No. 4 on Poland's shopping Top Grossing chart, which is really just one or two annual subscriptions: Restockalert and the "size restock alert" micro-business

Restockalert is a restock alert tool built by one person in the UK: paste a Zara product link, pick your size, and you get notified when it's back. In Nov 3 its iPhone app surged to #4 on Poland's App Store shopping Top Grossing chart, at a time when it had zero ratings. The chart looks busy, but when you break it down there are probably only one or two subscriptions behind it. The real thing to learn is how it found users for very little money, and which kinds of people this need is strongest among.

A Reddit reply

In 2026 Jan 5, someone on r/Sneakers asked, "How does everyone monitor restocks?" A person signing as Talha replied: "So I built restockalert.me." Over the following months he kept doing this: under "Will Zara's discounted items restock?" on r/FrugalFemaleFashion he replied, "I ended up building an app myself that alerts you when Zara items come back in stock"; and under a 2021-year-old thread on r/Doesthisexist asking "Is there a site that notifies me when an online store restocks?", he pointed people to app.restockalert.me to track Free People items.

People who want this exist, and they're in a hurry. On r/FreePeopleFinds there's a "restock tower" thread for the Free People Emerson bag, started in 2026 May, now with 1,459 comments, mostly users shouting at each other: "The small in Santorini blue is back!" "Large in terracotta is back!" One commenter wrote: "I saw it sitting on the site for two days in early May and didn't buy it, and now I'm paying for it, checking every day."

What it is

The first line of the store page is "Sold out in your size?" The flow has three steps: paste the link, and it automatically pulls the product name, price, and per-size stock; tick the size you want; and you get a notification when that size returns, with one tap to the product page. It supports Zara, H&M, Mango, COS, Bershka, Sephora, Coach, Net-A-Porter, Target, and more, with the website claiming 162+ stores in total. It doesn't place the order for you; it just tells you "it's back."

It's mainly a web product. The website and blog have existed since early 2026, and the iOS, Android, Chrome, and Firefox versions were added together in late August. The iPhone app went live in Aug 28, published by Securitty Ltd, a UK company, with accounts synced between the web and the app.

Pricing is tiered by speed. The free web tier can monitor 1 items, checks once every 3 hours, sends only email and browser push, and expires after 4 days. Premium is about £4.50 a month billed annually, monitors 25 items, checks every 5 minutes, and adds Telegram, mobile push, and price-drop alerts. The pricing page says something refreshingly candid: "Every check, we actually make a request to the retailer. The free tier exists because we check every three hours." In-app purchases have two tiers: Serious at £3.99/month or £29.99/year, and Pro at £7.99/month or £59.99/year.

Did it take off? No, the charts are just shallow

Here's how its Top Grossing rank moved (App Store, Poland shopping category): from Oct 28 to Nov 2 it sat around 137 to 138, then in Nov 3 jumped to #4, after which it went #11-04 to #10, #11-05 to #18, and #11-06 to #24, dropping a notch each day. Croatia and Sweden followed the same pattern, sliding further down.

Jumping up first and then falling day by day is exactly what a single payment looks like: someone bought an annual plan (likely the £29.99 or £59.99 tier) on a given day, the revenue entered the chart's rolling window, and it slowly slid out. If there were steady recurring payments, the rank would hold at one position instead of moving like this.

It can climb this easily because the pool is so shallow. In Nov 6 Croatia's shopping Top Grossing chart had only 159 apps total, not even enough to fill 200 spots; around Poland's #24 spot there's a run of apps with 0 to 7 ratings. On a chart like that, a few sales are enough to reach the top 30.

Install numbers back this up (store pages, 11-06): the iPhone app has 3 ratings on the UK store and 2 on the US store, and 0 everywhere else; Google Play shows "50+ downloads"; the Chrome extension has 13 users; the Firefox add-on has 6 daily active users. The website homepage claims "12,400+ items being monitored and 38,250+ alerts sent," which can't be verified. A person usually tracks several items, and this figure more likely reflects cumulative numbers the web version built up over half a year.

