Free, interactive tools for teaching Computer Science & Digital Technology. No login, no install β just open and teach.
Bubble, Insertion, Selection, Merge and Quick Sort with step-through animation, custom data sets, and Big O analysis.
Build weighted graphs with drag-and-drop, watch Dijkstra's algorithm find the cheapest route step by step.
Linear and Binary search step by step. Visual array with pointers, comparison counters, and complexity analysis.
Interactive growth chart showing how O(1) through O(2βΏ) scale. Toggle complexities, see operations table.
Race two sorting algorithms head-to-head on identical data. Countdown, live bars, comparison stats, winner declared!
Base conversion with full working, binary addition, arithmetic shifts, overflow/underflow.
Calculate file sizes for bitmaps and sound files with step-by-step working. Presets for common scenarios.
Watch RLE and Huffman coding work step by step. Frequency tables, compression ratios, lossy vs lossless explained.
Type a domain and watch the full DNS resolution process animate β from browser cache to root server to IP address.
Step-by-step visualisations of 6 attack types: phishing, DDoS, MitM, SQL injection, brute force, social engineering. With defences.
Drag-and-drop network builder. Place devices, connect cables, simulate packets. 6 preset topologies with SPOF detection.
Interactive gates with toggle inputs, auto-generated truth tables, and a Boolean expression builder. AND, OR, NOT, XOR, NAND, NOR.
Write LMC assembly, watch the FDE cycle animate, see registers and 100 memory mailboxes update in real time. 5 preset programs.
Watch Python code pass through lexical analysis, parsing, semantic analysis, code gen and optimisation.
Compare FCFS, SJF, Round Robin, Priority scheduling with Gantt charts and turnaround/waiting time metrics.
Paste a Python error message, get a student-friendly explanation with causes and fix suggestions. 9 error types covered.
Convert between Python and WJEC-style pseudocode (Appendix B). Bi-directional with full reference table.
Drag scrambled code blocks into the correct order. 10 built-in problems (easyβhard) or create your own from any code.
Turn Python code into beautiful images for slides and worksheets. 8 themes (Monokai, Dracula, Nord...), line numbers, PNG export.
Write Tkinter code, see GUI render live in the browser. Download .py for IDLE.
Watch recursive call stacks build and unwind. Factorial, Fibonacci, Power, Sum β step through or auto-play.
Interactive stacks (LIFO), queues (FIFO), and linked lists with push/pop/enqueue/dequeue animations and operation logs.
Write and run real SQL in the browser. 3 databases (School, Shop, Music), 20 guided exercises, schema viewer, Ctrl+Enter to run.
Enter BNF rules, auto-generate railroad diagrams. Trace strings through syntax.