Everything in the catalog

Compares image codecs side by side and recompresses photos to smaller JPEG, WebP, AVIF or PNG files.

Online LaTeX editor with collaboration, templates and version history, so no local install is needed.

Grammar, spelling and style checker for dozens of languages, usable in the browser without installing anything.

Plain-text publishing page where you write and post a piece to a public URL, with anonymous posting.

Shows how identifiable your browser fingerprint is compared with other visitors.

Tests how well your browser blocks trackers and how unique its fingerprint looks.

Loads a website and reports ad trackers, third-party cookies, keystroke capture and session recording it finds.

Generates random multi-word passphrases and explains why passphrases beat short passwords.

Use area tiles to multiply and factor polynomials visually.

Deduce hidden balls inside a box by firing lasers in and watching where they come out.

Drag points and see the fitted line, residuals and correlation change.

Add bonds and lone pairs around a central atom to see VSEPR molecular geometry.

Stimulate a neuron and watch ion channels and the membrane potential during an action potential.

Remove groups of matching colors to clear the board and score points.

Collection of single-player logic puzzles such as Mines, Loopy and Towers.

Connect islands with bridges so each island's number matches the bridges it has.

Roll a cube around a grid to pick up blue squares without leaving any behind.

Place a full set of dominoes on a grid of numbers so each pair is used once.

Classic sliding tile puzzle: slide numbered tiles into order using one empty gap.

Fill the grid with regions so each number shows the size of the region it belongs to.

Flip squares in patterns to turn every cell to the same state.

Fill the whole grid with one color by repeatedly flooding from the corner within a move limit.

Divide the grid into symmetrical regions that each surround a dot.

Mastermind-style code-breaking game with colored pegs and feedback on each guess.