dCode
dcode.fr
A large set of tools for solving ciphers, codes, puzzles, number problems and games, with explanations of how each method works.
Why it is useful
A treasure for puzzle hunters, geocachers and escape-room fans. It identifies many ciphers and shows how to decode them, so you learn as you go.
More in Hidden Websites
Other hidden websites you might not have heard of.
- cryptiiA modular tool for converting, encoding and decoding text, where you chain together steps such as Base64, Caesar cipher and binary.
- MetaculusA forecasting community where users predict the probability of future events — from elections to AI milestones — and track their own accuracy over time.
- NautilusA science and culture magazine organized around themes, publishing interconnected articles across biology, physics, psychology, and philosophy each issue.
- Neal.funCollection of interactive web experiments and games by developer Neal Agarwal.
- Wiby SearchSearch engine for the old web — indexes only simple, hand-crafted websites without JavaScript or tracking.
- Vintage EverydayA large collection of vintage photographs and curiosities from the 19th and 20th centuries, with themed posts on fashion, travel, people and daily life.