How to insert HTML email with variables in Gmail

To insert an HTML email with variables in Gmail, mark the bits that change with {{ident}} tokens, fill this send in html2email Preview, then hit Insert. The extension replaces names, CTA links, images, and HTML blocks before the letter hits compose. Gmail gets baked HTML, same as a normal formatted send. Tokens stay in the editor.

We built this for people who send the same layout to Mira on Tuesday and to Alex on Thursday from Gmail, without opening Mailchimp. Quotes, membership updates, project notes: one template, fill new values, then Insert.

What are HTML email template variables?

A variable is a named placeholder in the markup:

• {{ident}} only. Ident starts with a letter or underscore, then letters, digits, underscore.
• No {{name|default}}, no Mailchimp *|FNAME|*, no Gmail @firstname chips.
• The same ident in five places is one field. Change it once, Preview updates all five.

Edit HTML still shows the token. Preview shows the substituted letter plus a {} badge with the unique token count in the current HTML. In our 1.9.0 tests, a membership-update builtin used nine fields (greeting name, headline, HTML body, CTA, hero, and so on). Badge said 9. That count is tokens in this letter, not the whole library.

How do I insert an HTML email with variables in Gmail?

1. Install html2email (Gmail/Yahoo) and pin it.
2. Open Compose, click the html2email icon.
3. Load a template, or paste HTML, or type {{clientName}} in Edit HTML.
4. Switch to Preview. Click the {} badge (or pick a line of text, a link, or an image).
5. Fill this-send values. Empty value uses the library default.
6. Insert. html2email bakes, then drops formatted HTML into Gmail.

Copy HTML uses the same fill panel, then copies baked markup. Save stores tokens in the template. Session values stay while this dialog is open; they are not written back into the field library.

How is this different from Gmail mail merge?

Gmail's own mail merge personalizes a blast with @firstname tags from Contacts or a Sheet. Google’s Help article lists the flow: Compose → Use mail merge → type @. Merge tags do not work in every Gmail message type. The product is built for many recipients in one send.

html2email Variables fill one HTML letter you are about to send. You reuse the layout, type Mira's name (or her booking URL) in the panel, Insert, send. There is no Sheet and no ESP. Same Gmail send you already do.

Need	Use
200 contacts, first name from a Sheet	Gmail mail merge (Google Help) or Apps Script {{First name}}
Same HTML letter, new client, new CTA, today	html2email Variables, then Insert
Saved Gmail canned template	Keeps formatting. No {{merge}} fields
List-blast from Mailchimp / Klaviyo	Those tools' merge tags. Different product

Source for native merge: Send personalized emails with mail merge. Apps Script sample uses {{Column Header}} mapped to Sheets, which is still a bulk pipeline, not a compose-time HTML editor.

What variable types can I use?

Pick the type that matches the slot, or html2email infers it when you click a link or image in Preview.

Type	Token example	What bakes
Text	{{clientName}}	Escaped text. "Hi Mira,"
Link	{{cta}}	Title + URL on the <a>
Image	{{hero}}	HTTPS src on the <img>
HTML	{{updateHtml}}	A sanitized block (no script / iframe / on* handlers)

Tokens inside attributes such as alt stay as values only. Wrapping those in a preview <span> would split the quote and dump tag leftovers as visible text. We learned that the hard way in Preview QA. href and src get chrome on the owning tag instead.

How do I add a field without rewriting the letter?

You can type tokens in Edit HTML, or pick elements in Preview.

• Edit HTML. Type {{projectDate}} where the date sits. Create the field from search if it is new.
• Pick in Preview. Turn on choose-fields, click the greeting, the button, or the hero. Assign to an existing library field or create one from the selection.

The library is global for the extension. It is not stored per template. Open a builtin that ships with slots and html2email seeds missing names. Your saved templates keep tokens in the HTML only.

Do merge tags appear in the sent email?

Bake runs on Insert and on Copy HTML:

1. Read every {{ident}} in the current HTML.
2. Replace with this-send value, or default if the value is blank.
3. If any valid token remains, stop. Error lists the leftovers.

If a known field has both empty default and empty value, you get one confirm per session ("insert anyway?"). Dismiss and those bake to empty string. That leak guard ships in 1.9.0. It is not a Mailchimp-style fallback filter.

Can I reuse one HTML template for every client?

Save the letter to My Templates with tokens still in the source. Next send: open it, change clientName, swap the CTA URL, Insert.

Example we use internally: a membership-update HTML with Hi {{clientName}}, a headline slot, an HTML body, and a mailto CTA. Per recipient we only fill the name. Headline and body stay on defaults until a campaign week needs new copy. Small SaaS and local-service buyers already send this way from Gmail. They were not looking for another ESP.

Capture still helps when the starting point is someone else's mail. Pull the body, mark the name and the button, save. Next time you skip the HTML hunt. See the welcome walkthrough for pin → insert → capture.

How do I change a CTA or hero image per send?

Assign the <a> as type link. Fill Title and URL for this email. The baked href must still be a real URL. The link checker in Editor is the place to catch 404s and UTM edits after bake, or on the static parts of the template. Guide: valid href in email.

Hero: assign the image, paste an HTTPS src. Host the file. Drive share links fail in clients the same way they fail in a signature.

What happens if a field is empty on Insert?

• Value set → that string (or URL / HTML) bakes.
• Value blank, default set → default bakes. No prompt.
• Both blank → confirm once, then bake empty, or cancel and fill.
• Stray {{oops}} that is not a known ident still matches the token pattern → Insert blocked.

Defaults live in the Variables library UI, not inside the token. That keeps slots with HTML values readable.

Common mistakes

Spaces in the name. {{First name}} is not a slot here. Use {{firstName}}. Apps Script merge uses column headers with spaces; we do not.

Expecting Gmail @ tags to fill html2email tokens. Different systems. Bake happens in the extension, before Gmail sees the body.

Pasting raw HTML into compose. You still need Insert so Gmail renders tables, not tags. Variables do not change that. Same rule as Vacation responder.

Sending a list from Variables. One compose, one recipient (or a normal To: line you type). For a 500-row Sheet, use Gmail merge or an ESP.

Conclusion

Mark {{ident}} in the template, fill Preview, then Insert. html2email bakes first. You keep one client-ready layout. Names, links, images, and HTML blocks change per send. Tokens never leave the editor. That is the 1.9.0 workflow: one HTML template, many clients, from Gmail. Not a new ESP.