EML Editor Online

Open an EML or MSG, edit its message fields and save a new EML. Preview the copy before downloading; your original file stays unchanged.

How it works

Header fields: 4000 characters each. Files and encoded EML up to 25 MB.

Preview

Rebuilt copy

Enter a message or open a file, then update the preview.

Email views File format

A new MIME copy is rebuilt. Original routing headers and signatures are not preserved.

How to edit an EML file

This editor works with the decoded message, not the raw source layout. Change common headers, plain text, optional HTML and attachments. The downloaded copy is rebuilt as MIME with a new Message-ID; delivery records, custom headers and old signatures are not copied.

Open your email or try the fictional sample.
Edit the fields and attachments, then select Update preview.
Choose EML to save a new message, or another format for a readable copy.

What the rebuilt EML keeps

Sender, To, Cc, Bcc, subject, a valid date, supported bodies and decoded attachments are carried into a new message. Unicode names and attachment filenames are encoded for MIME. Inline images retain supported content IDs.

This is a basic message editor. It does not preserve every Outlook property, the original MIME tree, delivery history or digital signatures. Keep the source file if those records matter. HTML previews are sanitized; EML downloads retain the HTML you entered.

Edit a sample without changing the original

Open the fictional sample. Change the subject and replace the arrival time in both body fields as shown below. Update the preview and check the Email and Plain text views.

The edited EML below was rebuilt with those changes. Reopen it in this editor or your mail application to compare the subject, both bodies and attachment. Keep the original separately; the copy has new metadata.

Before: original subject and body excerpts

Subject: Your studio visit is confirmed
text/plain: 10:00 AM – 12:00 PM
text/html: 10:00 AM – 12:00 PM

Decoded excerpts from the fictional input EML. The arrival time is present in both plain text and HTML.

After: edited subject and body excerpts

Subject: Your studio visit starts at 10:30
text/plain: 10:30 AM – 12:00 PM
text/html: 10:30 AM – 12:00 PM

The actual edited EML has 10:30 AM in both bodies. The unchanged visit-details.txt attachment still says 10:00 AM; review attachments separately.

Why an edit may not appear in the preview

A formatted preview normally shows the HTML alternative. Changing only plain text will not rewrite that HTML. Update both fields when the same correction should appear in either view, then update the preview again.

If the rebuilt file exceeds the size limit, remove large attachments. MIME encoding adds size to binary files. The sanitized preview also differs from the EML download: the download retains the HTML source you entered, so previewing does not clean that source.

EML editor questions

Can I edit the original file in place?

No. The browser creates a separate download. It does not overwrite the file you opened.

Will a digital signature remain valid?

The rebuilt copy omits existing authentication and signature headers. Editing a message does not establish its authenticity.

Does my data leave my device?

Your selected files and pasted text are processed in your browser, without being uploaded to EMLKit. Remove the input or leave the page to clear the current workspace. Ordinary page requests still reach the site host. Read about file handling.