mailWarmer Docs
One side panel and a handful of tabs. Here's what each one does and what happens when you use it. Nothing is hidden and nothing is remote-controlled — what's documented here is what runs in your browser.
Quick start
mailWarmer is a Chrome extension that keeps your inboxes active. Install it, add your emails, and run — there's nothing to set up and nothing to pay for. It follows your browser's language: English or Português (Brasil).
Get going
- Add mailWarmer from the Chrome Web Store.
- Pin it to your toolbar so the icon stays visible.
- Click the icon to open the side panel.
- Add an email, pick newsletters, and hit Run.
Where things live
- 1 · Emails tab — add the addresses you want to keep warm.
- 2 · Run tab — subscribe an email to newsletters.
- Cookies & Profile — optional warm-up and signup details.
- Lists & Log — the newsletters and what happened.
Emails
Step 1. The email addresses you want to keep warm — add them here first, then pick one on the Run tab.
Manage addresses
Add, label, and select which inbox a run subscribes.
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Add an address
Local Default: —Type in any email address you want to keep active and give it an optional label so you can tell them apart.
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Active email
Local Default: First addedPick which address the next run will use. Only the selected address is subscribed when you hit Run.
Run
Step 2. This is where mailWarmer subscribes your chosen email to the newsletters you picked.
How a run works
One newsletter at a time, at a calm human pace — never a burst.
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Automatic signup
Auto Default: OnmailWarmer opens each newsletter's signup page in a tab, finds the form, fills in your email (plus any profile details the form asks for), and submits it.
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Human pacing
Auto Default: OnIt waits a few seconds between each signup so the activity looks natural, rather than firing off dozens of signups at once.
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Live progress badge
Info Default: OnThe toolbar icon shows progress as it goes: an orange running count during a run, then a green success count (or a red count if some failed) when it finishes.
Profile
Some newsletters ask for more than an email — a name, a city, sometimes a company. The profile fills those in for you.
Profile details
A set of believable, optional details used only to complete signup forms.
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Auto-filled on install
Auto Default: On first installmailWarmer seeds a realistic profile (name, location, phone, company, and more) the first time you install it, so signups work out of the box. You can edit any field.
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Edit your details
Local Default: —Change any of the fields to whatever you like. These details are used only to fill the extra boxes on signup forms — they never leave your browser.
Lists
The newsletters mailWarmer can subscribe you to. It ships with a curated list and lets you add your own.
The newsletter list
A ready-made list that comes with the extension, plus anything you add.
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Curated list
Auto Default: Built inA hand-picked list of quality newsletters comes with the extension and is updated with each new version of it. There is no account, and mailWarmer connects to no server.
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Add your own
Local Default: —Add any newsletter you like — a Substack publication or a regular signup page. Your custom additions sit alongside the built-in ones.
Log
A running record of everything mailWarmer does, so you can always see what happened.
Activity & history
What worked, what didn't, and when.
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Per-newsletter results
Local Default: OnEach signup is recorded for the email and newsletter it ran on, so you can see exactly which subscriptions succeeded and which need another try.
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Activity log
Local Default: OnA scrollable, time-stamped log of recent activity — handy if a newsletter behaves unexpectedly and you want to see why.
Privacy
Your emails never leave your browser.
mailWarmer never reads, opens, or sends from your inbox. Your email addresses and profile details stay on your device — they are only ever typed into newsletter signup forms, exactly like you'd do by hand.
mailWarmer has no server and sends nothing to anyone: no usage statistics, no tracking, no installation ID. The newsletter list ships inside the extension. The only requests it makes are the signups and cookie warm-up visits you start yourself.
Everything else lives in chrome.storage.local,
visible only to the extension. The full details are on the
Privacy Policy page, and
the source is on GitHub for anyone to read.
Changelog
0.7.0 — Português and zero server
mailWarmer now speaks Brazilian Portuguese as well as English, following your browser's language. It no longer has any server code at all: the newsletter list ships with the extension and nothing is ever sent anywhere. The tabs now follow the flow — Emails is step 1, Run step 2 — and every tab shows a one-line hint on hover. It also asks for fewer permissions.
0.6.0 — Toolbar badges
The toolbar icon now shows live progress: an orange running count during a run, then a green success count (or red on error). Cookie warm-up ends with a green badge of sites accepted. Full names show on hover, and status labels no longer get cut off in a narrow side panel.
0.5.0 — Cookie capture
Cookie warm-up now shows the cookies each visit leaves behind, with a per-site count you can expand and a total summary at the end. Recognizes more cookie banners and waits longer on slow sites.
0.4.0 — Cookies tab
Added the optional Cookies tab — a one-click warm-up that builds a natural-looking browser profile before signups run, with live progress and a summary.
0.3.0 — New side panel
A clean Gmail-style side panel with Run, Emails, Profile, Lists, and Log tabs. Optional profile to fill the extra fields some newsletters ask for, smarter form detection, and support for newsletters on custom web addresses.
Found something missing or wrong? Open an issue.