Why do my emails end up in other people's junk folders?

Filtering decisions are made by the receiving provider using signals you cannot see. You cannot control the outcome, but a small number of habits account for most avoidable filtering.

Step by step

1. Establish whether it is one recipient or all of them.One recipient is their filter, and easily fixed at their end. Everyone is a signal about your address or your message.
2. Ask the recipient to whitelist you.Marking the message as not junk and adding the address to their contacts is the strongest signal there is to their provider, and it usually holds permanently.
3. Check the sending address is what you think.Sending from an unfamiliar address, or with a display name that does not match the address, raises suspicion. A mismatch between name and address is a common phishing pattern.
4. Avoid bulk sending from a personal account.A personal mailbox sending to forty recipients at once looks like exactly what filters are built to catch. Use a mailing service for anything genuinely bulk, or send in small batches.
5. Look at the content.Multiple links, shortened links, a large image with almost no text, all-capital subject lines, and words associated with money or urgency all push messages towards junk.
6. Be careful with attachments.Zip files and anything executable are aggressively filtered. Sending a link to a cloud file avoids it and is more reliable for anything large.
7. Do not send from an address that is not yours.Configuring a mail program to send with someone else's address, or a work address from a personal account, commonly fails modern authentication checks and lands in junk.
8. Check your own domain if you have one.A custom domain needs its sending records configured properly. Without them, mail from your own domain is widely filtered. Your provider publishes what to set, and it is a one-off task.

Tips

• Replies to an existing conversation are filtered far less often than new messages. If something important keeps failing, ask them to email you first.
• For anything genuinely important — a job application, a legal deadline — follow up by phone rather than assuming it arrived.
• Forwarding a chain with dozens of previous recipients visible is a strong junk signal as well as poor practice.

Common mistakes

• Sending a newsletter from a personal mailbox — Personal accounts have sending limits and no reputation for bulk mail. It gets filtered, and repeated attempts can restrict the account itself.
• Adding lots of links to make a message helpful — Link count is a strong filtering signal. One link and a sentence explaining it performs far better than five.

If it doesn't work

Questions people ask