diff --git a/src/kemal/base_log_handler.cr b/src/kemal/base_log_handler.cr
index 2b1b992..37ee980 100644
--- a/src/kemal/base_log_handler.cr
+++ b/src/kemal/base_log_handler.cr
@@ -3,7 +3,7 @@ module Kemal
   abstract class BaseLogHandler
     include HTTP::Handler
 
-    abstract def call(context)
+    abstract def call(context : HTTP::Server::Context)
     abstract def write(message : String)
   end
 end
diff --git a/src/kemal/common_exception_handler.cr b/src/kemal/common_exception_handler.cr
index 156e27d..24eccfe 100644
--- a/src/kemal/common_exception_handler.cr
+++ b/src/kemal/common_exception_handler.cr
@@ -4,7 +4,7 @@ module Kemal
     include HTTP::Handler
     INSTANCE = new
 
-    def call(context)
+    def call(context : HTTP::Server::Context)
       begin
         call_next(context)
       rescue ex : Kemal::Exceptions::RouteNotFound
diff --git a/src/kemal/common_log_handler.cr b/src/kemal/common_log_handler.cr
index 44eb30f..37a1ea2 100644
--- a/src/kemal/common_log_handler.cr
+++ b/src/kemal/common_log_handler.cr
@@ -7,7 +7,7 @@ module Kemal
       @handler = io
     end
 
-    def call(context)
+    def call(context : HTTP::Server::Context)
       time = Time.now
       call_next(context)
       elapsed_text = elapsed_text(Time.now - time)
diff --git a/src/kemal/exceptions.cr b/src/kemal/exceptions.cr
index 03afa25..95bca29 100644
--- a/src/kemal/exceptions.cr
+++ b/src/kemal/exceptions.cr
@@ -1,19 +1,19 @@
 # Exceptions for 404 and custom errors are defined here.
 module Kemal::Exceptions
   class InvalidPathStartException < Exception
-    def initialize(method, path)
+    def initialize(method : String, path : String)
       super "Route declaration #{method} \"#{path}\" needs to start with '/', should be #{method} \"/#{path}\""
     end
   end
 
   class RouteNotFound < Exception
-    def initialize(context)
+    def initialize(context : HTTP::Server::Context)
       super "Requested path: '#{context.request.override_method.as(String)}:#{context.request.path}' was not found."
     end
   end
 
   class CustomException < Exception
-    def initialize(context)
+    def initialize(context : HTTP::Server::Context)
       super "Rendered error with #{context.response.status_code}"
     end
   end
diff --git a/src/kemal/filter_handler.cr b/src/kemal/filter_handler.cr
index 26357eb..9cc7409 100644
--- a/src/kemal/filter_handler.cr
+++ b/src/kemal/filter_handler.cr
@@ -11,7 +11,7 @@ module Kemal
     end
 
     # The call order of the filters is before_all -> before_x -> X -> after_x -> after_all
-    def call(context)
+    def call(context : HTTP::Server::Context)
       return call_next(context) unless context.route_defined?
       call_block_for_path_type("ALL", context.request.path, :before, context)
       call_block_for_path_type(context.request.override_method, context.request.path, :before, context)
@@ -26,7 +26,7 @@ module Kemal
 
     # :nodoc: This shouldn't be called directly, it's not private because I need to call it for testing purpose since I can't call the macros in the spec.
     # It adds the block for the corresponding verb/path/type combination to the tree.
-    def _add_route_filter(verb, path, type, &block : HTTP::Server::Context -> _)
+    def _add_route_filter(verb : String, path, type, &block : HTTP::Server::Context -> _)
       lookup = lookup_filters_for_path_type(verb, path, type)
       if lookup.found? && lookup.payload.is_a?(Array(FilterBlock))
         (lookup.payload.as(Array(FilterBlock))) << FilterBlock.new(&block)
@@ -36,17 +36,17 @@ module Kemal
     end
 
