diff --git a/src/env.jl b/src/env.jl
index 86a593c..665a2f3 100644
--- a/src/env.jl
+++ b/src/env.jl
@@ -1,20 +1,22 @@
-dash_env_key(name::String) =  "DASH_" * uppercase(name)
+const DASH_ENV_PREFIX = "DASH_"
 
-dash_env(name::String, default = nothing) = get(ENV, dash_env_key(name), default)
+dash_env_key(name::String; prefix = DASH_ENV_PREFIX) =  prefix * uppercase(name)
 
-function dash_env(t::Type{T}, name::String, default = nothing) where {T<:Number}    
-    key = dash_env_key(name)
-    !haskey(ENV, key) && return default    
+dash_env(name::String, default = nothing; prefix = DASH_ENV_PREFIX) = get(ENV, dash_env_key(name, prefix = prefix), default)
+
+function dash_env(t::Type{T}, name::String, default = nothing; prefix = DASH_ENV_PREFIX) where {T<:Number}
+    key = dash_env_key(name, prefix = prefix)
+    !haskey(ENV, key) && return default
     return parse(T, lowercase(get(ENV, key, "")))
 end
 
-dash_env(t::Type{String}, name::String, default = nothing) = dash_env(name, default)
+dash_env(t::Type{String}, name::String, default = nothing; prefix = DASH_ENV_PREFIX) = dash_env(name, default, prefix = prefix)
 
 
 macro env_default!(name, type = String, default = nothing)
     name_str = string(name)
     return esc(:(
-        $name = isnothing($name) ? 
+        $name = isnothing($name) ?
         dash_env($type, $name_str, $default)
         :
         $name
diff --git a/src/server.jl b/src/server.jl
index f207e41..485fbaa 100644
--- a/src/server.jl
+++ b/src/server.jl
@@ -1,4 +1,3 @@
-
 """
     run_server(app::DashApp, host = HTTP.Sockets.localhost, port = 8050; debug::Bool = false)
 
