User Guide

Introduction (OTT) relies on information about a font from the uploaded Adobe Font Metrics file (.afm). It uses this information to generate OenType features and render them in a features file (.fea) you can download and import with your font development software of choice.


  1. Create new font in FontLab Studio or other font development software capable of exporting AFM files and importing OpenType feature files.
  2. Add glyphs to your font for any OpenType features you want to support. Follow the naming conventions shown below to name these glyphs.
  3. Export information about your font in Adobe Font Metrics format and upload the AFM file to to create a new project.
  4. Once you have created your project, feel free to explore the generated glyph classes and features, then export the features.
  5. Save the features file and import it into your font development software.

Glyph Naming Conventions

In order to have a glyph included in a feature, make sure you name the glyph with an appropriate suffix or ending. For example, to have your small capital glyphs used as replacements for lowercase letters in the smcp feature, name your glyphs a.smcp, b.smcp, c.smcp, etc. Suffixes containing multiple feature tags are supported and processed as best as possible. For example, a glyph named R_A.dlig.swsh would generate a rule under the swsh feature to substitute it for R_A.dlig as well as a rule under the dlig feature to substitute it for R.swash A. The table below shows what suffixes and endings are recognized by the system and used in generating OpenType features.

Please note that not all OpenType features are supported, and some that are may not generate as expected. It's important to review the features that are generated and test your font features back in the font development tool.

Feature Name/Description Feature Tag Glyph Suffixes Glyph Endings
All Alternates aalt N/A N/A
Numerator numr numr, numerator numerator
Alternative Fractions afrc afrc
Fractions frac frac
Denominator dnom dnom, denominator denominator
Superscript sups sups, superior superior
Ordinals ordn ordn
Scientific Inferiors sinf sinf
Subscript subs subs
Slashed Zero zero zero, slash, slashed
Capitals to Small Caps c2sc c2sc
Capitals to Petite Caps c2pc c2pc
Oldstyle Figures onum onum, os, osf, oldstyle oldstyle
Case-Sensitive Forms case case
Lining Figures lnum lnum
Proportional Figures pnum pnum
Tabular Figures tnum tnum
Small Capitals smcp smcp, sc, small small, smallcap
Petite Caps pcap pcap
Capital Spacing cpsp cpsp
Swash swsh swsh, swash
Titling Alternates titl titl, titling titling
Stylistic Set 01 ss01 ss01, alt1, alt01, 1
Stylistic Set 02 ss02 ss02, alt2, alt02, 2
Stylistic Set 03 ss03 ss03, alt3, alt03, 3
Stylistic Set 04 ss04 ss04, alt4, alt04, 4
Stylistic Set 05 ss05 ss05, alt5, alt05, 5
Stylistic Set 06 ss06 ss06, alt6, alt06, 6
Stylistic Set 07 ss07 ss07, alt7, alt07, 7
Stylistic Set 08 ss08 ss08, alt8, alt08, 8
Stylistic Set 09 ss09 ss09, alt9, alt09, 9
Stylistic Set 10 - 20 (same as above but with incrementally increasing number) ss10 - ss20 ss10 - ss20, alt10 - alt20, 10 - 20
Stylistic Alternates salt salt, alt, alternate alternate
Historical Forms hist hist, historical
Initial Form init init, initial
Terminal Forms fina fina, fin, final
Contextual Swash cswh cswh
Contextual Alternates calt calt
Ornaments ornm ornm
Required Ligatures rlig rlig
Contextual Ligatures clig clig
Standard Ligatures liga liga, lig
Discretionary Ligatures dlig dlig
Historical Ligatures hlig hlig