"Learn's built-in calendar sucks so I built my own": a deadline extension for Waterloo students, 7 weeks, 2,500 people using it

WATnow is a free Chrome extension made by an electrical engineering undergrad at the University of Waterloo: it puts every course's deadlines from the school's Learn (Brightspace) into a sidebar, and when a professor moves a date it automatically strikes the old one and flags the new one. Launched in Sep 19; the author posted short videos on Instagram one after another to pull in classmates, and by October it had 1,541 installs. The site now says "2500+ students". The numbers are small and it doesn't make money. What's worth watching is how a student pushed a tool anyone could write up in two weeks at the start of term, and whether you can use the same playbook.

A "comment WAT" Reel

2026 Sep 16, second week of the University of Waterloo fall term: Instagram account @sleppyeric posted a Reel whose caption opens with:

"Learn's built-in calendar sucks so I built a replacement. Comment 'WAT' for the waitlist link" (Learn's built-in calendar is terrible, so I built a replacement. Comment "WAT" to get the waitlist link.)

A line below it reads: "If you're at another school that uses Learn, comment and I'll help you install it."

The poster is Eric Zou, an electrical engineering undergrad at Waterloo, whose LinkedIn lists second place in the SpurHacks 2025 startup track. Two days later he posted on TikTok "Join 400 students on the waitlist" (that post got 952 views); the extension launched on Sep 19. Over the next month he posted at least three more Reels, with the numbers in the copy climbing each time: 9-23 "comment WAT for early access link", 9-28 "now open to 6 schools, joined by 500+ students", 10-17:

"I built a tool used by 2000 students to sync their deadlines. Comment 'watnow' to get the download link"

Every one runs the same mechanism: no link in the post, you comment a word, and an automatic DM sends you the link. Comments push the Reel to more people at the same school and in the same city.

What it is

Install it, click the icon to pick your school, open Learn once, and the sidebar fills in: every course's assignments, quizzes, labs and discussions, sorted into Overdue / Today / This week / Next week / Later. No syllabus upload, no signup, no password. It uses the session already logged in in your browser.

A few details are what people remember it for (all stated on the store page and site):

• Professor date changes: every 30 minutes it re-reads the course page. When a date changes, the new one is highlighted, the old one is struck through in red, and the item moves to the week it now falls in. The site headline says it outright: "Every Learn deadline, kept up to date when profs move them".
• Stops reminding once submitted: when Learn or Crowdmark shows you've submitted, reminders stop. If you tick it off yourself but the system never saw a submission, the last reminder still goes out, and the item is marked in the list.
• Reminders by type: one slider each for assignments, labs and quizzes, from 7 days ahead to the morning of the due day.
• Works offline: if the course page can't be read, it shows the last list it got.
• Connects to Crowdmark: many Waterloo courses submit work through it, and generic tools usually don't support it.
• Read-only and open source: the code is on GitHub under the MIT license, and the README opens by saying you can see exactly how it touches your school account before you install. The only outbound data is an anonymous install and usage count.

About 70% of people who installed it open it again within a week, which is very high for an extension (author's self-reported figure, sample of 1,500 people). The reason is simple: deadlines get checked every day, and the sidebar stays pinned. Store reviews say the same. In Sep 24, one wrote "God bless, I can finally stop hunting for due dates everywhere, I have so much homework"; in Sep 26 someone asked if it could export to a calendar, and the author replied "working on it, Google Calendar PR is already up." By October, .ics export had shipped.

Why this one took off

"Put all your LMS deadlines in one place" is hardly new. Tasks for Canvas launched on the Chrome Web Store 2021 years ago and now has 1M users. In just 2026 years, more than a dozen student-built clones have shown up on the Chrome Web Store: the University of Ottawa's Brightspace Dashboard launched in July, two months before WATnow, with similar features plus AI that picks up exam dates, and reached 6 81 users by November. UIUC's Illini Dash, Canvas+, and DeadlineSync for Moodle each have 24 to 300 users (Chrome Web Store, 11-06).

