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402utils Token Counter (BPE/tiktoken)
x402
402utils Token Counter (BPE/tiktoken) is a paid API for AI agents from 402utils.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-10).
Counts BPE tokens in a given text using tiktoken with o200k_base or cl100k_base encoding, returning token count, character count, and encoding used
Price / call$0.001
Success—
StatusUnknown
How this service works
Count BPE tokens in a text with tiktoken (o200k_base = GPT-4o default, or cl100k_base). An agent can check content fits an LLM context window before paying for an expensive call. Returns token count, char count and encoding. Honest scope: an OpenAI-style estimate — no open-source Claude tokenizer exists (exact Claude counts need the Anthropic API), Gemini differs too. Provided text only; nothing is fetched. Max 1 MB.
Output
Returns a JSON object containing the integer token count for the provided text, the character count, and the encoding name used (o200k_base or cl100k_base). This lets the agent determine whether content fits within a model's context limit before making a costly LLM API call.
Example use cases
Example prompt
“Before I send this 10-page legal document to GPT-4o, can you count how many BPE tokens it contains using the o200k_base encoding so I know if it fits in the context window?”
Technical details
Endpoint
POSThttps://402utils.com/v1/token-count?utm_source=zero.xyzWhen to prefer
Use this endpoint when an agent needs a fast, cheap pre-flight check before calling an OpenAI GPT-4o, GPT-4, GPT-3.5, or embedding model API to ensure the input fits the context window and to estimate token-based costs. Prefer o200k_base for GPT-4o/GPT-4.1/o-series and cl100k_base for GPT-3.5/GPT-4/text-embedding-3. Note: this gives OpenAI-style estimates only — it is not exact for Claude or Gemini tokenization.
Side effects
- Text exceeds 1 MB UTF-8 limit — returns error indicating size constraint
- Invalid encoding value supplied — returns validation error for the enum field
- Empty POST body or missing text field — may return 0 tokens or a validation error
- Network/payment failure — x402 payment of $0.001 USDC required; insufficient funds or wallet misconfiguration cause 402 error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| text | string | The text to tokenize (may be empty → 0 tokens; max 1 MB UTF-8). |
| encoding | string | tiktoken encoding. o200k_base = GPT-4o / GPT-4.1 / o-series (current standard); cl100k_base = GPT-3.5/4, text-embedding-3. |
Tags
x402
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