Your sending reputation dictates whether your emails are seen by recipients. Follow this list of best practices to build and maintain a healthy sending reputation.
Sending emails to people who have not provided clear permission to be emailed often leads to emails being reported as spam, which actively harms your sending reputaiton.
Collecting the email as part of your sign up process or account creation is not enough. Consent needs to be explicitly given.
Opt-in Check Box
At minimum, include a checkbox asking for permission to send emails.
A confirmed or double opt-in process requires the recipient to confirm their interest by clicking a link in a confirmation email. This method:
Learn how to create a Confirmed Opt-in Journey.
Create an `initial_opt_in` tag
Add an initial_opt_in
tag with a value of true
for newly added or imported email subscriptions.
Create an Initial Opt-in segment
Create a segment called Initial Opt-in
using the initial_opt_in
tag.
Initial Opt-in Segment
Create a Confirmed Opt-in email template
Create an email template with a single “Confirm” button or link.
Create a Confirmed Opt-in Journey
Build a Journey that starts with the Initial Opt-in segment and immediately sends the confirmation email.
Confirmed Opt-in Journey Send
Add a Wait Node and Yes/No Branch
Add a 15-minute Wait node followed by a Yes/No branch to check if the confirmation link was clicked.
Wait Node and Yes/No Branch
Tag users who confirm
Tag users who clicked the confirmation link with confirmed_opt_in = true
.
Confirmed_opt_in Tag in Journey
Add additional follow-ups
Add Wait nodes and Yes/No branches to retry confirmation over several days.
Check for Confirmed Opt-in at Intervals
confirmed_opt_in
tag that you can use to create segments.Let users choose what types of emails they want—Newsletters, Rewards, Deals, Product updates, etc.
Email preference center
Make it easy for users to adjust these preferences anytime via an email preference center.
Unchecked spam reports can quickly destroy your sending reputation. Monitor them closely—more often than open or click rates.
You can view Spam Reports in the Audience Activity section of each message and in your Suppression List.
Consider why users might report your emails as spam:
Gmail is the largest inbox provider. If you’re seeing issues with Gmail, you’re likely having issues elsewhere too.
Google Postmaster Tools gives insights like domain reputation and spam rates from Gmail users.
Gmail does not provide per-user spam reports. Only aggregate spam rate data is available through Google Postmaster Tools.
Google Postmaster Tools
Learn how to set up Google Postmaster Tools.
Inbox providers reward high engagement. Recipients who open and click are more likely to receive future emails.
Email Opened Yes/No Branch
Low open rates indicate poor engagement and hurt your reputation.
Implement a sunset policy to remove users who haven’t opened or clicked emails in 2–3 months (depending on your send frequency).
Sending too many emails increases the risk of unsubscribes and spam complaints.
Evaluate frequency from the recipient’s perspective. Daily emails may be too much.
What NOT To Do
Every email should provide real value—insights, tips, solutions, or relevant updates.
A discount code alone does not equal value.
Your audience expects specific content types. Make sure you’re meeting those expectations.
Email is a conversation channel—not a billboard. Use it to build trust and invite responses.
Replies actually help your sending reputation.
Use a valid reply-to address. Avoid “no-reply” emails.
Inbox providers may block high-volume email sends from domains with no sending history.
If you’re sending large volumes—especially from a new domain or provider—gradually increase volume to build trust.
Learn more about Warm Up and how to use OneSignal’s Auto Warm Up.
High bounce rates hurt your reputation and indicate poor list hygiene.
Use Confirmed Opt-in to prevent invalid emails.
Before importing, clean your list by removing:
@gnail.com
, @yagoo.com
someone@.com
If migrating from another platform, use its Suppression List to avoid importing known bad addresses. You can also delete users or upload a Suppression List.
Validation tools can help detect invalid or risky addresses before import:
After validation, follow our import guide to upload clean, verified lists.