Isaac Codex
Find it
No name? Start with a picture.
Choose a photo or use the camera. Check the match and open the entry, without needing to know what the item is called.
Free · Recognition stays on your device
How item identification works
Find items.Meet the cast.Talk builds.
20 languages. An offline encyclopedia. AI answers.
LESS GUESSING. MORE PLAYING.
One more room. A little more prepared.
Understand it
The details that make a difference.
Effects, item pools, unlocks and interactions. Search by name, color or category. Download your language pack and keep it all offline.
Free · Available offline after download
Explore the player guidesTalk it through
“But what about my build?”
Bring your items and your question. Explore an interaction, ask a follow-up, and check the sources before making your next move.
Online AI · Subscription and usage limits apply
Read about AI and privacyInside Isaac Codex
Beyond the item pedestal.
Get to know the characters. Keep track of the route. Bring your next question.
Meet the cast
Check starting stats, unlock conditions and the details that make each character different.
Think a step ahead
Bring your current items and ask a follow-up before committing to a risky choice.
Find your route
Choose your destination. Check the requirements and the next step along the way.
App Store artwork featuring the app. AI examples may use localized layouts; answers can be mistaken.
THE FIELD NOTES
A little knowledge. A better next move.
ITEM IDENTIFICATION
How to identify an Isaac item without its name
Follow one real image from recognition to the item entry, with a color-filter fallback when a photo is not enough.
Read guide
SACRIFICE ROOMS
Sacrifice Room: should you take one more hit?
The next reward, the next danger, and when to step away from the spikes.
Read guideDICE ROOMS
Dice Rooms: what do the 1–6 pips change?
Know what gets rerolled before you step on the die.
Read guide ITEM IDENTIFICATION
Brimstone or Mom's Knife?
One Devil Room, two strong items: check the heart cost, your position in a fight, and what happens if you buy both.
Read guideTry the quick reference
Count the dots. Know the change.
Choose the number on the floor before you step onto the die.
Repentance / Repentance+ · Each Dice Room activates once.
Your build
Rerolls the active and passive items you’re carrying. In co-op, affects the player who steps on the die.
Your current build can change.Room pickups
Rerolls pickups in this room. Your carried items are not the target.
This room, not the entire floor.Floor pickups
Rerolls floor pickups and trinkets, including shop pickups. Devil/Angel Rooms, Black Markets and Crawl Spaces are excluded.
Loose pickups and trinkets, not your held build.Item pedestals
Rerolls item pedestals across the floor. Devil/Angel Rooms, Libraries, Black Markets and Crawl Spaces are excluded.
Items on pedestals, not items already collected.Restart floor
Rerolls and restarts the current floor. Finish anything you still want to do before stepping on it.
You are restarting this floor.Several rerolls
Combines the 1-, 3- and 4-pip effects, including their exclusions. In co-op, every player’s held items are rerolled.
Your build and floor contents can change.FAQ
Before your next run.
What is free?
The encyclopedia and item identification are free. AI questions have a separate subscription and usage allowance. Current prices and terms appear in the app before purchase.
Does it work offline?
Downloaded encyclopedia content and on-device identification work offline. Some languages need an initial content-pack download. AI questions require an internet connection.
Are my photos uploaded?
Item identification runs on your device. Images you explicitly attach to an AI conversation use a separate online service; review the privacy information before sending.
Which languages does the app support?
English, Simplified and Traditional Chinese, Russian, Spanish, Latin American Spanish, Brazilian Portuguese, Polish, Korean, French, German, Japanese, Italian, Turkish, Ukrainian, Czech, Dutch, Finnish, Swedish and Hungarian.
Is this an official app?
No. Isaac Codex is an unofficial personal fan project. Game names and artwork belong to their respective owners.
YOUR NEXT RUN, WITH COMPANY
Take the guide into your next run.
Open the store directly, or scan the QR code to continue on your phone.