31st prototype — cheap CD keys, compare prices
Is it worth buying?
- The price is at or near its all-time low — a good time to buy.
Estimate based on public reviews (Metacritic/Steam) and price history — the final call is yours.
About the game
31st prototype is a steampunk puzzle adventure in which you guide a robot through maps while solving riddles. Its sketch-style visuals lend the game a retro atmosphere. It was both developed and published by STEAM STREET.
Best price today
€1.67
all-time low: official €1.67 near low
The cheapest 31st prototype key right now costs €1.67 at Steam. The lowest price we have recorded for this game: €1.67.
The average low over the past 5 months was €2.01.
Prices as of
Steam best price Official store
No offers match these filters — try widening them.
Listed seller price shown — payment fees may vary by method.
Lowest — official stores
€1.67
Oct 2026
Price history
last 89 daysMonthly price lows
| Month | Lowest official | Lowest keyshop |
|---|---|---|
| Oct 2026 | €1.67 | — |
| Sept 2026 | €2.09 | — |
| Aug 2026 | €2.09 | — |
| Jul 2026 | €2.09 | — |
| Jun 2026 | €2.09 | — |
Lowest in-stock price per month from our price history; the current month is the low so far.
How to activate your key
- Steam key — open the Steam client → Games → Activate a Product on Steam → enter the key. Stores with this activation: Steam
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All-time low so far: €1.67
System requirements
| Minimum | |
|---|---|
| OS | Microsoft® Windows® 7/8/8.1/10 (32bit/64bit) |
| Processor | Intel Core2 Duo or better |
| Memory | 4 GB RAM |
| Graphics | OpenGL 4.1 capable GPU |
| DirectX | Version 9.0 |
| Storage | 300 MB available space |
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About this game — FAQ
Can 31st prototype be played single-player?
Yes, 31st prototype is a single-player game.
What languages does 31st prototype support?
31st prototype is available in: Simplified Chinese, English, Japanese, Traditional Chinese.
FAQ
Where is the cheapest place to buy a 31st prototype key?
The cheapest 31st prototype key is currently sold by Steam for €1.67. The lowest price we have ever recorded for this game: €1.67.
How much does 31st prototype cost?
31st prototype currently costs from €1.67 — the cheapest offer across the stores we track.
Is Steam an official store or a keyshop?
Steam is an official store — keys come directly from the publisher or an authorized distributor.
Are keys from these stores legal?
Buying is legal — keys come from the grey market, so a small deactivation risk exists. So before paying, check the seller's buyer protection.
Which key region should I pick?
Global activates everywhere. Regional keys (Europe, North America, RU-CIS) only work on accounts from that region — use the Region filter to match your account.
What is an activation platform?
The service where the key activates — Steam, GOG, Epic or the publisher's platform. A key for one platform won't work on another, hence the separate filter.
What's the difference between editions?
Standard is the base game; Deluxe usually adds an expansion or bonus content. The edition filter shows exactly that variant, with no mixed prices.