diff --git a/CHANGELOG b/CHANGELOG
index d93ef0f7..53788c4e 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,5 +1,7 @@
 = master
 
+* Support :filter plugin option in error_mail and error_email for filtering parameters, environment variables, and session values (jeremyevans) (#346)
+
 * Set temporary name on Ruby 3.3 in middleware plugin for middleware class created (janko) (#344)
 
 * Add break plugin, for using break inside a routing block to return from the block and keep routing (jeremyevans)
diff --git a/lib/roda/plugins/error_email.rb b/lib/roda/plugins/error_email.rb
index bba16738..32a04d97 100644
--- a/lib/roda/plugins/error_email.rb
+++ b/lib/roda/plugins/error_email.rb
@@ -21,6 +21,9 @@ module RodaPlugins
     #
     # Options:
     #
+    # :filter :: Callable called with the key and value for each parameter, environment
+    #            variable, and session value.  If it returns true, the value of the
+    #            parameter is filtered in the email.
     # :from :: The From address to use in the email (required)
     # :headers :: A hash of additional headers to use in the email (default: empty hash)
     # :host :: The SMTP server to use to send the email (default: localhost)
@@ -38,6 +41,7 @@ module RodaPlugins
     # use an error reporting service instead of this plugin.
     module ErrorEmail
       DEFAULTS = {
+        :filter=>lambda{|k,v| false},
         :headers=>OPTS,
         :host=>'localhost',
         # :nocov:
@@ -52,7 +56,12 @@ module ErrorEmail
           {'From'=>h[:from], 'To'=>h[:to], 'Subject'=>"#{h[:prefix]}#{subject}"}
         end,
         :body=>lambda do |s, e|
-          format = lambda{|h| h.map{|k, v| "#{k.inspect} => #{v.inspect}"}.sort.join("\n")}
+          filter = s.opts[:error_email][:filter]
+          format = lambda do |h|
+            h = h.map{|k, v| "#{k.inspect} => #{filter.call(k, v) ? 'FILTERED' : v.inspect}"}
+            h.sort!
+            h.join("\n")
+          end 
 
           begin
             params = s.request.params
diff --git a/lib/roda/plugins/error_mail.rb b/lib/roda/plugins/error_mail.rb
index a532db6e..163526ef 100644
--- a/lib/roda/plugins/error_mail.rb
+++ b/lib/roda/plugins/error_mail.rb
@@ -21,6 +21,9 @@ module RodaPlugins
     #
     # Options:
     #
+    # :filter :: Callable called with the key and value for each parameter, environment
+    #            variable, and session value.  If it returns true, the value of the
+    #            parameter is filtered in the email.
     # :from :: The From address to use in the email (required)
     # :headers :: A hash of additional headers to use in the email (default: empty hash)
     # :prefix :: A prefix to use in the email's subject line (default: no prefix)
@@ -36,9 +39,12 @@ module RodaPlugins
     # for low traffic web applications.  For high traffic web applications,
     # use an error reporting service instead of this plugin.
     module ErrorMail
+      DEFAULT_FILTER = lambda{|k,v| false}
+      private_constant :DEFAULT_FILTER
+
       # Set default opts for plugin.  See ErrorEmail module RDoc for options.
       def self.configure(app, opts=OPTS)
-        app.opts[:error_mail] = email_opts = (app.opts[:error_mail] || OPTS).merge(opts).freeze
+        app.opts[:error_mail] = email_opts = (app.opts[:error_mail] || {:filter=>DEFAULT_FILTER}).merge(opts).freeze
         unless email_opts[:to] && email_opts[:from]
           raise RodaError, "must provide :to and :from options to error_mail plugin"
         end
@@ -68,8 +74,13 @@ def _error_mail(e)
             e.to_s
           end
           subject = "#{email_opts[:prefix]}#{subject}"
+          filter = email_opts[:filter]
 
-          format = lambda{|h| h.map{|k, v| "#{k.inspect} => #{v.inspect}"}.sort.join("\n")}
+          format = lambda do |h|
+            h = h.map{|k, v| "#{k.inspect} => #{filter.call(k, v) ? 'FILTERED' : v.inspect}"}
+            h.sort!
+            h.join("\n")
+          end 
 
           begin
             params = request.params
diff --git a/spec/plugin/error_email_spec.rb b/spec/plugin/error_email_spec.rb
index 9dfbd7b8..f7f28e94 100644
--- a/spec/plugin/error_email_spec.rb
+++ b/spec/plugin/error_email_spec.rb
@@ -48,6 +48,16 @@ def email
     b.must_match(/^Backtrace:$.+^ENV:$.+^"rack\.input" => .+^Params:$\s+^"b" => "c"$\s+^Session:$\s+^"d" => "e"$/m)
   end
 
+  it "supports :filter plugin option for filtering parameters, environment variables, and session values" do
+    app.route do |r|
+      raise ArgumentError, 'bad foo' rescue error_email_content($!)
+    end
+    app.plugin :error_email, :filter=>proc{|k, v| k == 'b' || k == 'd' || k == 'rack.input'}
+    b = body('rack.input'=>rack_input, 'QUERY_STRING'=>'b=c&f=g', 'rack.session'=>{'d'=>'e', 'h'=>'i'})
+    b.must_match(/^Subject: ArgumentError: bad foo/)
+    b.must_match(/^Backtrace:.+^ENV:.+^"rack\.input" => FILTERED.+^Params:\s+^"b" => FILTERED\s+"f" => "g"\s+^Session:\s+^"d" => FILTERED\s+"h" => "i"/m)
+  end
+
   it "handles invalid parameters in error_email_content" do
     app.route do |r|
       raise ArgumentError, 'bad foo' rescue error_email_content($!)
diff --git a/spec/plugin/error_mail_spec.rb b/spec/plugin/error_mail_spec.rb
index e1dd7ace..b821555a 100644
--- a/spec/plugin/error_mail_spec.rb
+++ b/spec/plugin/error_mail_spec.rb
@@ -59,6 +59,16 @@ def email
     b.must_match(/^Backtrace:.+^ENV:.+^"rack\.input" => .+^Params:\s+^"b" => "c"\s+^Session:\s+^"d" => "e"/m)
   end
 
+  it "supports :filter plugin option for filtering parameters, environment variables, and session values" do
+    app.route do |r|
+      raise ArgumentError, 'bad foo' rescue error_mail_content($!)
+    end
+    app.plugin :error_mail, :filter=>proc{|k, v| k == 'b' || k == 'd' || k == 'rack.input'}
+    b = body('rack.input'=>rack_input, 'QUERY_STRING'=>'b=c&f=g', 'rack.session'=>{'d'=>'e', 'h'=>'i'})
+    b.must_match(/^Subject: ArgumentError: bad foo/)
+    b.must_match(/^Backtrace:.+^ENV:.+^"rack\.input" => FILTERED.+^Params:\s+^"b" => FILTERED\s+"f" => "g"\s+^Session:\s+^"d" => FILTERED\s+"h" => "i"/m)
+  end
+
   it "handles invalid parameters in error_mail_content" do
     app.route do |r|
       raise ArgumentError, 'bad foo' rescue error_mail_content($!)