Email Deliverability: Gmail, Yahoo and Outlook Sender Rules
Since 2024 the biggest inbox providers reject or filter email from senders who skip authentication or ignore unsubscribes. This guide explains each rule, the dates and the simple checks that keep your email out of spam.
To reach Gmail, Yahoo and Outlook inboxes, send from your own domain with SPF and DKIM passing and a DMARC record of at least p=none, aligned with your From address. Bulk senders must offer one-click unsubscribe, honour it within two days and keep spam complaints below 0.3%, ideally under 0.1%.
Authenticate your domain
SPF, DKIM and DMARC, aligned with the domain in your From address.
One-click unsubscribe
Required by Gmail and Yahoo for marketing email from bulk senders.
Spam rate under 0.3%
Aim below 0.1%. Above 0.3%, Gmail limits what help you can get.
Outlook rejects failures
Since 5 May 2025, non-compliant bulk mail gets a 550 5.7.515 rejection.
What changed, and when
Google and Yahoo introduced new sender requirements from February 2024. Every sender must authenticate its mail and keep spam complaints low, and bulk senders must also publish DMARC and offer one-click unsubscribe. Gmail stepped up enforcement from November 2025, with temporary and permanent rejections for mail that does not comply.
Microsoft followed for Outlook.com, Hotmail and Live addresses. From 5 May 2025, domains sending more than 5,000 emails a day must pass SPF and DKIM and publish DMARC. Mail that fails is rejected with the error 550 5.7.515.
Are you a bulk sender?
Google calls you a bulk sender if you send close to 5,000 or more messages to personal Gmail accounts in 24 hours. Mail from all subdomains of your main domain counts together, and once you reach the mark the status is permanent. Microsoft uses more than 5,000 emails a day. Yahoo publishes no number.
A shop with 20,000 customers that sends one festival email has crossed the line. Treat every rule below as applying to you, even if most of your email is receipts. The rules are also simply good practice: authenticated, wanted email with an easy way out is what every inbox provider rewards, whatever your volume.
SPF, DKIM and DMARC in plain words
SPF is a DNS record that lists which servers may send email for your domain. DKIM adds a digital signature to each email, checked against a public key in your DNS. DMARC tells inboxes what to do when SPF and DKIM fail, and asks for reports. Alignment means the domain in your From address matches the domain that passed SPF or DKIM.
Bulk senders need all three, with DMARC set to at least p=none. Start with p=none, read the reports for a few weeks to find every service that sends as your domain, then move to quarantine or reject. All senders also need valid reverse DNS and TLS, which your email provider's servers handle.
Unsubscribe and spam complaints
Marketing email from bulk senders must support one-click unsubscribe under the RFC 8058 standard, through the List-Unsubscribe and List-Unsubscribe-Post headers, and show a clear unsubscribe link in the body. Yahoo asks senders to honour unsubscribes within 2 days, and Google recommends 48 hours.
Keep your spam complaint rate in Google Postmaster Tools below 0.1%, and never let it reach 0.3%. Since June 2024, bulk senders above 0.3% cannot get help from Google to fix delivery problems. The quickest way to lower complaints is to email only people who opted in, and to make unsubscribing easier than clicking Report spam.
A checklist for Indian businesses
Run through this list before your next campaign.
- Send from your own domain, never from a free Gmail or Yahoo address
- Publish SPF and DKIM for every service that sends as your domain, including your CRM and helpdesk
- Add a DMARC record, start with p=none and read the reports
- Keep receipts and marketing on separate subdomains, such as mail.yourbrand.in and news.yourbrand.in
- Use one-click unsubscribe and remove unsubscribed people within 2 days
- Remove addresses that hard-bounce and never send to bought lists
- Check Google Postmaster Tools every week once you send in bulk
How our email service handles these rules
Our platform will not send from a domain until it is verified, and it checks SPF, DKIM and DMARC before sending and every day after that. Free-mail addresses cannot be used as the sender. Marketing emails get one-click unsubscribe headers automatically. Hard bounces, complaints and unsubscribes are suppressed, and an account is paused automatically if bounces or complaints rise past safe limits, before the problem reaches your domain's reputation.
Fix it in four steps
Audit your DNS
List every service that sends email as your domain and check its SPF and DKIM.
Publish DMARC
Add a p=none record with a reporting address and review the reports weekly.
Fix unsubscribes
Turn on one-click unsubscribe for marketing and act on requests within 2 days.
Watch complaints
Set up Google Postmaster Tools and keep the spam rate under 0.1%.
Frequently asked questions
Why are my emails going to spam in Gmail?
The most common reasons are missing or failing SPF, DKIM or DMARC, sending from a free email address, a high spam complaint rate, or mailing old lists with many dead addresses. Check your domain's DNS records, look at Google Postmaster Tools for your spam rate, and remove addresses that bounce or never open.
What are Gmail's bulk sender requirements?
Senders of about 5,000 or more emails a day to personal Gmail accounts must use SPF and DKIM, publish DMARC of at least p=none, align the From domain, support one-click unsubscribe with a visible link, and keep spam complaints below 0.3%. All senders need SPF or DKIM, valid reverse DNS and TLS.
What does error 550 5.7.515 mean?
It is Outlook.com's rejection for high-volume senders whose domain does not meet its authentication rules. Since 5 May 2025, domains sending more than 5,000 emails a day to Outlook, Hotmail and Live addresses must pass SPF and DKIM and publish DMARC aligned with one of them. Fix the records and resend.
Is DMARC p=none enough?
It meets Gmail, Yahoo and Outlook's minimum for bulk senders. But p=none only monitors. Once DMARC reports show that all your genuine email passes, move to p=quarantine and then p=reject, which stops others from sending email that pretends to come from your domain.
Do transactional emails need an unsubscribe link?
The one-click rule applies to marketing and subscribed email, not to receipts, password resets or account alerts. Keep transactional email separate from promotions, ideally on its own subdomain, so a complaint about a campaign does not affect delivery of invoices and login codes.
How quickly must I process unsubscribes?
Yahoo asks bulk senders to honour unsubscribes within 2 days, and Google recommends doing it within 48 hours. With one-click unsubscribe, the request reaches your email service at once, so suppress the address immediately rather than in a weekly batch.
Want email that reaches the inbox?
We verify your domain, set up unsubscribe and suppression, and send your transactional and bulk email from one account.