Mailplate documentation and user guide

Getting started and connecting Gmail

Installing Mailplate, opening the app, and connecting the Google account you send from.

Mailplate has two halves that share one install. A Templates button appears next to Send in the Gmail compose window, and a full app opens from the extension icon for building and sending to a list. You need only the second to send.

Install

Add Mailplate from the Chrome Web Store. It works in Chrome, Edge and Brave, on Gmail on the web. There is no account to create with heyyoshi and nothing to configure before it works.

Connect the account you send from

Open the app, go to Email accounts, and connect a Google account. Google shows a consent screen naming exactly two permissions: one that can send mail on your behalf and cannot read it, and one that reads the address of the account you are connecting. Approve it and Mailplate can send as you. The token it receives is stored on your own device and used only to send; it never reaches heyyoshi, because there is no heyyoshi server.

To send from an alias such as sales@, verify it first under Gmail's own Send mail as settings, then type it into the campaign. Mailplate does not list your aliases through the API, because that would need a wider permission to learn something you already know.

Building your list of people

Importing a CSV, mapping columns, and adding the fields your business actually has.

The Leads tab is your book of people. Everyone you write to lives here, with whatever columns you keep on them, on your own device and uploaded nowhere.

Import a CSV

Import a spreadsheet, map its columns to fields, and the people land in the book. Five fields are built in: first name, last name, email, company and job title. Anything else is a field you add.

Your own fields

Add a field and it becomes three things at once: a column in the book, a box on the add-a-person form, and a {{variable}} you can drop into a message. Each field has a kind of value (text, email, phone, web address, number or date) and an example, so the format is never a guess. Deleting a field hides the column but keeps the values, so adding it back brings them with it.

Writing the message

Picking a design, merging your fields, and editing it like any Gmail message.

A message is one email, written once, with your fields merged into it for each person. You can write it plainly or start from a design.

Start from a design

In the Gmail compose window, press the Templates button or type ;; to open the picker at your cursor. Pick a built-in design or paste your own HTML. Pasted HTML is sanitised on the way in, and its CSS is inlined so it survives Gmail's renderer instead of falling apart the moment you press Send.

Merge your fields

Drop {{first_name}}, {{company}} or any field you added into the subject or the body, and each person gets their own copy with their own values.

Fill in the blanks

Parts left in square brackets are highlighted after you insert a template; Tab jumps between them and the first is already selected. The highlight is painted over the text rather than written into it, so nothing coloured reaches the recipient.

Sending, and pacing it like a person

Turning a list and a message into a paced send from your own inbox.

A campaign is a list, one message and a pace. Create one, choose the people, write the message, set the pace, and start it.

The pace

The pace is four things: how many to send a day, the hours of the day, the days of the week, and a random gap between messages. Together they mean forty emails do not go out at 9:00:00 and read as a machine; they go out across the working day the way you would send them by hand.

Cc, Bcc and send-as

Add a Cc or Bcc to loop a colleague in on every message, and set a verified send-as alias when a reply should go somewhere other than your main address. Cc and Bcc count against your Gmail limit, so two people in Cc spend three of your daily total per message.

Start, pause, resume

A campaign runs while your browser is open. Close it and the run pauses; open it and the run resumes where it left off. A campaign has a plain status the whole time: draft, running, paused or done.

Staying deliverable, and out of spam

Suppression, unsubscribe, the plain text part, and Gmail's own limits.

Sending from your own Gmail means your own reputation is the asset, so Mailplate does the things that protect it and refuses the things that would put it at risk.

Suppression

The Suppression list is addresses no campaign will ever write to. Every import checks it first, so somebody who asked to stop cannot be added back by a fresh file.

A real unsubscribe

Every message carries a List-Unsubscribe header Gmail recognises, so a reader gets an unsubscribe control at the top of the message rather than reaching for Report Spam, which is the thing that actually hurts your reputation.

Plain text alongside

Every send includes a generated plain text version next to the HTML, so it reads properly in a text client and looks less like a blast to a spam filter.

The only limit is Gmail's

Mailplate adds no cap of its own. Gmail allows 500 recipients a day on a free account and 2,000 on Workspace, and that is the ceiling. What gets an account limited is complaints, and the defence is a shorter, more relevant list, which is the kind of list this is built for.

Privacy, permissions and disconnecting

What it can and cannot see, the exact permissions, and how to disconnect an account.

Mailplate asks for one Gmail permission that sends and cannot read, and it reports to nobody. The full detail is in the privacy policy; the short version is here.

What it cannot do

It cannot see replies or bounces, because that needs a permission to read your mail and this asks for one that can only send. It does not track opens or clicks, because that means a tracking pixel, and it never sends automatic follow-ups. It only sends while your browser is open, because there is no server running it for you.

The permissions

The extension uses storage to keep your templates, your list and your campaigns on your device, identity to run the Google sign-in, and alarms to pace the send. It talks to four Google hosts and nothing else: Gmail, the Gmail send API, Google's userinfo endpoint, and Google's token endpoint for disconnecting.

Disconnecting

In the app, use Disconnect account, which revokes the token with Google and removes it from your device. Or remove Mailplate from your Google Account, under Security and third-party apps with account access. Uninstalling the extension removes everything it kept as well.