Model prices and limits
Model data comes from public sources that don’t require an account:
- The OpenRouter models API, which lists hundreds of models with their prices and context lengths.
- The open-source LiteLLM model price and context-window file, maintained by its community.
- Each provider’s official pricing and model documentation pages, used to check and correct the above.
A scheduled job runs every day. It downloads the sources, normalises them into one format, and checks every record against a strict schema. If anything changed, the update is published and recorded in the history. Corrections that the automated sources get wrong go into a manually maintained overrides file, which always wins.
If a source is unavailable or returns data that fails validation, the job keeps the last good data instead of publishing something empty or broken. Every price on the site shows the date it was last checked and links to where it came from.
Token counts
Models read text as tokens. Each model family splits text differently, so the same paragraph can be a different number of tokens for different models.
- Exact counts are used where the tokenizer is public. For example, OpenAI’s tokenizers and the open-weight Llama, Mistral and Qwen tokenizers run directly in your browser.
- Estimates are used where the tokenizer isn’t public, such as recent Claude and Gemini models. They’re always labelled as estimates. Where the provider offers a free token-counting endpoint, you can get an exact count with your own API key.
Counts are for the text you enter. A real API request also uses tokens for chat formatting, system prompts and tool definitions, so your bill can be slightly higher than the count for the text alone.
Calculations
Cost calculators multiply token counts by published per-million-token prices, showing input, output and cached prices separately where providers price them differently. Hardware calculators show their formula and assumptions on the page, so you can check the working. Results don’t include taxes, discounts or free tiers unless the tool says so.
How tools are tested
The logic behind every tool is a set of small functions with automated tests. Tokenizers are checked against reference outputs for a fixed set of sample texts. Calculators are checked against hand-worked examples. Format converters and generators are checked against known-good files. The tests run before every release; if any fail, the release is blocked.
Error fixes
Every fix in the error database is reproduced and tested by hand. Each page states the tool version and the date the fix was last verified. Fixes aren’t copied from other sites.
Writing and AI assistance
Guides and explanations are written and edited by Tahir Nazir. AI assistants help build and test the tools and help draft some text, as you’d expect on a site about AI developer tools. Every page, tool and error fix is reviewed by a person before it’s published.
Prices are the exception: they update automatically every day from the sources above. Each update must pass the schema checks and the sanity checks described in model prices, and the history is spot-checked by hand. When an automated value is wrong, a manual correction is added that overrides it on every future update.
Corrections
If you spot a mistake, email hello@its-tahir.com with a link to the correct information (see what to include). Confirmed errors are fixed promptly and the page’s “last updated” date changes. Significant corrections are noted on the page.
Independence
No provider pays for placement, rankings or reviews. Comparisons are ordered by the numbers or by the sort you choose. If the site ever carries sponsored content, it will be clearly labelled as sponsored.