If you’ve seen the name pop up in a comparison post and wondered what it actually does, here’s the short version: buildzcrank is a free, real-time AI overlay for League of Legends that reads your live game state — champion select, gold, items, enemy comp, cooldowns — and tells you what to do next, without you tabbing out to a website. This article breaks down every piece of it: the five AI systems, the three overlays, and the tools you can use outside of a match.
What buildzcrank actually is
Buildzcrank is a standalone desktop app for Windows that watches your League of Legends match through Riot’s official Live Client API and gives you contextual advice at each stage of the game: champion select, the match itself, and the post-game review. It doesn’t run inside Overwolf, doesn’t inject code into the League process, and doesn’t read anything from memory — it only reads the same local game-state data Riot exposes to any third-party tool and draws its own overlay windows on top.
The core idea is the one described in how real-time AI build recommenders actually work: instead of showing you the average build across millions of unrelated games, it reads your specific game — your gold, your items, the enemy composition, the current patch — and updates its suggestions as the match changes. That’s also what separates it from apps built around post-game history review, a distinction covered in more depth in AI coaching vs. AI overlay: what’s the difference.
The five AI systems inside buildzcrank
Buildzcrank isn’t one model doing everything — it’s five separate systems, each built for a specific moment in the game:
Item Predictor. Reads your live gold, inventory, and the enemy’s items in real time and reorders your next-purchase priority as the game state changes. If the enemy top laner buys a Banshee’s Veil, the model can push a penetration item up your list immediately — no waiting for a website refresh.
Draft Recommender. Watches picks and bans as they lock in during champion select and ranks the strongest picks for your role based on team synergy and known counters. It doesn’t just suggest a champion — it can also import a matching rune page automatically when you lock in.
Phase Advisor. Gives you a win-probability read for the early, mid, and late game against your specific matchup, with contextual advice attached (for example, telling you when a lane is winnable enough to press an advantage).
Post-match Coach. After the game, an LLM reviews your stats phase by phase and gives you plain-language feedback — what you did well, what to fix next game. This is the one feature that requires linking a Riot account, since it needs your match history to analyze.
Skill Hint. Tells you which ability to level up based on your champion’s guide data. It works without an account, which makes it the easiest system to try first.
Ahri Ahri mid into a heavy engage draft is a good example of how these connect: the Draft Recommender flags the matchup risk in champion select, the Phase Advisor tracks your early lane win probability, and the Item Predictor adjusts your build the moment the enemy jungler shows up with a lead.
The three in-game overlays
The AI systems above surface through three draggable, always-on-top overlay windows that sit over League itself. You can set each one to stay visible permanently or only appear while holding TAB, and they work in windowed or borderless mode (not exclusive fullscreen, since Windows won’t draw an overlay over an exclusive-fullscreen game).
- Shop / next-item overlay — shows the Item Predictor’s current top pick, updated live.
- Lane gold overlay — compares your gold-in-items against your lane opponent, plus team totals, so you know exactly how far ahead or behind you actually are instead of guessing from the scoreboard.
- Enemy summoner cooldown tracker — click a summoner spell icon when you see the enemy use it, and buildzcrank tracks the cooldown for you (Flash, Smite, Ignite, and the rest).
None of these read data Riot doesn’t already expose — they just organize it faster than you could by alt-tabbing to a stats site mid-fight.
What you can do without a live match
Not everything in buildzcrank requires an active game. The “Explore” side of the app covers the parts of League prep that happen before or after you queue:
- Tier list — a browsable champion tier list you can check without launching the client.
- Draft Lab — simulate a full 5v5 draft offline and ask the Draft Recommender for pick suggestions, useful for practicing champion select without the ranked timer pressure.
- Champion guides — skill order, power curve, rune pages, and a power-stat radar for each champion, similar in spirit to what static guide sites offer but pulled from the same models that adapt live in-game.
- Coach Lab — run the Post-match Coach against sample matches to see what kind of feedback it gives before deciding to link your own Riot account.
Requirements, accounts, and data privacy
Buildzcrank is Windows 10/11 only — there’s no macOS or Linux build. It’s free to use; for a broader look at how the main companion apps compare on price and features, see the full 2026 LoL companion app comparison.
Buildzcrank has no affiliation with Riot Games and doesn’t require Overwolf, a point covered in detail in the Overwolf question and why it matters for LoL apps if you’re deciding between an Overwolf-based tool and a standalone one.
How to get started
Setting up buildzcrank
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Download and install
Grab the Windows installer and run it — no Overwolf or third-party launcher needed.
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Queue into champion select
The Draft Recommender activates automatically once picks start locking in.
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Play with the overlays on
Toggle the shop, lane gold, and cooldown overlays to always-visible or TAB-only, whichever fits your playstyle.
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Check the post-game review
Link a Riot account when you're ready to get phase-by-phase feedback on your own matches.
Frequently asked questions about buildzcrank
Is buildzcrank free?
Yes. The full suite — all five AI systems and all three overlays — is free to use.
Do I need Overwolf to run buildzcrank?
No. Buildzcrank is a standalone Windows app that draws its own overlay windows; it doesn't run on top of Overwolf or any other platform.
Does buildzcrank read memory or modify the game client?
No. It only reads data from Riot's official Live Client API and draws overlay windows on top of the game — it never injects code into League or reads process memory.
Do I need to link my Riot account?
Only for the Post-match Coach, since that feature analyzes your match history. Skill Hint and the overlays work with no account at all; the Item Predictor and Draft Recommender need an account but not a linked Riot account.
Does it work in exclusive fullscreen?
No — like any overlay app, it needs windowed or borderless mode, since Windows doesn't let third-party overlays draw over an exclusive-fullscreen application.
The short version
Buildzcrank packs five separate AI systems — Item Predictor, Draft Recommender, Phase Advisor, Post-match Coach, and Skill Hint — behind three in-game overlays and a set of offline tools (tier list, Draft Lab, champion guides, Coach Lab). It’s free, it’s Windows-only, and it doesn’t need Overwolf to run.
If you want to see how the recommendations actually change mid-game rather than just reading about it, the best way is to queue up a normal game with the overlays on and watch the shop overlay update the first time the enemy team changes their build.