lz78 online calculator

Purpose-built tool for exploring LZ78 dictionary-based compression. It encodes input text into a sequence of codewords by constructing a dynamic dictionary of previously seen substrings and emitting the match index plus the next character.
Conceptually, encoding proceeds by scanning the input to locate the longest substring already present in the dictionary, emitting a codeword consisting of the matched dictionary index and the immediately following character, then inserting the new substring into the dictionary. Decoding reverses this process to reconstruct the original text from codewords. The tool supports teaching, verification, and lightweight testing by exposing the core mechanics in a clean, auditable form without UI distractions.
Intended users include software engineers, educators, and learners who want to see how dictionary growth influences codeword count and to compare behavior across inputs. It is language-agnostic and relies on UTF-8 text, making it suitable for classroom demonstrations or script-based experiments. A key differentiator is its focus on algorithmic transparency and the option to export encoded or decoded representations for analysis or benchmarking.