I built a minimal monthly habit tracker as a Firefox new tab extension

I tried every habit tracker app. Most are overkill — streaks, gamification, analytics, social sharing. I just want to know: did I do my habits today?

So I built Habit Tracker New Tab for Firefox — a minimal monthly grid that replaces your new tab page.

The design

A simple calendar grid: rows are habits, columns are days. Click a cell to mark it done. That is it.

No streaks, no scores, no notifications. Just a visual record of the month.

The extension has four themes: Journal (warm parchment), Night (dark blue), Ocean (light blue), Rose (pink). One-click switch between them.

Why monthly view, not daily

Most habit tracker apps show you today's habits. This is useful, but the motivation comes from seeing the month.

A full month on screen shows you patterns: you exercise every weekday but skip weekends; you read consistently but missed a week; the first week of the month is always your best.

That visual context is what makes the monthly grid more motivating than a daily checklist.

Technical notes

Everything lives in localStorage. The habit list and check state are both stored locally.

const HABITS_KEY = 'ht_habits';
const CHECKS_KEY = 'ht_checks';

function getChecks() {
  const raw = localStorage.getItem(CHECKS_KEY);
  return raw ? JSON.parse(raw) : {};
}

function markDone(habitId, day) {
  const checks = getChecks();
  const key = `${habitId}_${day}`;
  checks[key] = !checks[key]; // toggle
  localStorage.setItem(CHECKS_KEY, JSON.stringify(checks));
}

The table renders from the in-memory state on every new tab open. No server, no sync, no account.

What it does not have

No reminders — browser extensions cannot send push notifications without special permissions. And honestly, if you are relying on reminders to do your habits, the habit has not formed yet.

No analytics — tracking your 7-day rolling average completion rate adds complexity without changing behavior. The grid itself is the feedback.

No social features — habit tracking is personal. Sharing streaks is gamification. I wanted the pure version.

Install it

Habit Tracker New Tab on Firefox Add-ons

Free, local, no account. If you want a minimal monthly habit grid on every new tab, install it.

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The simplest version of a tool is often the most sustainable. No gamification means no fatigue.