Tool
Font Inspector
This font inspector runs in your browser. Drop a woff2, woff, ttf, or otf file and we read its format from the magic bytes, render a live preview with the FontFace API, and show a glyph grid of the basic ASCII range. The file never leaves your machine.
For deep inspection of OpenType tables, axes, named instances, and language coverage, we point you to Wakamai Fondue. The browser can render fonts and read basic metadata; it cannot safely decode every OpenType table without a parser library.
Drop a font file here
or . Supports .woff, .woff2, .ttf, and .otf.
Your font file never leaves your browser. No upload, no server.
Want to see every OpenType table, axis, and named instance in this font? Open Wakamai Fondue and drop the same file. Upload a font file and instantly see what it can do, every OpenType feature, axis, and language it supports.
Built with the variable font tester and the rest of the Font Blend toolkit.
How Font Inspection Works
A font file is a binary table of contents. Each table holds one piece of metadata: the family name, the glyph outlines, the kerning pairs, the OpenType features, the variable-font axes. Reading the full set of tables safely in the browser would mean shipping a parser the size of a small app. We chose not to.
Need the full breakdown? Open Wakamai Fondue and drop the same file. It runs in the browser too, with a purpose-built parser that lists every table the font ships.
What the Inspector Reveals
The basic inspector shows you what the browser can read without a dedicated parser. This is enough to answer most practical questions about a font file.
- Format
- The format is detected from the first four bytes of the file. WOFF2 uses Brotli compression and is typically the smallest format. WOFF uses Zlib. OTF is OpenType with CFF outlines, and TTF is TrueType outlines. The format affects browser support: WOFF2 has universal modern support, WOFF works everywhere, and OTF and TTF are the fallback formats for older browsers.
- Glyph preview
- The FontFace API renders the uploaded font in the browser, so the preview shows exactly how the font looks on your system. Edit the preview text to test specific letter combinations, punctuation, or the full alphabet. The rendering is driven by the FontFace API, not an image, so it matches what the browser will display in the actual page.
- Glyph grid
- The grid shows every glyph in the ASCII range that the browser can enumerate. This tells you whether the font includes the characters you need, but it does not show all the glyphs in the file. Some fonts include thousands of glyphs across multiple scripts that the browser enumeration cannot list without a table parser.
- Axes and named instances
- If the font is variable, the inspector reads the axis ranges from the FontFace API. It shows the tag, the minimum, the maximum, and the default value for each axis. Named instances, predefined combinations of axis values like "Bold" or "Light Condensed", appear when the API exposes them.
When to Use the Font Inspector
The inspector answers three questions that come up regularly when working with web typography.
- Which characters does this font include? Upload the file and check the glyph grid for the specific characters you need. For non-ASCII characters like accented letters, Cyrillic, or Greek, look for a font that explicitly lists that script coverage. The basic glyph enumeration here shows the ASCII range; for the full character coverage you need a deeper tool.
- Is this font variable? Upload the file and look at the axes panel. If it shows weight, width, optical size, or slant axes, the font is variable. If it shows no axes, it is a static font. This tells you whether you can use font-variation-settings to drive it.
- What weights does this static font include? Upload the file and look at the named instances. If the font has predefined weights like Bold or SemiBold as named instances, those are the available static styles. A static font without named instances still has weights, but you have to infer them from the font filename or the OS font picker.
- Is this file the format I think it is? Rename a font file and you cannot tell WOFF2 from TTF just by looking at the extension. Drop it in the inspector and the magic bytes reveal the actual format. Mismatched formats cause failures in some browsers, so verifying the format before deploying is worth doing.
Frequently Asked Questions
- What is the difference between OTF and TTF?
- OTF uses CFF (Compact Font Format) outlines, while TTF uses TrueType outlines. CFF outlines tend to be slightly smaller file size, and OTF supports more advanced OpenType features like glyph substitution rules. TTF has broader historical support, especially on older operating systems. For web use, both formats work in modern browsers, and the difference is rarely noticeable in practice.
- Why does the glyph grid show fewer glyphs than the file should have?
- The FontFace API can enumerate glyphs only for the basic text plane by default. A font with extensive language support, like Noto Sans, may contain thousands of glyphs across many scripts that the browser does not enumerate through the basic API. The inspector shows the glyphs the browser can reach. For a full glyph inventory, use Wakamai Fondue.
- Can I inspect a font without downloading it first?
- No. The file must be on your local machine to drop it into the inspector. The browser cannot read font files from remote URLs without downloading them first. If you have a URL for a font file, download it and then drop it into the inspector.
- Is it safe to upload a font file?
- The file stays entirely in your browser. No bytes are sent to any server. The FontFace API reads the ArrayBuffer locally and renders glyphs in the browser rendering engine. Close the tab and the buffer is cleared from memory.
Privacy note. Your font file never leaves your browser. No upload, no server. The FontFace API keeps the buffer in memory and renders glyphs locally. Close the tab and the file is gone.