Email Deliverability

Reputation and Landing in the Inbox.


Email Sending Reputation is assigned to you by Inbox Service Providers and is at the core of Email Deliverability. Your reputation will determine Inbox placement, the amount of mail Inbox Providers will accept from you, and if your emails will be outright blocked by Inbox Providers.

Your Sending Reputation works like a credit score that can go up or down based on the historical performance of your mail.

Your reputation may be negatively affected if you receive Spam Complaints from recipients, you have a high bounce rate, or if you send to spam traps.

Your reputation may be positively affected if you have a high engagement with your emails like opens, clicks or replies.

Where to see your Reputation in OneSignal (click to expand)

You can view a full list of your users' email addresses that bounced or complained and the rate at which these events occurred within your OneSignal dashboard Settings > Email > Email Reputation.

App Settings Dashboard

App Settings Dashboard

Email Reputation

The rates in which your users bounce or report your emails as spam over a 24-hour, 7-day, and 30-day period. Rates are calculated across all emails sent in the current app.

Email Reputation Dashboard

Email Reputation Dashboard

If your bounce and spam report rates are too high, it will affect your domain and IP reputation which reduces deliverability and potentially violates our Acceptable Use Policy & Code of Conduct.

You should aim for as little bounces or complaints as possible. A bounce rate of 5% and/or a complaint rate of 0.5% is considered high and would hurt the reputation of a domain, likely to be flagged by the Inbox service provider.

See How to Lower Email Bounce and Complaint rates for more details.

Inbox Service Providers

ISPs like Gmail, Yahoo and Microsoft control if, when and where your emails get delivered. At the end of the day, Inbox Providers are trying to create the best and safest inbox experience for their customers, the recipients. Its important we play by their rules so that your emails get delivered to the right place at the right time.

Because there are multiple Inbox Service Providers with different ways of calculating reputation, your reputation will vary with each ISP.

Warming Up

Reputation also dictates the volume that Inbox Providers are willing to accept from you. If you attempt to send a high volume from a subdomain that has never sent or has not sent high volumes recently, then it is likely to get rejected and treated poorly.

When starting to send email on a new platform, from a new subdomain or suddenly increasing your volumes from the first time in a while, you will likely need to go through a "Warm Up" process to ensure the best email deliverability.

Check out our Auto Warm Up Feature

Consent and Opt-ins

Email is a consent based messaging channel. All your recipients should give you explicit consent to be emailed. Sending to non-opted in or unsubscribed recipients will often result in spam complaints. Consent can be obtained verbally, through a business card exchange or through a contact form on your website.

To really follow best practice and maintain good reputation, you may wish to implement a "Confirmed" or "Double" Opt-in.

Learn more about Setting Up a Double Opt-In with OneSignal


Unsubscribes occur when recipients choose to opt-out of receiving further email communications from a sender. This action is typically initiated by clicking on an "unsubscribe" link included in the email message. Unsubscribes are a fundamental aspect of email marketing compliance and recipient consent.

When a recipient unsubscribes, it indicates a lack of interest or preference to disengage from future email interactions. As such, honoring unsubscribe requests promptly is essential for maintaining sender reputation, compliance with anti-spam regulations like the CAN-SPAM Act, and fostering positive recipient relationships.

Learn more about Unsubscribe Links and Email Subscriptions

Spam Complaints

Complaints or "Spam Reports" arise when a recipient reports or marks an email as spam in their inbox.

App Settings Dashboard

Yahoo Report Spam Button

Common reasons for complaints include irrelevant content, excessive frequency, or emailing recipients that did not opt-in.

To maintain a positive sending reputation and avoid deliverability issues, it is important to minimize complaint rates. Regularly analyze feedback, adjust content strategies, and provide easy opt-out options to ensure a satisfactory email experience for recipients.

Learn How to Lower Spam Complaint Rates


A bounce occurs when an email can not be delivered to a target email address. The Inbox Provider will typically provide a "bounce message" that gives a reason for non-delivery.

Bounces generally occur because you are sending to email addresses that do not exist or are spelled incorrectly.

Bounce Message in Suppression List

Bounce Message in Suppression List

Bounce messages can be seen in your Audience Activity and in your Suppression List

Learn more about How to Lower Email Bounce and Complaint Rates


Failures may occur if your domain is misaligned, recipient inboxes are full, or if you are being blocked by Inbox Providers for having a poor reputation.