     # This can be called directly but it's simpler to just use the macros, it will check if another filter is not already defined for this verb/path/type and proceed to call `add_route_filter`
-    def before(verb, path = "*", &block : HTTP::Server::Context -> _)
+    def before(verb : String, path : String = "*", &block : HTTP::Server::Context -> _)
       _add_route_filter verb, path, :before, &block
     end
 
     # This can be called directly but it's simpler to just use the macros, it will check if another filter is not already defined for this verb/path/type and proceed to call `add_route_filter`
-    def after(verb, path = "*", &block : HTTP::Server::Context -> _)
+    def after(verb : String, path : String = "*", &block : HTTP::Server::Context -> _)
       _add_route_filter verb, path, :after, &block
     end
 
     # This will fetch the block for the verb/path/type from the tree and call it.
-    private def call_block_for_path_type(verb, path, type, context)
+    private def call_block_for_path_type(verb : String?, path : String, type, context : HTTP::Server::Context)
       lookup = lookup_filters_for_path_type(verb, path, type)
       if lookup.found? && lookup.payload.is_a? Array(FilterBlock)
         blocks = lookup.payload.as(Array(FilterBlock))
@@ -55,17 +55,17 @@ module Kemal
     end
 
     # This checks is filter is already defined for the verb/path/type combination
-    private def filter_for_path_type_defined?(verb, path, type)
+    private def filter_for_path_type_defined?(verb : String, path : String, type)
       lookup = @tree.find radix_path(verb, path, type)
       lookup.found? && lookup.payload.is_a? FilterBlock
     end
 
     # This returns a lookup for verb/path/type
-    private def lookup_filters_for_path_type(verb, path, type)
+    private def lookup_filters_for_path_type(verb : String?, path : String, type)
       @tree.find radix_path(verb, path, type)
     end
 
-    private def radix_path(verb, path, type : Symbol)
+    private def radix_path(verb : String?, path : String, type : Symbol)
       "#{type}/#{verb}/#{path}"
     end
 
@@ -77,7 +77,7 @@ module Kemal
         @block = ->(context : HTTP::Server::Context) { block.call(context).to_s }
       end
 
-      def call(context)
+      def call(context : HTTP::Server::Context)
         @block.call(context)
       end
     end
diff --git a/src/kemal/handler.cr b/src/kemal/handler.cr
index b9f8637..9fdbbb0 100644
--- a/src/kemal/handler.cr
+++ b/src/kemal/handler.cr
@@ -21,7 +21,7 @@ module Kemal
     end
   end
 
-    def call(env)
+    def call(env : HTTP::Server::Context)
       call_next(env)
     end
 
@@ -40,7 +40,7 @@ module Kemal
     #         puts "If the path is / i will be doing some processing here."
     #       end
     #     end
-    def only_match?(env)
+    def only_match?(env : HTTP::Server::Context)
       @@only_routes_tree.find(radix_path(env.request.method, env.request.path)).found?
     end
 
@@ -59,7 +59,7 @@ module Kemal
     #         puts "If the path is not / i will be doing some processing here."
     #       end
     #     end
-    def exclude_match?(env)
+    def exclude_match?(env : HTTP::Server::Context)
       @@exclude_routes_tree.find(radix_path(env.request.method, env.request.path)).found?
     end
 
diff --git a/src/kemal/helpers/helpers.cr b/src/kemal/helpers/helpers.cr
index 63da82a..7e55681 100644
--- a/src/kemal/helpers/helpers.cr
+++ b/src/kemal/helpers/helpers.cr
@@ -93,7 +93,7 @@ end
 # Optionally you can override the mime_type
 #
 #   send_file env, "./path/to/file", "image/jpeg"
-def send_file(env, path : String, mime_type : String? = nil)
+def send_file(env : HTTP::Server::Context, path : String, mime_type : String? = nil)
   config = Kemal.config.serve_static
   file_path = File.expand_path(path, Dir.current)
   mime_type ||= Kemal::Utils.mime_type(file_path)
@@ -128,7 +128,7 @@ def send_file(env, path : String, mime_type : String? = nil)
   return
 end
 
