diff --git a/NAMESPACE b/NAMESPACE
index 8a971a5..51a2c55 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -2,8 +2,8 @@
 
 export(Rush)
 export(RushWorker)
-export(fun_heartbeat)
 export(get_hostname)
+export(heartbeat)
 export(rsh)
 export(rush_available)
 export(rush_config)
diff --git a/R/Rush.R b/R/Rush.R
index f4544a4..04e4827 100644
--- a/R/Rush.R
+++ b/R/Rush.R
@@ -159,6 +159,8 @@ Rush = R6::R6Class("Rush",
     #' Start workers locally with `processx`.
     #' The [processx::process] are stored in `$processes`.
     #' Alternatively, use `$create_worker_script()` to create a script for starting workers on remote machines.
+    #' By default, [worker_loop_default()] is used as worker loop.
+    #' This function takes the arguments `fun` and optionally `constants` which are passed in `...`.
     #'
     #' @param n_workers (`integer(1)`)\cr
     #' Number of workers to be started.
diff --git a/R/RushWorker.R b/R/RushWorker.R
index b54aad9..d0f7041 100644
--- a/R/RushWorker.R
+++ b/R/RushWorker.R
@@ -60,7 +60,7 @@ RushWorker = R6::R6Class("RushWorker",
           heartbeat_expire = heartbeat_expire,
           pid = Sys.getpid()
         )
-        self$heartbeat = callr::r_bg(fun_heartbeat, args = heartbeat_args, supervise = TRUE)
+        self$heartbeat = callr::r_bg(heartbeat, args = heartbeat_args, supervise = TRUE)
 
         # wait until heartbeat process is able to work
         Sys.sleep(1)
diff --git a/R/heartbeat_loops.R b/R/heartbeat_loops.R
index 8768f87..198c196 100644
--- a/R/heartbeat_loops.R
+++ b/R/heartbeat_loops.R
@@ -15,7 +15,7 @@
 #' @template param_heartbeat_expire
 #'
 #' @export
-fun_heartbeat = function(network_id, config, worker_id, heartbeat_period, heartbeat_expire, pid) {
+heartbeat = function(network_id, config, worker_id, heartbeat_period, heartbeat_expire, pid) {
   r = redux::hiredis(config)
   worker_id_key = sprintf("%s:%s", network_id, worker_id)
   heartbeat_key = sprintf("%s:%s:heartbeat", network_id, worker_id)
diff --git a/R/worker_loops.R b/R/worker_loops.R
index ae0b7f7..b1064e8 100644
--- a/R/worker_loops.R
+++ b/R/worker_loops.R
@@ -7,18 +7,21 @@
 #'
 #' @param fun (`function`)\cr
 #' Function to be executed.
+#' @param constants (`list`)\cr
+#' List of constants passed to `fun`.
 #' @param rush ([RushWorker])\cr
 #' Rush worker instance.
 #'
 #' @export
-worker_loop_default = function(fun, rush) {
+worker_loop_default = function(fun, constants = NULL, rush) {
   assert_function(fun)
+  assert_list(constants, null.ok = TRUE, names = "named")
 
   while(!rush$terminated) {
     task = rush$pop_task()
     if (!is.null(task)) {
       tryCatch({
-        ys = mlr3misc::invoke(fun, .args = task$xs)
+        ys = mlr3misc::invoke(fun, .args = c(task$xs, constants))
         rush$push_results(task$key, yss = list(ys))
       }, error = function(e) {
         condition = list(message = e$message)
diff --git a/man/Rush.Rd b/man/Rush.Rd
index 1bc86f1..f06adea 100644
--- a/man/Rush.Rd
+++ b/man/Rush.Rd
@@ -302,6 +302,8 @@ Print method.
 Start workers locally with \code{processx}.
 The \link[processx:process]{processx::process} are stored in \verb{$processes}.
 Alternatively, use \verb{$create_worker_script()} to create a script for starting workers on remote machines.
+By default, \code{\link[=worker_loop_default]{worker_loop_default()}} is used as worker loop.
+This function takes the arguments \code{fun} and optionally \code{constants} which are passed in \code{...}.
 \subsection{Usage}{
 \if{html}{\out{<div class="r">}}\preformatted{Rush$start_workers(
   n_workers = NULL,
diff --git a/man/fun_heartbeat.Rd b/man/heartbeat.Rd
similarity index 94%
rename from man/fun_heartbeat.Rd
rename to man/heartbeat.Rd
index 6554904..098d95c 100644
--- a/man/fun_heartbeat.Rd
+++ b/man/heartbeat.Rd
@@ -1,10 +1,10 @@
 % Generated by roxygen2: do not edit by hand
 % Please edit documentation in R/heartbeat_loops.R
-\name{fun_heartbeat}
-\alias{fun_heartbeat}
+\name{heartbeat}
+\alias{heartbeat}
 \title{Heartbeat Loop}
 \usage{
-fun_heartbeat(
+heartbeat(
   network_id,
   config,
   worker_id,
diff --git a/man/worker_loop_default.Rd b/man/worker_loop_default.Rd
index fcfb3c8..4e33ce3 100644
--- a/man/worker_loop_default.Rd
+++ b/man/worker_loop_default.Rd
@@ -4,12 +4,15 @@
 \alias{worker_loop_default}
 \title{Single Task Worker Loop}
 \usage{
-worker_loop_default(fun, rush)
+worker_loop_default(fun, constants = NULL, rush)
 }
 \arguments{
 \item{fun}{(\code{function})\cr
 Function to be executed.}
 
