Fractional Factorial Designs with Alias and Trend-Free Analysis R package MixFrac version 1.0 Constructs mixed-level and regular fractional factorial designs using coordinate-exchange optimization and automatic generator search. Design quality is evaluated with J2 and balance (H-hat) criteria, alias structures are computed via correlation-based chaining, and deterministic trend-free run orders can be produced following Coster (1993) <doi:10.1214/aos/1176349410>. Mixed-level design construction follows the NONBPA approach of Pantoja-Pacheco et al. (2021) <doi:10.3390/math9131455>. Regular fraction identification follows Guo, Simpson and Pignatiello (2007) <doi:10.1080/00224065.2007.11917691>. Alias structure computation follows Rios-Lira et al.(2021) <doi:10.3390/math9233053>. Software Imports: stats, utils Suggests: knitr, rmarkdown, testthat (>= 3.0.0) Sukanta Dash <sukanta.iasri@gmail.com> Comprehensive R Archive Network (CRAN) Sukanta Dash [aut, cre] GPL-3 2025-12-12 application/tgz https://CRAN.R-project.org/package=MixFrac doi:10.32614/CRAN.package.MixFrac