Whether you're new to cold email or just want a refresher, this guide walks you through the deliverability basics and shows how Instantly supports you along the way🚀
What is email deliverability?
In simple terms: deliverability is how likely your email is to land in someone's inbox instead of their spam folder.
Every time you send an email, providers like Gmail and Outlook decide how much they trust your account. They look at things like:
How trustworthy your email account is
How fast you're increasing how much you send
How clean your contact list is
Whether people open, reply to, or ignore your emails
Whether your account is set up correctly
The better your habits, the more of your emails land in the inbox.
The 7 things that matter most
1. Warm up your email accounts
A brand-new email account has no track record yet. If you send hundreds of cold emails on day one, providers get suspicious – even if everything else is set up right.
The fix: build trust slowly. Start small, then increase your sending over time. This is called warmup.
How to turn on warmup in Instantly
Go to the Email Accounts tab
Find the account you want to warm up
Click the flame icon next to it
Warmup starts automatically at the next 12:00 AM UTC, so don't worry if you don't see activity right away.
💡 Want to skip the wait?
If you want to start sending right away, we offer Pre-warmed accounts that are already warmed up and ready to use in the campaign on day one. Pre-warmed accounts include:
Google Workspace inboxes that are already warmed up
DNS records(MX, SPF, DKIM, and DMARC) already set up for you
Sold in batches of 5 accounts per domain
Ready-made domain and username (can't be customized)
2. Don't rely on one mailbox
Email providers expect sending activity to be distributed. Using multiple mailboxes helps protect your reputation and lets you scale your outreach more safely.
Instantly offers:
3. Start with a clean list
Even a perfectly set up email account can land in spam if you're emailing bad contacts. Avoid sending to:
Invalid email addresses
Old contact lists
Contacts you haven't verified
The cleaner your list, the better your deliverability.
You can verify email addresses right inside Instantly before you launch a campaign. Catching invalid or risky addresses early keeps your bounce rate low and protects your reputation.
Verification Cost: 0.25 Instantly Credits per lead
4. Watch your bounce rate
Your bounce rate shows how many emails failed to deliver.
We will automatically pause campaigns when the bounce rate exceeds 5% to protect your sender reputation and deliverability. This feature is enabled by default for all users
You can customize the bounce rate threshold that triggers a pause(Default is 5%) in Preferences.
Campaigns must send at least 200 emails before this check runs.
💡 Let the Deliverability AI Agent watch it for you
The Deliverability AI Agent checks your workspace, campaigns, and sending accounts around the clock – including your bounce rate. If it spots a problem, it flags it before it grows into something bigger.
Plan Requirement: Available to the Hyper Growth and above Email Outreach plans
5. Keep your first email simple
Your first email should read like one person writing to another – nothing fancy. We recommend:
Plain text
No links
No open tracking
Short, conversational writing
Tracking pixels and links can make an email look like a mass blast, which is more likely to get filtered.
💡 Make this automatic
You can set this as the default for every campaign:
Go to Settings → Advanced Deliverability
Turn on "Always send first email as text-only"
Save changes
6. Match email providers
Whenever you can, send:
Gmail to Gmail
Outlook to Outlook
This is called provider matching. Many customers see better inbox placement by keeping emails within the same provider.
Instantly does this automatically for you. You can enable Email Service Provider (ESP) Matching for all campaigns in the workspace by following the steps below:
Go to the Advanced Deliverability setting
Enable ESP Matching
Save changes
7. Remember: no tool can guarantee the inbox
You may come across platforms that claim they can guarantee inbox placement. That's not true – no email platform can honestly promise that.
Gmail, Outlook, and other providers make that call, not any sending tool.
What actually helps: following good habits consistently, and using the right tools to make that easier.
Quick deliverability checklist
Before launching your next campaign, make sure you've covered the basics:
Warmed up your email accounts (or bought Pre-warmed Accounts)
Sending from multiple mailboxes
Verified your contact list
Bounce rate below 2%
First email is plain text
No links in your first email
Open tracking turned off on the first email
Provider matching turned on where possible
How Instantly helps
Deliverability can sound technical, but it doesn't have to be. Instantly brings everything into one place, so you avoid common mistakes and keep your sender reputation strong.
If you're short on time – or simply don't want to manage every step of the outreach process yourself – you can use AI Sales Agent.
AI Sales Agent helps automate prospecting and outreach by finding qualified leads, personalizing emails, managing follow-ups, and booking meetings on your behalf.
It works alongside Instantly's deliverability features, so you can focus on having conversations with interested prospects instead of worrying about the technical setup or day-to-day campaign management.
Whether you're a solo founder, a small team without a dedicated GTM expert, or a growing sales organization, AI Sales Agent makes it easier to start generating pipeline while following the same deliverability best practices covered in this guide.
Final thought
Deliverability isn't about secret tricks or complicated settings. It's about building trust with email providers and consistently following good sending habits.
Instantly gives you the tools, automation, and support to make that process simple – so you can spend less time worrying about deliverability and more time starting conversations with your ideal customers.
Need help?
We're here to help you succeed.
Book a 1:1 demo for personalized guidance on setup, deliverability, and getting the most out of Instantly.
Chat with our Support team for quick help with troubleshooting, product questions, and best practices.
Whether you're just getting started or scaling your outreach, our team is ready to help.






