Generating URLs to a Gmail compose window
This post is over three years old. Some of it may no longer reflect current tooling or my current view.
I wanted to send out a small batch of follow-up emails for workshop attendees today, and I realized that since I have their emails in a database table I might be able to semi-automate the process.
I guessed that Gmail might have a way to generate a querystring URL to the compose interface such that the to/subject/body fields were filled out for me.
I ran prompts through ChatGPT, Claude and Google Gemini - in my experience LLMs often know about undocumented URL patterns like this.
The answer I got back turned out to work, but was out-of-date (it redirected to something different). Here’s what I figured out as the current correct format:
https://mail.google.com/mail/u/0/?to=recipient@example.com&cc=one@example.com,two@example.com&bcc=bcc@example.com&su=Email+Subject&body=Hello+There&tf=cm
Or more clearly formatted:
https://mail.google.com/mail/u/0/
?to=recipient@example.com
&cc=one@example.com,two@example.com
&bcc=bcc@example.com
&su=Email+Subject
&body=Hello+There
&tf=cm
The tf=cm parameter at the end is the one that navigates to a compose window.
The query string parameters are:
to- the recipients - can be comma separatedcc- CCs - can also be comma separatedbcc- BCCs - can also be comma separatedsu- the email subjectbody- the initial email body
What this gets you#
Tip about the /u/0/ bit#
Tip from Corentin Smith:
You can replace the
/u/0/with/u/youremail@gmail.com/, it will redirect you to the correct account
It doesn’t work on Mobile Web#
Frustratingly, attempting to click one of these links in Mobile Safari takes you to the Gmail inbox but does not open a compose window. I don’t know if there’s a workaround for that.
The answer from Gemini#
My prompt was:
I would like to build an application that helps me send out emails by constructing URLs to the Gmail interface in the way that will pre-fill the to and cc and subject and body fields for me
Show me an example URL like that and then give me a table, documenting all of the query string parameters that I need to know
Google Gemini gave me this example:
https://mail.google.com/mail/?view=cm&fs=1&to=recipient@example.com&cc=someoneelse@example.com&su=Email%20Subject&body=Hello%20There
Following that link redirected to almost the example I provided above.
Gemini also gave me this table:
| Parameter | Description | Example |
|---|---|---|
view |
Required. Sets the view mode to compose (cm) |
view=cm |
fs |
Required. Fullscreen mode (1 for on, 0 off) |
fs=1 |
to |
The recipient’s email address | to=recipient@example.com |
cc |
Email address(es) to CC (separate by commas) | cc=someoneelse@example.com |
bcc |
Email address(es) to BCC (separate by commas) | bcc=anotherperson@example.com |
su |
The email subject (URL Encoded) | su=Email%20Subject |
body |
The email body (URL Encoded) | body=Hello%20There |
That’s not entirely correct -the fs=0/1 option no longer does anything, and I found that view=cm should be replaced by tf=cm.