LilyPond is an automated engraving system. LilyPond formats music beautifully and automatically and has a friendly syntax for its input files. It is Free Software ("open source").

Here are some key features of "LilyPond":

Music language input:

· The input is done in the form of a textual music language.

· Entry may be done with the text editor of your choice, and using the national language of your choice.
· The ASCII input language can integrate with TeX, HTML and Texinfo, thus allowing musicological treatises to be written from a single source.
· The music and its layout are strictly separated, so score and parts (possibly in different styles and keys) and scores can be generated from the same source, and changes always take effect in both places.
· The output can be improved by upgrading the program.
· Pieces can be printed in different (typographical) house styles, or according to different notational conventions.

Automated high-quality formatting:

· Automatic spacing, line breaking and page breaking.
· Handling of polyphonic collisions for notes, dots, and rests.
· Automatic placement of accidentals, beams, slurs.
· Users don't need typographical expertise to produce good notation.
· No user interaction necessary during running, Running the program can be automated, which is convenient for mass converting databases of digitized music, and printing algorithmic compositions.
· The Feta font has been tailored especially for LilyPond, and was designed carefully mimicking the finest hand-engraved scores. It is available as a scalable font, but also as a Metafont.
· Support for many notation constructs.

Special notation:

· Chord names.
· Drum notation.
· Figured bass.
· Grace notes.
· Fret diagrams.
· Basic tablature notation.
· Cluster notation and rhythmic grouping signs.
· Tremolos, both for single notes and chords.
· Tuplets in arbitrary ratios.
· Polymetric notation.
· Mensural notation.
· Automatic cue-notes,.
· Automatic part combining for orchestral scores.
· Quarter tone accidentals.
· Ambituses.
· Metronome markings.
· Harmonics.
· Measure repeats (�Percent style�).
· EasyNotation note heads.
· Blanking arbitrary notation elements.
· Arpeggio signs.
· Ottava brackets.
· Nested analysis brackets.
· Piano pedals.
· Starting and stopping staves anywhere
· System separators

Robust design:

· Lyrics in any language.
· Output in PostScript, PDF, PNG, MIDI, SVG.
· No limits on the number of staves, voices, measures, lengths of texts, etc.
· Extensible with built-in LISP interpreter.

Excellent support:

· Runs on Unix, including MacOS X and Linux, and Windows.
· Active user community.
· Extensive documentation.
· Supported by many other programs,
· RoseGarden NoteEdit and PowerTab and Denemo. Imports ABC, ETF and MIDI.