So to be accurate: this is a small web tool that's been around for about a year, recently added an app, and brings in revenue sporadically. It's not a product that's gaining momentum.

Where users come from

It spends almost nothing on acquisition. There are two tactics, both suited to a solo founder.

Reply to old Reddit threads that rank highly on Google. When people search "Zara restock alert," Reddit help threads often appear in the top results, some several years old. Replying "I built one" under them captures long-tail search traffic that keeps working. The replies above all came this way.

Write a Q&A blog around one brand. Almost all of its blog posts are Zara questions: "When does Zara restock?" "What does Zara's Coming soon mean?" "What if Pull&Bear, Bershka, or Stradivarius is sold out?" Searching "zara restock alert" puts its blog in the top 10, alongside same-topic articles from generic web monitoring tools like Visualping and PageCrawl.

The rest is small. The official subreddit r/RestockAlertMe announced the iPhone, Android, Chrome, and Firefox versions; the Instagram account @restockalertme posts product images with no visible impact; the website has only a Turkish-language version. No one has mentioned it on X in nearly 90 days, and there's no media coverage or Product Hunt launch. Whether it runs ads is unknown.

Who it's competing with

The barrier is so low anyone can build it. In Aug 28, a mom on r/FreePeopleFinds said her computer-science son built her a Free People restock alert tool and wanted to know if anyone else would use it. On r/passive_income someone posted "32 people pay me $3 a month to send board game restock alerts", which works out to under $100 a month.

Where this business gets stuck

Looking at it closely, size-restock alerts have three hard problems:

• Users leave after one use. Once the item they waited for is back in stock, or they give up waiting, there's no reason to stay. That's why the free plan expires after 4 days and the paid plan after 90 days. The product knows this, and most people are coming for one specific item.
• The brands run it themselves, for free. Zara's official back-in-stock notifications are enough for most people. Only a small group wants something "faster, across stores".
• Every extra user adds scraping cost. Checking every 5 minutes means constantly requesting retailer pages, and maintaining it when anti-bot defenses kick in. The pricing page says as much.

The tools that actually scaled targeted different audiences: TYPA tracks Labubu, PokeNotify tracks Pokémon cards. Those buyers chase limited drops that sell out in minutes, come back repeatedly, and pay willingly. Clothing-size shoppers want one specific size, and the urgency passes.

If it were you

Verdict: C. Worth learning from, but not worth copying as-is. Size-restock alerts already have free official features, general-purpose monitoring tools and several similar small products. The revenue ceiling is low, and this one hasn't broken out yet. What's worth taking from it: its acquisition methods, and the pricing idea of charging by how often you check.

Good fit for: People already inside a scarcity-driven community, like sneakers, collectibles, trading cards, vinyl or a brand's limited bags. You know where people hunt for stock and what they fear missing.

Bad fit for: Anyone building a general "monitor anything" restock tool that competes head-on with Visualping and brands' own features, or anyone counting on organic app store traffic.

How to do it: Pick a category with limited, instantly sold-out, recurring drops, not mass fast fashion sizes. Start on the web, add an app and browser extension later, with one account and one subscription across all of them. The free tier checks slowly, the paid tier checks fast, and you sell the "minutes faster". If you want to go into apparel, pick one product with a passionate community, like the Free People Emerson bag, which has thousands of restock threads, rather than taking on 162 stores at once.

How to get users: Follow Talha's approach: answer old help threads on Reddit that rank high on Google, and reply in restock threads in that community. Then write Q&A content around one brand, such as "when does X restock" or "what does this status message mean". The cost is close to zero, but it's slow, so measure it monthly.

Timing: No hard deadline. Scarcity categories follow hype: when Labubu or Pokémon-style interest fades, demand disappears, so pick what people are chasing right now.

What would show this read is wrong: If Restockalert stays in the top 30 of Poland's or another small country's Shopping chart for several weeks instead of spiking and falling, and its rating starts climbing, it has a real base of paying users and clothing-size alerts are more promising than assessed here. If Zara extends its notifications to all sizes with app push, this direction is effectively closed.