diff --git a/README.md b/README.md
index ca27c60..d328ad9 100644
--- a/README.md
+++ b/README.md
@@ -49,10 +49,10 @@ list = Kredis.list "mylist"
 list << "hello world!"               # => RPUSH mylist "hello world!"
 [ "hello world!" ] == list.elements  # => LRANGE mylist 0, -1
 
-integer_list = Kredis.list "myintegerlist", typed: :integer
-integer_list.append([ 1, 2, 3 ])        # => RPUSH myintegerlist "1" "2" "3"
-integer_list << 4                       # => RPUSH myintegerlist "4"
-[ 1, 2, 3, 4 ] == integer_list.elements # => LRANGE myintegerlist 0 -1
+integer_list = Kredis.list "myintegerlist", typed: :integer, default: [ 1, 2, 3 ] # => EXISTS? myintegerlist, RPUSH myintegerlist "1" "2" "3"
+integer_list.append([ 4, 5, 6 ])                                                  # => RPUSH myintegerlist "4" "5" "6"
+integer_list << 7                                                                 # => RPUSH myintegerlist "7"
+[ 1, 2, 3, 4, 5, 6, 7 ] == integer_list.elements                                  # => LRANGE myintegerlist 0 -1
 
 unique_list = Kredis.unique_list "myuniquelist"
 unique_list.append(%w[ 2 3 4 ])                # => LREM myuniquelist 0, "2" + LREM myuniquelist 0, "3" + LREM myuniquelist 0, "4"  + RPUSH myuniquelist "2", "3", "4"
@@ -163,15 +163,7 @@ sleep 0.6.seconds
 false == flag.marked?           #=> EXISTS myflag
 ```
 
-And using structures on a different than the default `shared` redis instance, relying on `config/redis/secondary.yml`:
-
-```ruby
-one_string = Kredis.string "mystring"
-two_string = Kredis.string "mystring", config: :secondary
-
-one_string.value = "just on shared"
-two_string.value != one_string.value
-```
+### Models
 
 You can use all these structures in models:
 
@@ -197,6 +189,29 @@ person.morning.value = "blue"                        # => SET people:5:morning
 true == person.morning.blue?                         # => GET people:5:morning
 ```
 
+### Default values
+
+You can set a default value for all types. For example:
+
+```ruby
+list = Kredis.list "favorite_colors", default: [ "red", "green", "blue" ]
+
+# or, in a model
+class Person < ApplicationRecord
+  kredis_string :name, default: "Unknown"
+  kredis_list :favorite_colors, default: [ "red", "green", "blue" ]
+end
+```
+
+There's a performance overhead to consider though. When you first read or write an attribute in a model, Kredis will
+check if the underlying Redis key exists, while watching for concurrent changes, and if it does not,
+write the specified default value.
+
+This means that using default values in a typical Rails app additional Redis calls (WATCH, EXISTS, UNWATCH) will be
+executed for each Kredis attribute with a default value read or written during a request.
+
+### Callbacks
+
 You can also define `after_change` callbacks that trigger on mutations:
 
 ```ruby
@@ -209,6 +224,18 @@ class Person < ApplicationRecord
 end
 ```
 
+### Multiple Redis servers
+
+And using structures on a different than the default `shared` redis instance, relying on `config/redis/secondary.yml`:
+
+```ruby
+one_string = Kredis.string "mystring"
+two_string = Kredis.string "mystring", config: :secondary
+
+one_string.value = "just on shared"
+two_string.value != one_string.value
+```
+
 ## Installation
 
 1. Run `./bin/bundle add kredis`
diff --git a/lib/kredis.rb b/lib/kredis.rb
index 2505032..28f0baf 100644
--- a/lib/kredis.rb
+++ b/lib/kredis.rb
@@ -10,6 +10,7 @@
 require "kredis/log_subscriber"
 require "kredis/namespace"
 require "kredis/type_casting"
+require "kredis/default_values"
 require "kredis/types"
 require "kredis/attributes"
 
diff --git a/lib/kredis/attributes.rb b/lib/kredis/attributes.rb
index e237455..b844501 100644
--- a/lib/kredis/attributes.rb
+++ b/lib/kredis/attributes.rb
@@ -8,56 +8,56 @@ def kredis_proxy(name, key: nil, config: :shared, after_change: nil)
       kredis_connection_with __method__, name, key, config: config, after_change: after_change
     end
 
