Quick Answer: An auction house bot automates the buy-low, relist-high loop. It buys listings that clear your margin, reposts at a price that sells, and undercuts when someone lists beneath you. Undercut is a free, unofficial Windows app with an in-game panel built for WoW Forever. It checks fees, sell speed, and trap items before it spends any gold.
The biggest number on a flipping tool's screen is usually the worst item to buy. You end up with a bank tab full of recipes nobody has wanted since the last patch. An auction house bot tries to fix that by asking a harder question before it spends a single coin: will this actually sell, and at what price? Undercut, a free project aimed at WoW Forever, does exactly that. Here's how it works, where it falls short, and whether the risk is worth it.
What an auction house bot actually automates
Flipping is a loop with three moving parts: buy under market, relist above your cost, and wait for a buyer. Most of the real work sits in the arithmetic and the waiting, and that's where manual flippers lose the most time.
Undercut runs that loop on its own while the game is open. It buys every deal that clears your margin, reposts at the price that sells, and cancels the relist when the market moves. It also undercuts back when someone lists under you. Every buy and post gets logged, so you can see what it did and why.
Before you turn any bot on, write down the margin you need after the auction house's cut and the deposit you could lose. A bot will happily execute a bad plan at scale. The margin you set is the only guardrail you have.
Three questions every flip has to answer
Undercut frames each deal around three questions, and the framing is the most useful idea in the project:
- What would I really keep? It subtracts the auction house's cut and the deposit, then shows the remainder.
- How many should I buy? It buys the cheapest listings first and stops at your margin, your budget, or the point where you'd own more stock than you can sell.
- Will it sell? It estimates how long you'd wait in line behind everything listed under your price.
The output is written in plain language. The project's own example reads: "Buy 20 up to 2g 37s and relist near 3g 20s. About 42 sell a day, so expect to wait 2.1 days. You keep about 15g 48s after the auction house's share."
Notice what that sentence hides. A 15g profit that takes two days to realize is a different investment from one that clears in ten minutes. Gold tied up in your mailbox is gold you can't redeploy. Here's where most flippers get tripped up: they judge deals by the margin and ignore the queue.
Why the biggest margin is usually the trap
The counter-intuitive part is that the best-looking margin is often the worst deal. Sorting by percentage gift-wraps your worst mistakes. The project's example list makes this concrete, though these figures are illustrative from its own page, not live prices:
| Item | Looks like | Why it's a trap |
|---|---|---|
| Formula: Enchant Weapon - Crusader | +312% | Fewer than one sells a day, so your gold sits in the mailbox |
| Arcane Crystal | +102% | The "normal" price is two weeks old, and the market has already slid |
| Black Lotus | +67% | Cheap, but 21 days of listings sit ahead of yours |
Each trap fails differently, and each failure has a clear cause and effect. When sell-through is low, your relist waits, your capital freezes, and you pay the deposit while the item rots. When the reference price is stale, you buy against a number that no longer exists. When supply is already listed ahead of you, your position in the queue decides your timeline, not your price.
Undercut flags all three and tells you why. That's the main value: it doesn't just rank deals, it explains which ones to skip.
Where the numbers come from, and why sales are a guess
Every price in Undercut comes from recorded auction house scans. That means a price is only as fresh as the last scan. If your snapshot is two weeks old, the margin you see may describe a market that no longer exists. Check scan age before you trust any ranking.
Sales are harder. The API never reports a sale directly, so Undercut compares snapshots over time and counts auctions that vanished while time was still left on the clock. The problem is that a cancelled auction looks exactly like a sold one. The project says so openly, and it's the right call. Treat "about 42 a day" as a rough guide, not a forecast.
Here's the practical rule: if a deal only works when the sell-through estimate is exactly right, it's fragile. Build your plan so it still breaks even at half the estimated rate.
Is an auction house bot safe to use?
Is an auction house bot safe to use? The honest answer is that it depends on what you mean by safe, and nobody can promise you a result from Blizzard.
