Separate outlines from packaging
TTF and OTF fonts share the OpenType table system but can store different outline technologies. TrueType glyf outlines and CFF/CFF2 outlines cannot be interchanged by changing a filename. WOFF and WOFF2 are webfont containers that can carry either supported outline type.
Choose WOFF2 for a webfont package, WOFF when a particular workflow requires it, or native output to recover the underlying .ttf or .otf. Font Bridge selects the native extension from actual tables, not from the name you uploaded.
Inspect the actual output
The conversion path reopens output bytes and compares character coverage, axes and table checksums. A full container conversion can change binary serialization while leaving the design usable; it is not automatically a byte-preserving operation.
The report records original and output SHA-256 values. If no transformation is requested and the format already matches, the original bytes are returned unchanged. Wrapper metadata and private blocks can be dropped when changing containers, so keep the original file.
Use the package deliberately
The ZIP includes the real font, a CSS @font-face rule, a local HTML sample and the change report. The CSS uses a fixed alias to avoid unsafe font metadata in CSS; it does not rename internal font records or satisfy reserved-name rules.
Adapt font-style for italic or oblique faces and test the weight/stretch ranges in your design. Include the original licence document before distributing the font. A small file is only useful if the right glyphs, layout behavior and permission accompany it.