+\item{constants}{(\code{list})\cr
+List of constants passed to \code{fun}.}
+
 \item{rush}{(\link{RushWorker})\cr
 Rush worker instance.}
 }
diff --git a/pkgdown/_pkgdown.yml b/pkgdown/_pkgdown.yml
index 923d5e2..b6118df 100644
--- a/pkgdown/_pkgdown.yml
+++ b/pkgdown/_pkgdown.yml
@@ -42,9 +42,16 @@ reference:
       - Rush
       - RushWorker
       - rsh
-  - title: Misc
+  - title: Plan
+      - rush_plan
+      - rush_available
+      - rush_config
+  - title: Worker Loop
     contents:
-      - worker_loop_default
       - start_worker
-      - fun_heartbeat
+      - worker_loop_default
+      - heartbeat
+  - title: Misc
+    contents:
+      - get_hostname
       - rush-package
diff --git a/tests/testthat/test-Rush.R b/tests/testthat/test-Rush.R
index f635e8a..491cc40 100644
--- a/tests/testthat/test-Rush.R
+++ b/tests/testthat/test-Rush.R
@@ -186,6 +186,34 @@ test_that("a remote worker is started", {
   expect_set_equal(rush$worker_info$host, "remote")
 })
 
+# start workers with script ----------------------------------------------------
+
+test_that("worker can be started with script", {
+  # skip_on_cran()
+  skip_on_ci()
+  skip_if(TRUE)
+
+  config = start_flush_redis()
+  rush = Rush$new(network_id = "test-rush", config = config)
+  fun = function(x1, x2, ...) list(y = x1 + x2)
+
+  rush$create_worker_script(fun = fun)
+})
+
+test_that("a remote worker is started", {
+  # skip_on_cran()
+
+  config = start_flush_redis()
+  fun = function(x1, x2, ...) list(y = x1 + x2)
+  rush = Rush$new(network_id = "test-rush", config = config)
+
+  withr::with_envvar(list("HOST" = "remote_host"), {
+    rush$start_workers(fun = fun, n_workers = 2, heartbeat_period = 1, heartbeat_expire = 2, await_workers = TRUE)
+  })
+
+  expect_set_equal(rush$worker_info$host, "remote")
+})
+
 # stop workers -----------------------------------------------------------------
 
 test_that("a worker is terminated", {
@@ -683,6 +711,23 @@ test_that("terminating workers on idle works", {
   expect_rush_reset(rush)
 })
 
+test_that("constants works", {
+  # skip_on_cran()
+
+  config = start_flush_redis()
+  rush = Rush$new(network_id = "test-rush", config = config)
+  fun = function(x1, x2, x3, ...) list(y = x1 + x2 + x3)
+  rush$start_workers(fun = fun, n_workers = 4, constants = list(x3 = 5), await_workers = TRUE)
+
+  xss = list(list(x1 = 1, x2 = 2))
+  keys = rush$push_tasks(xss)
+  rush$await_tasks(keys)
+
+  expect_equal(rush$fetch_finished_tasks()$y, 8)
+
+  expect_rush_reset(rush)
+})
+
 # rush network without controller ----------------------------------------------
 
 test_that("network without controller works", {
diff --git a/tests/testthat/test-rush_plan.R b/tests/testthat/test-rush_plan.R
index 77a5984..02adc3f 100644
--- a/tests/testthat/test-rush_plan.R
+++ b/tests/testthat/test-rush_plan.R
@@ -2,7 +2,6 @@ test_that("rush_plan family works", {
   skip_on_cran()
   skip_on_ci()
 
-
   expect_false(rush_available())
   config = redis_config()
   rush_plan(n_workers = 2, config)