@@ -22,7 +21,9 @@ julia> run_server(handler,  HTTP.Sockets.localhost, 8050)
 ```
 
 """
-function run_server(app::DashApp, host = HTTP.Sockets.localhost, port = 8050;
+function run_server(app::DashApp,
+            host = dash_env("HOST", "127.0.0.1", prefix = ""),
+            port = dash_env(Int64, "PORT", 8050, prefix = "");
             debug = nothing,
             dev_tools_ui = nothing,
             dev_tools_props_check = nothing,
diff --git a/src/utils/paths.jl b/src/utils/paths.jl
index c3eb023..ca0d493 100644
--- a/src/utils/paths.jl
+++ b/src/utils/paths.jl
@@ -5,12 +5,12 @@ end
 
 function app_root_path()
     prog_path = program_path()
-    
+
     return isnothing(prog_path) ? pwd() : prog_path
 end
 
 function pathname_configs(url_base_pathname, requests_pathname_prefix, routes_pathname_prefix)
-    
+
     raise_error = (s) -> error("""
     $s This is ambiguous.
     To fix this, set `routes_pathname_prefix` instead of `url_base_pathname`.
@@ -42,8 +42,13 @@ function pathname_configs(url_base_pathname, requests_pathname_prefix, routes_pa
 
     !startswith(routes_pathname_prefix, "/") && error("routes_pathname_prefix` needs to start with `/`")
     !endswith(routes_pathname_prefix, "/") && error("routes_pathname_prefix` needs to end with `/`")
-    
-    if isnothing(requests_pathname_prefix)
+
+    app_name = dash_env("APP_NAME")
+
+
+    if isnothing(requests_pathname_prefix) && !isnothing(app_name)
+        requests_pathname_prefix = "/" * app_name * routes_pathname_prefix
+    elseif isnothing(requests_pathname_prefix)
         requests_pathname_prefix = routes_pathname_prefix
     end
 
@@ -51,6 +56,6 @@ function pathname_configs(url_base_pathname, requests_pathname_prefix, routes_pa
              error("requests_pathname_prefix` needs to start with `/`")
     !endswith(requests_pathname_prefix, routes_pathname_prefix) &&
              error("requests_pathname_prefix` needs to end with `routes_pathname_prefix`")
-    
+
     return (url_base_pathname, requests_pathname_prefix, routes_pathname_prefix)
 end
\ No newline at end of file
diff --git a/test/config_functional.jl b/test/config_functional.jl
index 094714e..8935fae 100644
--- a/test/config_functional.jl
+++ b/test/config_functional.jl
@@ -5,15 +5,15 @@ using HTTP
 
 
 
-@testset "external_stylesheets" begin    
+@testset "external_stylesheets" begin
     app = dash()
-    resources = ApplicationResources(app, main_registry()) 
+    resources = ApplicationResources(app, main_registry())
     index_page = Dash.index_page(app, resources)
-    
+
     @test isnothing(findfirst("link rel=\"stylesheet\"", index_page))
-    
+
     app = dash(external_stylesheets = ["https://test.css"])
-    resources = ApplicationResources(app, main_registry()) 
+    resources = ApplicationResources(app, main_registry())
     index_page = Dash.index_page(app, resources)
     @test !isnothing(findfirst("<link rel=\"stylesheet\" href=\"https://test.css\">", index_page))
 
@@ -22,54 +22,57 @@ using HTTP
          Dict("href" => "https://test2.css", "rel" => "stylesheet")
          ]
          )
-    resources = ApplicationResources(app, main_registry()) 
+    resources = ApplicationResources(app, main_registry())
     index_page = Dash.index_page(app, resources)
-    
+
     @test !isnothing(findfirst("<link rel=\"stylesheet\" href=\"https://test.css\">", index_page))
     @test !isnothing(findfirst("href=\"https://test2.css\"", index_page))
-    
+
 end
 
 @testset "external_scripts" begin
-    
-    
+
+
     app = dash(external_scripts = ["https://test.js"])
-    resources = ApplicationResources(app, main_registry()) 
+    resources = ApplicationResources(app, main_registry())
     index_page = Dash.index_page(app, resources)
     @test !isnothing(findfirst("""<script src="https://test.js"></script>""", index_page))
 
     app = dash(external_scripts = [
-        "https://test.js",  
+        "https://test.js",
         Dict("src" => "https://test2.js", "crossorigin" => "anonymous")
         ])
-    resources = ApplicationResources(app, main_registry()) 
+    resources = ApplicationResources(app, main_registry())
     index_page = Dash.index_page(app, resources)
 
     @test !isnothing(findfirst("""<script src="https://test.js"></script>""", index_page))
-    
+
     @test !isnothing(findfirst("""<script src="https://test2.js" crossorigin="anonymous"></script>""", index_page))
 
 end
 
 @testset "url paths" begin
-    #=app = dash(requests_pathname_prefix = "/reg/prefix/", routes_pathname_prefix = "/prefix/")
-    resources = ApplicationResources(app, main_registry()) 
-    index_page = Dash.index_page(app, resources)
-    
-    @test !isnothing(findfirst("""requests_pathname_prefix":"/reg/prefix/""", index_page))
-    handler = Dash.make_handler(app)
-    request = HTTP.Request("GET", "/prefix/")
-    response = handler(request)
-    @test response.status == 200
-
-    request = HTTP.Request("GET", "/prefix/_dash-layout")
-    response = handler(request)
-    @test response.status == 200
-
-    request = HTTP.Request("GET", "/prefix/_dash-dependencies")
-    response = handler(request)
-    @test response.status == 200=#
-        
+    app = dash(requests_pathname_prefix = "/reg/prefix/", routes_pathname_prefix = "/prefix/")
+    @test app.config.requests_pathname_prefix == "/reg/prefix/"
+    @test app.config.routes_pathname_prefix == "/prefix/"
+
+    app = dash(routes_pathname_prefix = "/prefix/")
+    @test app.config.routes_pathname_prefix == "/prefix/"
+    @test app.config.requests_pathname_prefix == "/prefix/"
+
+    app = dash()
+    @test app.config.routes_pathname_prefix == "/"
+    @test app.config.requests_pathname_prefix == "/"
+
+    ENV["DASH_APP_NAME"] = "test-app"
+    app = dash(routes_pathname_prefix = "/prefix/")
+    @test app.config.routes_pathname_prefix == "/prefix/"
