Paste text and pick a model to see an estimated token count. Approximate, not exact: no major provider ships a small client-side tokenizer, so this blends a characters-per-token and words-per-token heuristic instead of running the model's real BPE/SentencePiece tokenizer. Expect real counts to differ by roughly ±10-20%, more for code or non-English text. Data as of August 2026 — see Context Window Calculator to check whether it fits a model's limit.
curl -sS -X POST https://devops.majbase.com/token-counter/api -H "Content-Type: application/json" -d '{"text":"Hello, world!","model":"claude-sonnet-5"}'Returns {"model", "char_count", "word_count", "estimated_tokens"}, or {"error": "..."}. Valid model ids: claude-opus-5, claude-sonnet-5, claude-haiku-4.5, gpt-5.5, gpt-5, gpt-4o, gemini-3-pro, gemini-3-flash.