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Generate sample datasets from the terminal — or fetch real-world rows from APIs and public sources. Useful for tests, demos, prototypes, and quick data pulls.

Natural language

Synthetic (default)

Real-world sources

Phrases with real, actual, live, world bank, pubmed papers, or a URL route to real fetchers. Fake / sample / mock keep synthetic generation.

CLI commands

Real-world sources

Real sources cap at 500 rows. When --source is set, Arka never falls back to synthetic or LLM data — fetch errors are reported clearly.

World Bank indicators

gdp, gdp_per_capita, population, life_expectancy, co2, unemployment, internet Country codes use ISO-3166 alpha-2 (e.g. IN, US). Natural language country names (India, United States) are parsed automatically.

Supported formats

csv, json, jsonl, tsv, yaml, xml, sql, markdown, xlsx XLSX output requires openpyxl (pip install openpyxl). For richer fake values, install the optional Faker extra:

Presets

Built-in presets infer columns automatically (synthetic mode only): Field names are matched to generators (names, emails, phones, addresses, dates, numbers, UUIDs, booleans). Use --llm for complex custom schemas when an LLM API key is configured.

Output

Print to stdout by default, or save with -o output.csv or by passing a filename as the first argument.