Alternatives to Ghostscript
PostScript and PDF interpreter behind a great deal of other software. The listings below can replace it for an important use case. Each note says what changes if you switch.
The original
Ghostscript
PostScript and PDF interpreter behind a great deal of other software.
Replacements
Listings that take over the same core job as Ghostscript.
MuPDF
Compact, very fast PDF and XPS viewer with a command-line toolkit.
MuPDF comes from the same Artifex licensing model under AGPL-3.0, adding a fast viewer and mutool, but does not interpret PostScript or PCL.
Poppler
PDF rendering library with pdftotext, pdftoppm and pdfinfo tools.
Poppler is GPL-2.0 and provides pdftotext, pdftoppm and pdfinfo for extraction and rasterising, without PostScript interpretation or compression workflows.
mutool (MuPDF)
Command-line companion to MuPDF for PDF extraction, cleaning and merging.
mutool offers a lighter open-source command line for PDF extraction, cleaning and merging, without Ghostscript's PostScript, PCL and XPS handling.
qpdf
Command-line tool for content-preserving PDF transformations.
qpdf under Apache-2.0 rewrites PDF structure losslessly for pipelines, but does no rendering, conversion or text extraction.
pdfcpu
Go library and command line for validating and transforming PDFs.
pdfcpu is an Apache-2.0 single static binary and Go library for validating and transforming PDFs, without rendering or PostScript support.
Also worth comparing
These listings name Ghostscript as their own alternative, so the relationship runs both ways.
Cpdf
Command-line PDF toolkit covering split, merge, stamp and encrypt.
Ghostscript is AGPL-3.0 open source and focuses on PDF conversion and compression, with a cryptic option set and paid licences for commercial redistribution.
Similar software
Related functionality, not a direct replacement.
Sumatra PDF
A small, fast, open-source reader for PDF, EPUB, MOBI, CBZ, DjVu and other documents on Windows.
PDFtk Server
Command-line PDF toolkit for merging, splitting and stamping.
Tesseract OCR
The open-source OCR engine behind most free text recognition tools.
Evince
GNOME's lightweight document viewer for PDF, PostScript and other document formats on Linux.
