Optimization Frameworks for Tie-Oriented and Actor-Oriented Relational Event Models R package remstimate version 3.1.0 Tools for fitting, diagnosing, and analyzing tie-oriented and actor-oriented relational event models, under both frequentist and Bayesian approaches. The package supports tie-oriented modeling (Butts, 2008, <doi:10.1111/j.1467-9531.2008.00203.x>) and an actor-oriented modeling framework (Stadtfeld et al., 2017, <doi:10.15195/v4.a14>), with additional model diagnostics and goodness-of-fit tools. Interfaces to estimation backends provide a range of extensions: random-effects (frailty) relational event models capturing sender, receiver, and dyadic heterogeneity (Juozaitiene & Wit 2024, <doi:10.1007/s11336-024-09952-x>; Mulder & Hoff, 2024, <doi:10.1214/24-AOAS1885>), finite mixture and dyadic latent class models for unobserved dyadic heterogeneity (Lakdawala et al., 2026, <doi:10.1016/j.socnet.2026.06.006>), penalized estimation via the lasso, ridge, and elastic net (Tibshirani, R., 1996, <doi:10.1111/j.2517-6161.1996.tb02080.x>; Karimova et al., 2023, <doi:10.1016/j.socnet.2023.02.006>), and approximate Bayesian regularization (Karimova et al., 2025, <doi:10.1016/j.jmp.2025.102925>). Modeling of events with a duration is also supported (Lakdawala et al., 2026, <doi:10.48550/arXiv.2602.21000>) and moving window relational event models (Mulder & Leenders, 2019, <doi:10.1016/j.chaos.2018.11.027>; Meijerink et al., 2023, <doi:10.1371/journal.pone.0272309>). Software Depends: R (>= 4.0.0), remify (>= 4.1.0), remstats (>= 4.1.0) Imports: Rcpp, trust, mvnfast LinkingTo: Rcpp, RcppArmadillo, remify (>= 4.1.0) Suggests: knitr, rmarkdown, tinytest, survival, coxme, glmnet, lme4, glmmTMB, flexmix, shrinkem (>= 0.4.0), MASS, nnet, remdata (>= 0.2.1) Giuseppe Arena <g.arena@uva.nl> Comprehensive R Archive Network (CRAN) Giuseppe Arena [aut, cre] (ORCID: <https://orcid.org/0000-0001-5204-3326>), Joris Mulder [aut], Rumana Lakdawala [aut], Fabio Generoso Vieira [aut], Marlyne Meijerink-Bosman [ctb], Diana Karimova [ctb], Mahdi Shafiee Kamalabad [ctb], Roger Leenders [ctb] MIT + file LICENSE (https://CRAN.R-project.org/package=remstimate/LICENSE) 2026-07-17 application/tgz https://CRAN.R-project.org/package=remstimate doi:10.32614/CRAN.package.remstimate