Getting Started with Tiktokenizer

Access Tiktokenizer in your browser, explore the interface, select tokenizers, and understand the color-coded token visualization. No account or installation needed.

Accessing Tiktokenizer

Tiktokenizer is a completely free web-based tool. Simply open your browser and navigate to:

https://tiktokenizer.vercel.app

No account creation, no sign-up, no installation required. The tool runs entirely in your browser.

Interface Overview

When you open Tiktokenizer, you will see a clean interface with these key elements:

1. Tokenizer Selector

   A dropdown at the top lets you choose which tokenizer to use. Different models use different tokenizers, so select the one that matches the model you are working with.

2. Text Input Area

   A large text area where you paste or type the text you want to tokenize. The tokenization updates in real-time as you type.

3. Token Visualization

   Below the input area, your text is displayed with each token highlighted in a different alternating color. This lets you see exactly where token boundaries fall.

4. Token Count

   A counter shows the total number of tokens in your text, updating live as you type or edit.

Selecting a Tokenizer

Choosing the right tokenizer is important because the same text produces different token counts with different tokenizers. Here are the main options:

Your First Tokenization

Let's try a simple exercise:

1. Open Tiktokenizer

   Go to tiktokenizer.vercel.app in your browser.

2. Select o200k_base

   Choose the o200k_base tokenizer from the dropdown (this is used by GPT-4o).

3. Paste This Text

   Type or paste: Hello, how are you doing today?

4. Observe the Results

   You should see the text split into approximately 8 tokens, each highlighted in alternating colors. Notice how spaces are sometimes attached to the beginning of words.

Understanding the Color-Coded Display

Tiktokenizer uses alternating background colors to show where one token ends and the next begins:

• Each contiguous block of the same color represents one token.
• Colors alternate between tokens so you can easily see the boundaries.
• A single character in its own color block means it is its own token (common for punctuation).
• A long word in one color block means the entire word is a single token.
• A word split across two color blocks means it was split into multiple tokens.

# The word "unbelievable" might appear as:
[un][believ][able]  ← 3 tokens, 3 different colors

# While "the" appears as:
[the]  ← 1 token, 1 color block

Comparing Tokenizers Side by Side

One of the most valuable exercises is comparing how different tokenizers handle the same text:

1. Open Tiktokenizer in two browser tabs.
2. Paste the same text in both.
3. Select o200k_base in one tab and cl100k_base in the other.
4. Compare the token counts and how the text is split differently.

You will often find that o200k_base produces fewer tokens for the same text, especially for code and non-English content. This is because it has a larger vocabulary (200K vs 100K tokens), allowing it to represent more common patterns as single tokens.