How to Show Full Email Headers in Apple Mail on Mac (2026)

Full email headers in Mac Mail are one menu away: pick the message, then choose View > Message > All Headers. Every header field appears above the message body. Choose View > Message > Default Headers to hide them again. For the complete, unformatted message, choose View > Message > Raw Source instead.

Headers are the part of an email nobody reads until something feels off: an invoice with new bank details, a "password reset" you never asked for, a reply that went to an address you didn't recognize. This guide covers the three ways to see headers in Mail on macOS 27 (All Headers, Raw Source and a saved .eml file), how to keep the fields you care about on screen all the time, what the important lines actually mean, and how to hand headers over to IT or Apple when a message looks like phishing.

How to show all email headers in Mac Mail

Apple Mail shows a short set of headers by default (From, To, Cc, Subject, Date). The All Headers command expands that to every field the message carries, such as Return-Path, Received, Message-ID and List-ID. These steps come from Apple's guide to showing detailed headers in Mail:

1. Open Mail and select the email in the message list.
2. In the menu bar, choose View > Message > All Headers.
3. Read the extra fields above the message body. Scroll the header area if it's long.
4. To go back to the short view, choose View > Message > Default Headers.

Mail prints the keyboard shortcut beside each command in the View menu. On a US keyboard, All Headers is Shift-Command-H and Raw Source is Option-Command-U. Apple's shortcut list for Mail doesn't include either one, so if a shortcut doesn't respond on your keyboard layout, use the menu.

If you check headers often, there's also an All Headers button you can add to the toolbar: Control-click an empty spot in the toolbar, choose Customize Toolbar, and drag it in, as iDownloadBlog describes.

How to view the raw source of an email in Mail

Raw Source opens the whole message exactly as it arrived: every header, then the body as plain text or HTML, with attachments as encoded blocks. It's the view to use when you need to copy headers for someone else or search for one specific line. Select the message and choose View > Message > Raw Source; a separate window opens.

The window is long and hard to scan, so search it. Press Command-F in the Raw Source window and type the field you want, such as `Return-Path` or `Authentication-Results`, a tip that also turns up in this Apple Support Community thread. To copy the headers, select from the first line down to the blank line where the body starts, then press Command-C.

Save an email with its headers as a file

To keep a complete copy, headers included, save it as an .eml file. Apple's guide to saving emails as files gives two ways:

• Select the message, choose File > Save As, and pick Raw Message Source as the format. Mail saves a single message as an .eml file.
• Drag the message from the list to your desktop. If you drag a whole conversation, each message becomes its own .eml file.

The other formats, Rich Text Format, Plain Text and File > Export as PDF, save what you see on screen rather than the full source, so use Raw Message Source when the headers are the point. When my bank's fraud team asked for a suspicious email "with full headers," the .eml file was what they wanted. It opens in Mail on any Mac and in most other email apps.

How to always show certain headers in Apple Mail

Apple Mail can add chosen header fields to the default view, so you see them on every message without switching to All Headers. Apple's Viewing settings guide describes the option:

1. Choose Mail > Settings and click Viewing.
2. Open the Show message headers menu and choose Custom.
3. Click Add and type the name of a header field, such as `Reply-To` or `Return-Path`.
4. Repeat for each field you want, then close the window.

Set the menu back to Default to undo it. Keep the custom list short. Two or three fields is useful; ten turns every message into a wall of text.

I keep Reply-To in my custom list. Most of the time it's empty or matches the sender. When it doesn't, I see it before I hit Reply instead of after, which is the moment it matters.

What the important email headers mean

Email headers are labeled lines, each a field name, a colon and a value. Most are defined in RFC 5322, the internet standard for message format. You only need a handful to answer the usual questions: who sent this, where did it travel, and did it pass authentication?

Reading Received lines from the bottom up

Every mail server that handles a message stamps a new Received line above the existing ones; the SMTP standard, RFC 5321, requires servers to prepend these lines and never reorder them. So the bottom Received line is the first server that touched the email, and the top one is your provider's server, just before it reached you. The final delivery server also adds the Return-Path line.

Each Received line ends with a timestamp. When a colleague's message showed up hours after they said they'd sent it, the Received lines settled it: the timestamps were close together until one hop inside their company's mail system, where it had waited before moving on. If the times are hard to compare across time zones, paste the header into Google's free Messageheader tool, which lines up every hop and points to where a delay happened.

