Developer tools
Small, client-side utilities for upload QA — size math, MIME reference, and magic-byte hints. Everything runs in your browser; pair them with the dummy file generator and scenario playbooks.
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File size calculator
Convert MB to bytes, KB, and GB. Binary (1024) and decimal (1000) bases with upload-limit presets.
Open tool →MIME type lookup
Extension → MIME and reverse lookup for multipart uploads and Content-Type validation.
Open tool →Magic-byte sniffer
Inspect file signatures from a local sample or hex dump — offline, no upload.
Open tool →How these tools fit together
- File size calculator — translate “5 MB” into exact bytes before you generate a boundary fixture.
- MIME lookup — confirm expected
Content-Typevalues in API docs and test plans. - Magic-byte sniffer — verify what is actually inside a file when extensions lie.
For end-to-end upload checklists, see our file upload testing guide.