The tools are similar, but the results differ by dozens of times. Three things account for the gap:

Pick one school. The name is an in-joke for the school (Waterloo is "WAT"), and the copy just says "Learn," which is what Waterloo students call Brightspace. Crowdmark is supported too. The first reaction from anyone who sees it is "this was built for our school."

Launch in the first two weeks of the semester. Classes started in Sep 9, teasers ran from 16, and it went live on 19. The first two weeks are when everyone copies syllabi, builds calendars, and gets burned by a professor moving a deadline for the first time.

The author did distribution himself. He built a waitlist before launch, so hundreds of people were waiting to install on day one. Every Reel used "comment a keyword to get the link." The copy kept citing user counts (400, 500, 2000) as social proof. He replied to every store review in the tone of a classmate ("tysm brother", "YOO we on that RN!"). There was no paid ads or press coverage, and no discussion on X. The TikTok account had only a dozen followers. Most of the volume came from Instagram and word of mouth among students.

Expanding was nearly effortless: the Ontario schools here all use Brightspace on the same interface, so it was just a matter of changing the domain. From Sep 28 he added 6 schools at once.

Where the money comes from

No. The extension is completely free, with no in-app purchases and no paid tier on the site. Charging students is hard, and the author doesn't seem to plan to. His Instagram already teases the next product, an extension to help you find co-op internships faster. (Inference: the batch of same-school students WATnow built up is an audience prepared for the next product.)

Someone already copied it

DALnow, for Dalhousie (Nova Scotia) students, by developer fouaden, updated to version 1.1 in Oct 4. The store description nearly matches WATnow line for line: "updated when profs move dates," "Overdue, Today, This week, Next week and Later," "checks again every 30 minutes." It adds an Alt+K cross-course search. WATnow is MIT-licensed open source, so modifying and reusing it is allowed. (Inference: DALnow was built on its code.) Others have made Opera and Firefox versions on GitHub. In the first week of November, more Brightspace student tools appeared in the store, including Altera for CourseLink (Guelph, a school WATnow already supports) and Dusk, all with single-digit users.

In other words, the code is no longer valuable, since anyone can fork it. What's left is whether someone at that school pushes it.

If it were you

C: The distribution playbook is clean and worth learning, but as a business it's not worth pursuing. One school has a few thousand students, it's free, and the code is open source for anyone to fork, so the ceiling is low. It only works if you're actually at that school and willing to appear on camera for Reels yourself.

Who it's for: Student developers who are currently enrolled, whose school uses Brightspace, Canvas, or Moodle, and who want a first batch of real users and a project for their resume. Also people who want to build an audience at one school before launching a bigger product for university students.

Who it's not for: Anyone who wants to make money from it, anyone not on campus who can't speak as a "fellow student," and anyone building a general version for all of the US and Canada (Tasks for Canvas has 1M users and a rating of only 3.2; the catch with a general version is adapting to each school separately, not a lack of players).

How to build it: Fork WATnow (MIT), swap in your school's domain and name. It's a week or two of work. Add whatever is specific to your school (Waterloo's Crowdmark, which at your school might be a different assignment or course-registration system). Sell one thing only: "you won't miss a professor moving a deadline." Don't pitch it as a "study assistant."

How to get users: Copy the rhythm: post Reels a week before the semester to build a waitlist, using "comment a keyword and get the link via auto-DM." After launch, report user counts weekly. Reply to every store review. If people ask about other schools, open a waitlist for that school.

When to start: The next North American window is the winter semester starting in January 2027. Launch by late December at the latest and start building the waitlist. If you miss it, you wait until September.

Signs you're misreading it: ① The author starts charging (a paid tier, or selling to schools) and the money actually comes in, which shows this kind of tool can become a business. Bump the grade up. ② Copycat versions like DALnow passing 1,000 users in one semester at other schools means "do it again at another school" can be done at scale. A multi-school portfolio run by one person is a real path. ③ The other way around: if D2L already ships cross-course deadlines and reschedule reminders inside Brightspace, plugins like this will lose users.