SPF, DKIM and DMARC in the Authentication-Results line

The Authentication-Results header records the checks your provider ran when the message arrived, written as method=result pairs such as `spf=pass` or `dkim=fail`, per RFC 8601. In short:

• SPF checks whether the sending server is allowed to send for the domain in the envelope (the Return-Path).
• DKIM checks a signature the sending domain added, proving the message wasn't altered on the way.
• DMARC passes when SPF or DKIM passes for a domain that matches the From address, per RFC 7489. It's the one that ties the checks to the name you see.

Trust the Authentication-Results line your own provider added, which sits near the top. RFC 8601 warns that the field has no protection of its own, so a sender can paste a fake one lower down. If you see more than one, the top one is from the server closest to you.

How to tell if an email is fake from its headers

Headers can't prove an email is safe, but they often show when one isn't. Open the message with View > Message > All Headers (or Raw Source) and work down this list:

1. Compare From and Reply-To. A bank, a supplier or your own CEO rarely asks you to reply to a different domain.
2. Check Return-Path. Marketing platforms legitimately use their own domains here, so a mismatch alone isn't proof. A random free-mail address on a "bank" email is.
3. Read Authentication-Results. `dmarc=fail` on mail claiming to be from a big brand is a strong sign of spoofing.
4. Look at the bottom Received line. It shows where the message started. A server that has nothing to do with the company is worth questioning.
5. Check the DKIM d= domain. If the signing domain has no link to the sender, the signature only proves who sent it, not who they claim to be.

The invoice that taught me this habit looked perfect: right logo, right name, right signature. The only odd thing was a line asking me to update the bank details. Reply-To pointed to a domain one letter off from the supplier's, and DMARC had failed. I called the supplier on the number I already had, and they hadn't sent it.

Mail that's merely unwanted, rather than dangerous, is a job for the junk filter; the walkthrough of Mac Mail's junk settings covers training it and blocking senders.

How to send email headers to IT or report phishing

To pass a suspicious email on with its headers intact, forward it as an attachment. A normal forward creates a new message with your headers, not the original sender's. In Mail, select the message and choose Message > Forward As Attachment. Apple's phishing guide recommends exactly this when you report a fake Apple email to reportphishing@apple.com, so the header information goes with it.

Other options, depending on what the person asking needs:

• An .eml file: File > Save As > Raw Message Source, then attach the file to a ticket or email.
• Pasted text: copy the header section from View > Message > Raw Source and paste it into the ticket. Some help desks prefer this because they can read it without opening a file.
• Your provider's report button: for a Gmail or other hosted account, also report it in that provider's own app or webmail.

Before sending headers anywhere outside your company, remember they include your own address, your provider's server names and sometimes internal hostnames. That's fine for your IT team or Apple's phishing address; it's more than a random forum needs.

Full headers on iPhone, iPad and iCloud.com

Apple doesn't document a way to show full headers in the Mail app on iPhone or iPad. When I need headers away from my Mac, I use the web instead:

• iCloud Mail on the web: at icloud.com/mail, select the email, open the menu in the message header and choose Show All Headers; Show Default Headers switches back. Apple's iCloud guide says the full view adds the return and delivery paths, the Reply-To field and the content type, and works the same way on iPad.
• Gmail in a browser: open the email, choose More (the three dots beside Reply), then Show original, per Google's header help page. Copy to clipboard grabs the whole header.

For any other account, the provider's webmail usually has a similar "show original" or "view source" option. Back on the Mac, Apple Mail shows the same headers no matter which account the message came from.

When the header options don't do what you expect

A few things trip up the View > Message commands in Mail for macOS:

• You're in a new message window. In a compose window, the View menu controls address fields instead, such as Bcc (Option-Command-B) and Reply-To (Option-Command-R) in Apple's shortcut list. Click back into the main Mail window and select a received message.
• You can't find who was Bcc'd. Headers usually won't tell you. RFC 5322 lets mail software remove the Bcc line from the copies other people receive, which is the point of Bcc.
• Extra fields show on every message. That's the Custom option in Mail > Settings > Viewing at work. Set Show message headers back to Default if you no longer want them.
• A forwarded copy has no useful headers. A normal forward is a new message with new headers. Ask the sender to use Forward As Attachment or send an .eml file instead.

If you'd rather drive all this from the keyboard, our list of Apple Mail keyboard shortcuts also shows how to add your own shortcut to a Mail menu command in System Settings. And if you're still finding your way around Mail in general, the Apple Mail guide covers accounts and settings from the start.