On the code side, the project makes specific claims. It stays inside the auction house, it doesn't read game memory or files, and it's released free with viewable code. That aligns with Blizzard's add-on policy, which requires add-ons to be free with viewable code. The project's README also states that the project is unofficial and not endorsed by Blizzard.
On the account side, the risk is different. Automating trades is still automation, and the terms of service decide what you can do. If you use any bot, keep the volume sane and read the rules. A few practical steps reduce your exposure:
- Start with small margins and a low budget cap, so one bad scan can't drain you.
- Keep the number of automated actions modest rather than maxing out every slot.
- Pause auto-buy during patches or unusual market events, when prices and listings shift fast.
- Re-read the project's rules document before each major update.
That said, a conservative configuration reduces risk but doesn't remove it. Treat any bot as a tool you're responsible for.
Undercut versus the tools you already know
Undercut isn't the only option. The project's own competitor comparison lists TradeSkillMaster, AuctionFlip, FlipQueue, and Saddlebag Exchange. Read it before you commit to anything. Here's how I'd frame the trade-offs based on that comparison:
- TradeSkillMaster is the broad suite. If you want auction tools, crafting, and inventory in one ecosystem, it's the default. Undercut is a narrower bet on buying and posting automation rather than a TradeSkillMaster alternative for everything.
- AuctionFlip is the closest rival on flip scoring. Its confidence and liquidity scores overlap with what Undercut does, and it's retail-only.
- FlipQueue needs TradeSkillMaster for its Deal Finder, according to the project's table, so factor that dependency in.
- Saddlebag Exchange works on the web and is a good option if you want analysis without installing anything in game.
Undercut's distinct claims are that it buys and posts for you, and that it states the reason for each decision in a sentence. The project's table marks several rivals as "Not stated," which means the public page doesn't mention the feature. It doesn't mean the tool can't do it, so verify before you assume.
Setup, and what's still rough
You'll need Rust, Node.js 22, and the Tauri prerequisites if you're building the desktop app. Windows 11 already includes the WebView2 runtime. For a quick look at the screens, npm run dev in the app folder opens them in a browser without a Rust build.
The Windows installer isn't code-signed yet, so SmartScreen will likely warn you. Choose More info, then Run anyway, but only if you downloaded it from the official repository's releases page.
Here's the honest status from the project:
- Flip math and trap checks work and have tests.
- Auto-buy and auto-post work in game and are logged.
- Live price fetching works from recorded scans. The
MarketSourceinterface is where a live feed would plug in. - The addon window works in the game client.
The gap between "works from recorded scans" and "live feed" is the part to watch. Until a live source is wired in, your decisions depend on how recent your snapshot is.
Frequently Asked Questions
What is an auction house bot?
An auction house bot is software that automates buying, posting, and repricing items on the in-game auction house. Undercut, for example, buys listings that clear your margin, relists at a price that sells, and cancels when the market moves. It only works inside the auction house and stops when you close the game.
Is an auction house bot safe to use in WoW?
Nobody can guarantee that. Undercut stays inside the auction house and doesn't read game memory or files, which aligns with Blizzard's add-on policy. The account-level risk comes from automation volume, so keep your activity modest and read the rules before you rely on any bot.
Why does a flip still lose money when the margin looks good?
Margin is only one variable. If sell-through is slow, your gold sits in the mailbox, and if the reference price is stale, the market may have already moved. A deal can clear your margin on paper and still lose time, which costs you in opportunity terms.
How accurate is the "about 42 a day" sales figure?
It's an estimate. The API doesn't report sales, so Undercut counts auctions that disappeared with time left on the clock. Cancelled auctions look the same as sold ones, so treat the number as a rough guide and plan for a lower rate.
Pick one flip and test it by hand this week
Before you trust any auction house bot with your gold, run the three-question check yourself. Write down your margin after fees and deposit, compare it to the sell-through estimate, and note whether you'd still buy if the rate were half what's shown. Undercut's free build makes this easy to test, and the reasoning matters more than the software. Pass this to someone wrestling with dead stock in their bank tab, because the fix is usually a better queue check, not a bigger margin.