and DMARC

The technical baseline. If those aren't set up properly in your DNS settings, Google and Outlook will flag you almost immediately. It’s annoying to set up, but non-negotiable.

1. Warm up secondary domains

Rule #1 of cold outreach: never burn your primary domain. Get a separate domain, set up proper warmup for at least two weeks, and ramp up sending slowly. Starting with 50 cold blasts a day on a fresh domain is instant suicide.

1. Get actual replies

The absolute biggest factor. Spam filters monitor how people interact with your emails. If people reply, ISPs assume you're legit. I completely rewrote my copy to be super short, casual, and focused on starting a conversation instead of pitching hard. Once reply rates went up, everything else got much easier.

TL;DR:

Set up your DNS records, use secondary domains, keep it plain text, and write quick emails that actually make people want to hit reply.

Also, if your main domain is already burned, just cut your losses, buy a new one, and start fresh.

Anyone else dealt with this in 2026? What actually worked for you?