tiktoken is a fast BPE tokeniser for use with OpenAI's models.
const tiktoken = require('tiktoken-node')
let enc = tiktoken.getEncoding("gpt2")
console.assert(enc.decode(enc.encode("hello world")) == "hello world")
// To get the tokeniser corresponding to a specific model in the OpenAI API:
enc = tiktoken.encodingForModel("text-davinci-003")The open source version of tiktoken-node can be installed from npm:
npm install tiktoken-node