File extensions

A catch-all extension for raw binary data — firmware images, disk images, ROMs, memory dumps, and so on.

A plain-text tabular format with comma-separated fields. The lowest-common-denominator for exchanging tables between spreadsheets, databases, and scripts.

A catch-all extension meaning 'some kind of data'. Game saves, email TNEF, app logs — all hide behind `.dat`.

A file of environment variables loaded at app startup. The `.env` convention is universal in modern development for API keys and DB URLs.

A classic key-value configuration format. Still common in Windows apps and legacy Unix tools for profiles and settings.

A lightweight data-interchange format. The de-facto standard for config files, API payloads, and database dumps.

A self-contained relational database in a single file. Embedded in iOS, Android, and browsers — the de-facto standard for mobile local storage.

A configuration-focused data format with unambiguous syntax. Adopted by Rust's Cargo and Python packaging (pyproject.toml).

A tag-based markup for structured data. Still everywhere — configs, RSS feeds, SOAP APIs, and Office Open XML packages.

A human-friendly data format. Ubiquitous in CI/CD, Kubernetes, Docker Compose, and modern configuration files.