In validation · demand check before any code

Know what changed on a page — without reading a raw diff

ChangeBrief is a planned browser extension that watches pages you choose and, when something changes, summarizes what changed and whether it matters in plain language instead of handing you a screenshot comparison. It is not built yet. This page exists to answer one question first: do enough people want change monitoring that explains itself to justify building it? If yes, it gets built. If not, it doesn't.

Why this shape

The category is proven: Distill Web Monitor lists over 2,000,000 Chrome downloads, Visualping claims over 2,000,000 users, and the open-source changedetection.io project has more than 30,000 GitHub stars (figures checked 2026-10-09).
People already pay for this: Distill's cloud plans start at $12/month, changedetection.io's hosted plan is $8.99/month, and Visualping runs from $10 to $250/month.
The recurring complaints about existing tools are false alarms and raw diffs that still leave you to work out what actually changed. A short, graded summary is the gap this idea tests.

Planned capabilities (none of this exists yet)

Watch a whole page or a specific element (a price, a stock badge, a job listing, a policy line)
Checks run locally in your browser while it is open — no account needed for the free tier
Each change reported as a brief: what changed, how significant it looks, and the before/after values
Free tier (planned): up to 5 watched pages, local checks
Pro (planned): more watched pages, AI summaries, check history

One limit, stated plainly: a local-first version can only check while your browser is open. It cannot promise round-the-clock cloud monitoring, and this page does not pretend otherwise. If that limit makes it useless for you, that is exactly the kind of answer this validation needs.

Who this is for

People tracking competitor pricing, restocks, job postings, or policy and documentation pages
People who tried a change monitor and gave up on noisy alerts or unreadable diffs
If a free tool already covers your needs, you do not need this — say so in the registration email; it still helps the decision

Indicative price (not a live price — nothing is for sale, no payment is taken)

$29 one-time for Pro

ChangeBrief is not built yet. Nothing is for sale today, and no payment is taken. If the extension is built, the indicative price will be $29 one-time for Pro. Development only begins if 20 people join the waitlist by November 9, 2026; otherwise, the project is dropped and registrants are notified by email. Registering means sending one email and answering what tool you use today to watch pages.

The price and threshold are test parameters for this validation, not market conclusions.

Questions

Can I use it now?
No. Nothing has been built; this page is the whole thing.

Does registering mean I have to buy it?
No. It only means "notify me if it launches". Decide when there is a real product to look at.

Why no cloud monitoring?
Cloud checking means servers, and servers mean a subscription. This test starts with the cheaper, local shape and an honest statement of its limit; registrant answers will show whether that trade-off works.

Why validate before building?
Change monitoring is a crowded category with strong incumbents. Building first and hoping would waste your attention and my time; a signup count plus real answers about current tools is a cheaper, more honest test.