Build a Tokenizer from Scratch

Crackr released a free, open-source guide on building a byte-level BPE tokenizer from scratch, culminating in a multilingual encoding compatible with OpenAI's tiktoken and a web playground. The guide includes implementing BPE, optimizing training, saving a .tiktoken model, and shipping it in a playground, with automated evaluations available on Crackr.

Build a byte-level BPE tokenizer from scratch, starting with a simple word tokenizer and working up to a trained multilingual encoding compatible with tiktoken. Along the way, you’ll implement BPE, optimize training, train your own tokenizer, save it as a .tiktoken model, and ship it in a small web playground. Live demo: See what you will build by the end of the guide https://tokenizer-playground.onrender.com/ . This repository contains the complete open-source guide. You can also build the project on Crackr https://app.crackr.dev/projects/build-your-own-tokenizer , where each step comes with automated evaluations, progress tracking, and interactive playgrounds. The full project and all evaluations are free. Scale up training /crackr-org/build-a-tokenizer-from-scratch/blob/main/guide/05-ship-your-tokenizer/01-scale-up-training.md Port your tokenizer to tiktoken /crackr-org/build-a-tokenizer-from-scratch/blob/main/guide/05-ship-your-tokenizer/02-port-your-tokenizer-to-tiktoken.md Build a tokenizer playground /crackr-org/build-a-tokenizer-from-scratch/blob/main/guide/05-ship-your-tokenizer/03-build-a-tokenizer-playground.md Where to go from here /crackr-org/build-a-tokenizer-from-scratch/blob/main/guide/05-ship-your-tokenizer/04-where-to-go-from-here.md This guide is available under the MIT License /crackr-org/build-a-tokenizer-from-scratch/blob/main/LICENSE .