EXP File

.exp is Melco's proprietary machine-embroidery stitch format, used to transfer digitized designs to Melco commercial and semi-commercial embroidery machines. The file stores stitch data in a compact binary structure: each stitch is encoded as a pair of signed bytes representing relative X and Y movements from the previous needle position. Special byte patterns within the same stitch stream serve as control codes for jump stitches, thread trims, color stops, and end-of-design markers.

A defining characteristic of .exp is that it contains no thread color information. Colors must be tracked separately - typically in a companion .exd file or via a manually maintained color sequence in the embroidery software. The file also has no standard header or magic bytes, so it cannot be reliably identified by its binary signature alone; file source and naming convention are the practical identifiers.

.exp is closely related to other stitch-level formats such as .DST (Tajima) and .PES (Brother), all of which encode primitive needle-position offsets rather than high-level embroidery objects. Converters such as Embird and Wilcom TrueSizer can read, write, and convert .exp files across most embroidery platforms. The format also appears in the Bernina software ecosystem. Being raw uncompressed binary, .exp files are straightforward to parse and are supported by open-source embroidery tools such as the libembroidery library and the Ink/Stitch Inkscape extension.