+    @test app.config.requests_pathname_prefix == "/test-app/prefix/"
+
+    app = dash()
+    @test app.config.routes_pathname_prefix == "/"
+    @test app.config.requests_pathname_prefix == "/test-app/"
+
 end
 
 @testset "assets paths" begin
@@ -131,13 +134,13 @@ end
 
 @testset "suppress_callback_exceptions" begin
     app = dash()
-    resources = ApplicationResources(app, main_registry()) 
+    resources = ApplicationResources(app, main_registry())
     index_page = Dash.index_page(app, resources)
     @test !isnothing(findfirst("\"suppress_callback_exceptions\":false", index_page))
     @test isnothing(findfirst("\"suppress_callback_exceptions\":true", index_page))
 
     app = dash(suppress_callback_exceptions = true)
-    resources = ApplicationResources(app, main_registry()) 
+    resources = ApplicationResources(app, main_registry())
     index_page = Dash.index_page(app, resources)
     @test isnothing(findfirst("\"suppress_callback_exceptions\":false", index_page))
     @test !isnothing(findfirst("\"suppress_callback_exceptions\":true", index_page))
@@ -145,9 +148,9 @@ end
 
 @testset "meta_tags" begin
     app = dash()
-    resources = ApplicationResources(app, main_registry()) 
+    resources = ApplicationResources(app, main_registry())
     index_page = Dash.index_page(app, resources)
-    
+
     @test !isnothing(
         findfirst(
             "<meta http-equiv=\"X-UA-Compatible\" content=\"IE=edge\">",
@@ -161,7 +164,7 @@ end
         )
 
     app = dash(meta_tags = [Dict("type" => "tst", "rel" => "r")])
-    resources = ApplicationResources(app, main_registry()) 
+    resources = ApplicationResources(app, main_registry())
     index_page = Dash.index_page(app, resources)
 
     @test !isnothing(
@@ -169,13 +172,13 @@ end
                 "<meta http-equiv=\"X-UA-Compatible\" content=\"IE=edge\">",
                 index_page)
             )
-    
+
     @test !isnothing(
             findfirst(
                 "<meta charset=\"UTF-8\">",
                 index_page)
             )
-    
+
     @test !isnothing(
         findfirst(
             Dash.format_tag("meta", Dict("type" => "tst", "rel" => "r"), opened = true),
@@ -183,7 +186,7 @@ end
         )
 
  app = dash(meta_tags = [Dict("charset" => "Win1251"), Dict("type" => "tst", "rel" => "r")])
-    resources = ApplicationResources(app, main_registry()) 
+    resources = ApplicationResources(app, main_registry())
     index_page = Dash.index_page(app, resources)
 
     @test isnothing(
@@ -204,7 +207,7 @@ end
         )
 
     app = dash(meta_tags = [Dict("http-equiv" => "X-UA-Compatible", "content" => "IE"), Dict("type" => "tst", "rel" => "r")])
-    resources = ApplicationResources(app, main_registry()) 
+    resources = ApplicationResources(app, main_registry())
     index_page = Dash.index_page(app, resources)
     @test isnothing(
         findfirst(
@@ -222,23 +225,23 @@ end
 @testset "index_string" begin
     index_string = "test test test, {%metas%},{%title%},{%favicon%},{%css%},{%app_entry%},{%config%},{%scripts%},{%renderer%}"
     app = dash(index_string = index_string)
-    resources = ApplicationResources(app, main_registry()) 
+    resources = ApplicationResources(app, main_registry())
     index_page = Dash.index_page(app, resources)
-    @test startswith(index_page, "test test test,")  
-    
+    @test startswith(index_page, "test test test,")
+
 end
 
 @testset "show_undo_redo" begin
-    
+
     app = dash()
-    
-    resources = ApplicationResources(app, main_registry()) 
+
+    resources = ApplicationResources(app, main_registry())
     index_page = Dash.index_page(app, resources)
     @test !isnothing(findfirst("\"show_undo_redo\":false", index_page))
 
     app = dash(show_undo_redo = true)
-    
-    resources = ApplicationResources(app, main_registry()) 
+
+    resources = ApplicationResources(app, main_registry())
     index_page = Dash.index_page(app, resources)
     @test !isnothing(findfirst("\"show_undo_redo\":true", index_page))
 end
diff --git a/test/env.jl b/test/env.jl
index b88f9fa..ddf26f7 100644
--- a/test/env.jl
+++ b/test/env.jl
@@ -10,7 +10,7 @@ using Dash:dash_env, @env_default!
     ENV["DASH_STRING_TEST"] = "test_path"
     @test dash_env("string_test", "aaaa") == "test_path"
     @test_throws ArgumentError dash_env(Int, "string_test", "aaaa") == "test_path"
-    
+
     string_test = nothing
     @env_default! string_test
     @test string_test == "test_path"
@@ -18,12 +18,12 @@ using Dash:dash_env, @env_default!
     @env_default! string_test
     @test string_test == "aaaa"
 
-    
+
 
     ENV["DASH_INT_TEST"] = "100"
     @test dash_env("int_test", "aaaa") == "100"
     @test dash_env(Int, "int_test", 50) == 100
-    
+
     int_test = nothing
     @env_default! int_test Int
     @test int_test == 100
@@ -34,15 +34,26 @@ using Dash:dash_env, @env_default!
     @env_default! int_test2 Int 40
     @test int_test2 == 40
 
-    ENV["DASH_BOOL_TEST"] = "1"    
-    @test dash_env(Bool, "bool_test", 50) == true    
+    ENV["DASH_BOOL_TEST"] = "1"
+    @test dash_env(Bool, "bool_test", 50) == true
 
-    ENV["DASH_BOOL_TEST"] = "0"    
+    ENV["DASH_BOOL_TEST"] = "0"
     @test dash_env(Bool, "bool_test", 50) == false
 
-    ENV["DASH_BOOL_TEST"] = "TRUE"    
+    ENV["DASH_BOOL_TEST"] = "TRUE"
     @test dash_env(Bool, "bool_test", 50) == true
 
-    ENV["DASH_BOOL_TEST"] = "FALSE"    
+    ENV["DASH_BOOL_TEST"] = "FALSE"
     @test dash_env(Bool, "bool_test", 50) == false
 end
+
+@testset "prefixes" begin
+    ENV["DASH_HOST"] = "localhost"
+    @test dash_env("host") == "localhost"
+    @test isnothing(dash_env("host", prefix = ""))
+
+    @test dash_env(Int64, "port", 8050, prefix = "") == 8050
+    ENV["PORT"] = "2001"
+    @test isnothing(dash_env(Int64, "port"))
+    @test dash_env(Int64, "port", prefix = "") == 2001
+end
\ No newline at end of file