-private def multipart(file, env)
+private def multipart(file, env : HTTP::Server::Context)
   # See http://httpwg.org/specs/rfc7233.html
   fileb = file.size
 
@@ -187,7 +187,7 @@ end
 # Optionally you can override the mime_type
 #
 #   send_file env, data_slice, "image/jpeg"
-def send_file(env, data : Slice(UInt8), mime_type : String? = nil)
+def send_file(env : HTTP::Server::Context, data : Slice(UInt8), mime_type : String? = nil)
   mime_type ||= "application/octet-stream"
   env.response.content_type = mime_type
   env.response.content_length = data.bytesize
diff --git a/src/kemal/init_handler.cr b/src/kemal/init_handler.cr
index ce39b0a..3c61f33 100644
--- a/src/kemal/init_handler.cr
+++ b/src/kemal/init_handler.cr
@@ -5,7 +5,7 @@ module Kemal
     include HTTP::Handler
     INSTANCE = new
 
-    def call(context)
+    def call(context : HTTP::Server::Context)
       context.response.headers.add "X-Powered-By", "Kemal"
       context.response.content_type = "text/html" unless context.response.headers.has_key?("Content-Type")
       call_next context
diff --git a/src/kemal/route_handler.cr b/src/kemal/route_handler.cr
index eba1142..94066df 100644
--- a/src/kemal/route_handler.cr
+++ b/src/kemal/route_handler.cr
@@ -15,27 +15,27 @@ module Kemal
       @ws_routes = Radix::Tree(String).new
     end
 
-    def call(context)
+    def call(context : HTTP::Server::Context)
       process_request(context)
     end
 
     # Adds a given route to routing tree. As an exception each `GET` route additionaly defines
     # a corresponding `HEAD` route.
-    def add_http_route(method, path, &handler : HTTP::Server::Context -> _)
+    def add_http_route(method : String, path : String, &handler : HTTP::Server::Context -> _)
       add_to_http_radix_tree method, path, Route.new(method, path, &handler)
       add_to_http_radix_tree("HEAD", path, Route.new("HEAD", path) { |ctx| "" }) if method == "GET"
     end
 
-    def add_ws_route(path)
+    def add_ws_route(path : String)
       add_to_ws_radix_tree path
     end
 
     # Check if a route is defined and returns the lookup
-    def lookup_route(verb, path)
+    def lookup_route(verb : String, path : String)
       @http_routes.find radix_path(verb, path)
     end
 
-    def lookup_ws_route(path)
+    def lookup_ws_route(path : String)
       @ws_routes.find "/ws#{path}"
     end
 
diff --git a/src/kemal/static_file_handler.cr b/src/kemal/static_file_handler.cr
index edfdb7a..5cffa60 100644
--- a/src/kemal/static_file_handler.cr
+++ b/src/kemal/static_file_handler.cr
@@ -4,7 +4,7 @@
 
 module Kemal
   class StaticFileHandler < HTTP::StaticFileHandler
-    def call(context)
+    def call(context : HTTP::Server::Context)
       return call_next(context) if context.request.path.not_nil! == "/"
 
       unless context.request.method == "GET" || context.request.method == "HEAD"
@@ -57,7 +57,7 @@ module Kemal
       end
     end
 
-    private def etag(context, file_path)
+    private def etag(context : HTTP::Server::Context, file_path : String)
       etag = %{W/"#{File.lstat(file_path).mtime.epoch.to_s}"}
       context.response.headers["ETag"] = etag
       return false if !context.request.headers["If-None-Match"]? || context.request.headers["If-None-Match"] != etag
diff --git a/src/kemal/websocket_handler.cr b/src/kemal/websocket_handler.cr
index 2d9b396..5199839 100644
--- a/src/kemal/websocket_handler.cr
+++ b/src/kemal/websocket_handler.cr
@@ -7,7 +7,7 @@ module Kemal
       Kemal::RouteHandler::INSTANCE.add_ws_route @path
     end
 
-    def call(context)
+    def call(context : HTTP::Server::Context)
       return call_next(context) unless context.ws_route_defined?
       super
     end