Practical, token-wise decisions for AI APIs

Practical answers for developers using commercial AI APIs

Compare model pricing, shrink your prompts, migrate providers, and stay ahead of deprecations — straight, tested answers for OpenAI, Anthropic, Google Gemini, Mistral, and DeepSeek. No fluff, real code.

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Free interactive tools

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Tokens

Token counter

Paste text, pick a model, and see exact tokens, characters, and chars/token — every token as a colored chip with its ID.

 Cost

LLM API cost calculator

Real token counts → dollar cost, split into input vs output, for the model you pick. Paste text to auto-count input.

 Cost

Model cost comparison

One prompt + expected output length, costed side by side across every model in a sortable table.

 Tokens

Tokenizer visualizer

See exactly how text splits into tokens, color-coded, with hover to inspect each token's ID and boundaries.

 Tokens

Context window checker

Paste a prompt, pick a model, and find out whether it fits the context window — and how many tokens are left.

 Tokens

Word ↔ token estimator

Quick two-way converter between word count and token count, with real-tokenizer calibration.

 Explainer

From prompt to output

A clickable pipeline explaining how an LLM turns your prompt into output — tokenization, embeddings, transformer, sampling, and back.

 Cost

AI API cost calculator (monthly)

Compare monthly spend across the latest OpenAI, Anthropic, Gemini, and DeepSeek models for your request volume — cheapest highlighted instantly.

 Tokens

JSON → TOON converter

Cut LLM token usage 30–60% by converting JSON to TOON, with live token and dollar savings. Runs in your browser.

 Tokens

TOON → JSON converter

Decode TOON (Token-Oriented Object Notation) back into standard, pretty-printed JSON. Handles tabular arrays and nesting.

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Pricing

Pricing & calculators

Per-token pricing, head-to-head cost comparisons, and calculators so you spend tokens — and dollars — wisely.

 Migrations

Migration guides

Provider-to-provider migration playbooks: API mapping, gotchas, and copy-paste code to switch with confidence.

 Deprecations

Model deprecation tracker

Which models are sunsetting, when, and what to move to. Stay ahead of breaking changes before they break you.

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