🔤 Font Forensics
Inspect OpenType and SFNT fonts down to their tables, mappings, metrics, glyph geometry, layout data, hinting programs, metadata, fingerprints, and raw bytes.
This tool is client-side only. Everything happens in your browser and none of your data is shared.
Overview
Proof Sheet
This uses the browser's font renderer independently of the binary parser. A font can render while containing structural oddities, and a structurally readable font can still fail to render.
Table Directory
SFNT/OpenType fonts are directories of tagged binary tables. Checksums are recalculated from the table bytes; the special head checksum adjustment is handled separately.
Naming & Metadata
The name table can contain several records for the same conceptual field across platforms, encodings, and languages. Those records are shown separately instead of being collapsed into a single value.
Metrics & OS/2 Autopsy
Unicode / cmap Laboratory
Characters do not point directly at outlines. A cmap subtable maps Unicode code points to glyph IDs, and several subtables can coexist or disagree.
Glyph Explorer
Glyph Microscope
For TrueType glyf outlines, contours and quadratic on/off-curve points are decoded directly from the file. Composite glyphs are identified and their component references are listed.
OpenType Layout & Variation Inventory
This inventories layout and variation tables and their feature tags. It does not execute GSUB/GPOS shaping or variation deltas.
Variable Font Laboratory
The fvar table defines design axes and named instances. These values are decoded from the table rather than inferred from filenames.
Layout Lookup Archaeology
Feature tags are only the index. This view follows GSUB/GPOS FeatureList records to their lookup indices and inventories lookup types and subtable counts without acting as a shaping engine.
TrueType Programs & Hinting
TrueType hinting is a small stack-machine program. This view inventories fpgm, prep, cvt , and glyph instruction bytes and provides a conservative opcode disassembly. Instructions are never executed.
CFF / CFF2 Anatomy
CFF-flavored OpenType fonts store PostScript-style charstrings rather than glyf contours. This view exposes CFF headers and INDEX structures without executing Type 2 charstrings.
Metadata Lab & Presets
Raw byte edits and serialized name-table edits are kept as separate editing paths. Serialized records may grow, shrink, be deleted, or be added; rebuilding regenerates offsets and checksums.
Whitespace & Typography Inventory
Anomalies & Integrity
Printable Strings
Readable byte runs can reveal vendor strings, URLs, version information, private-table clues, and other debris. A string shows that those bytes exist; it does not establish provenance.
Hashes & Fingerprints
Hex Microscope / Editor
Selecting a table or glyph can jump to its raw bytes. Selecting a byte reports the narrowest recognized owner. Raw edits are staged in memory and can make the font invalid; nothing is silently repaired.
Pending Changes
Raw byte edits are staged against a working copy of the original font. Serialized metadata edits remain in the independent name-table model until a rebuilt font is created.
Export
Raw staged export writes byte edits literally. Serialized rebuild reconstructs the SFNT table directory and name table, permits variable-length metadata, realigns tables, recalculates table checksums and head.checkSumAdjustment, and reparses the result before enabling download.
About This Tool
Font Forensics is an OpenType and TrueType font analysis tool for inspecting the internal structure of TTF, OTF, WOFF, and WOFF2 files. It reads SFNT tables, naming records, Unicode mappings, metrics, glyph data, layout tables, hashes, printable strings, and raw bytes.
The table directory shows each OpenType table with its offset, length, stored checksum, and calculated checksum. The naming and metadata views expose individual name records instead of collapsing platform, encoding, and language variants into a single value.
Glyph inspection covers Unicode cmap mappings, horizontal metrics, TrueType glyf outlines, composite glyph references, variable-font axes, OpenType layout features, hinting programs, and CFF or CFF2 structure where available. A proof sheet uses the browser renderer as a separate visual check against the binary parser.
Font Forensics also includes anomaly checks, SHA-256 fingerprints, printable strings, metadata editing, checksum repair, and a hex editor for direct byte inspection. Rebuilt fonts are reparsed and verified before download when the serializer supports the requested changes.