AI tools
Count tokens, check context fit, estimate API costs, format fine-tuning files, and read chat exports. Exact where an OpenAI tokenizer exists, labeled estimates where one doesn't. Everything runs in your browser; exports never leave the tab.
9 tools
- Tokenizer playground
Count and inspect OpenAI tokens (o200k, cl100k, p50k, r50k) in a worker.
- Context fit
Does your prompt fit? Exact OpenAI counts; labeled estimates for any other model.
- API cost estimator
What a prompt costs to run: dated price data, exact arithmetic, tiers applied.
- Fine-tune JSONL formatter
Validate and format training files: target presets, per-line errors, loss ledger.
- Chat export viewer
Read a ChatGPT export or JSONL log. Virtualized, local, nothing sent anywhere.
- Chat template renderer
Render a transcript to ChatML, Llama, Mistral, or Gemma format, with token counts.
- Model comparison
The dated model registry as a table: context, output ceiling, rates, long tiers, tokenizer status.
- Vision token cost
Image tokens by documented tile/area rules, costed exactly. Versioned formulas, custom rates, no vendor calls.
- Prompt diff
Before/after prompts with exact token deltas, a line diff, and the cost change per model.
Your files are processed on your device. The few tools that talk to the internet say so before they do.