"Too Old" deferral messages from Gmail for Poor Reputation

"Too Old" deferral messages from Gmail for Poor Reputation

Failures may be temporary and are often retired by our servers for a duration.

Failures can be seen in your Audience Activity on your Email Message Reports and do not get added to your Suppression List.

Suppression List

The suppression list prevents you from sending to email addresses that have bounced as invalid and to recipients who have reported your mail as spam.

Where to see your Suppression List in OneSignal (click to expand)

You can view a full list of your users' email addresses that bounced or complained within your OneSignal dashboard Settings > Email > Suppression List


Track which email addresses bounced and reported emails as spam. These addresses will be removed from further email sends.

You can add emails manually with the Add Email button and remove emails from the list with the trash can icon.

Suppression List(Bounces, Reported as Spam)

Suppression List (Bounces, Reported as Spam)


Blocklists are lists of IP addresses or domains that have been identified as sources of spam or malicious activity. Inbox Providers have internal blocklists and often consult 3d party blocklists to filter out unwanted emails. If your IP address or domain is on a blocklist, your emails may be automatically rejected or sent to the spam folder.

Spam Traps

Spam traps are email addresses that are not actively used by real individuals but are set up by ISPs or anti-spam organizations to identify spammers. If you send emails to spam traps, it indicates poor list hygiene or acquisition practices and can severely damage your sending reputation.

Learn more about Spam Traps and How to Avoid Them


Opens refer to the number of times recipients open your email messages. Tracking email opens provides insights into the effectiveness of your subject lines, targeting and sender identity. High open rates indicate good inbox placement and engagement from recipients.


Clicks represent the number of times recipients interact with links within your email messages. Tracking clicks allows you to measure the engagement and effectiveness of your email content and call-to-action (CTA). High click-through rates indicate that your emails are resonating with recipients and driving desired actions. Since recipients must open emails before being able to click a link, clicks are a very strong indicator of engagement.

Inbox Placement

Inbox placement refers to where your email messages are delivered within recipients' email inboxes. Proper inbox placement ensures that your emails are seen by recipients in the correct context and increases the likelihood of engagement. Inbox placement can be categorized into different sections of the inbox, such as Primary, Promotions, or Spam folders.

Gmail Inbox Tabs

Gmail Inbox Tabs


The Primary Tab typically where important and personal communications are received. Achieving primary inbox placement indicates good sender reputation and email relevance, increasing the likelihood of recipients engaging with your messages.


Promotions refers to emails that are delivered to a separate tab or folder within recipients' inboxes, specifically designated for promotional or marketing emails. While still visible to recipients, emails in the Promotions tab may receive less immediate attention compared to those in the Primary inbox. Inbox Providers often use algorithms to determine which emails are categorized as promotions based on sender reputation and email content.

Emails Landing In Promotions (click to expand)

Emails landing in the Promotions Tab is not an indicator of bad reputation and is not a bad place for marketing emails to land. If an email is inherently promotional or marketing related, then it may actually perform better in the context of the promotions tab.

The promotions tab has been found to reduce spam complaints and increase engagement as it helps emails meet the expectations of recipients. When a recipient visits their promotions tab, they are in a different mindset and are more receptive to looking for deals or shopping.

Emails often land in promotions due to automated filters categorizing them based on content and previous recipient behavior. To land more in the primary tab, avoid using excessive promotional language, personalize content, and encourage recipients to move emails to their primary tab.


Spam inbox placement refers to emails that are filtered by Inbox Providers and delivered to recipients' spam or junk folders. Emails categorized as spam may contain suspicious or unwanted content, trigger spam filters, or have low sender reputation.

Emails Landing In Spam (click to expand)

Emails landing in the Spam Folder is usually an indicator that you currently have a poor reputation. The first thing you should check is for anything that would have negatively affected your reputation. Has your complaint or bounce rate been higher than it should be? According to Google, "senders should keep their spam rate below 0.1%".

Learn more about How to Lower Email Bounce and Complaint RatesIf placement in the spam folder does not seem reputation related, double check that your DMARC is properly aligned. About My Email is a great testing tool to check for alignment.

See why DMARC is required by Google and Yahoo.