-    def kredis_string(name, key: nil, config: :shared, after_change: nil, expires_in: nil)
-      kredis_connection_with __method__, name, key, config: config, after_change: after_change, expires_in: expires_in
+    def kredis_string(name, key: nil, default: nil, config: :shared, after_change: nil, expires_in: nil)
+      kredis_connection_with __method__, name, key, default: default, config: config, after_change: after_change, expires_in: expires_in
     end
 
-    def kredis_integer(name, key: nil, config: :shared, after_change: nil, expires_in: nil)
-      kredis_connection_with __method__, name, key, config: config, after_change: after_change, expires_in: expires_in
+    def kredis_integer(name, key: nil, default: nil, config: :shared, after_change: nil, expires_in: nil)
+      kredis_connection_with __method__, name, key, default: default, config: config, after_change: after_change, expires_in: expires_in
     end
 
-    def kredis_decimal(name, key: nil, config: :shared, after_change: nil, expires_in: nil)
-      kredis_connection_with __method__, name, key, config: config, after_change: after_change, expires_in: expires_in
+    def kredis_decimal(name, key: nil, default: nil, config: :shared, after_change: nil, expires_in: nil)
+      kredis_connection_with __method__, name, key, default: default, config: config, after_change: after_change, expires_in: expires_in
     end
 
-    def kredis_datetime(name, key: nil, config: :shared, after_change: nil, expires_in: nil)
-      kredis_connection_with __method__, name, key, config: config, after_change: after_change, expires_in: expires_in
+    def kredis_datetime(name, key: nil, default: nil, config: :shared, after_change: nil, expires_in: nil)
+      kredis_connection_with __method__, name, key, default: default, config: config, after_change: after_change, expires_in: expires_in
     end
 
-    def kredis_flag(name, key: nil, config: :shared, after_change: nil, expires_in: nil)
-      kredis_connection_with __method__, name, key, config: config, after_change: after_change, expires_in: expires_in
+    def kredis_flag(name, key: nil, default: nil, config: :shared, after_change: nil, expires_in: nil)
+      kredis_connection_with __method__, name, key, default: default, config: config, after_change: after_change, expires_in: expires_in
 
       define_method("#{name}?") do
         send(name).marked?
       end
     end
 
-    def kredis_float(name, key: nil, config: :shared, after_change: nil, expires_in: nil)
-      kredis_connection_with __method__, name, key, config: config, after_change: after_change, expires_in: expires_in
+    def kredis_float(name, key: nil, default: nil, config: :shared, after_change: nil, expires_in: nil)
+      kredis_connection_with __method__, name, key, default: default, config: config, after_change: after_change, expires_in: expires_in
     end
 
     def kredis_enum(name, key: nil, values:, default:, config: :shared, after_change: nil)
       kredis_connection_with __method__, name, key, values: values, default: default, config: config, after_change: after_change
     end
 
-    def kredis_json(name, key: nil, config: :shared, after_change: nil, expires_in: nil)
-      kredis_connection_with __method__, name, key, config: config, after_change: after_change, expires_in: expires_in
+    def kredis_json(name, key: nil, default: nil, config: :shared, after_change: nil, expires_in: nil)
+      kredis_connection_with __method__, name, key, default: default, config: config, after_change: after_change, expires_in: expires_in
     end
 
-    def kredis_list(name, key: nil, typed: :string, config: :shared, after_change: nil)
-      kredis_connection_with __method__, name, key, typed: typed, config: config, after_change: after_change
+    def kredis_list(name, key: nil, default: nil, typed: :string, config: :shared, after_change: nil)
+      kredis_connection_with __method__, name, key, default: default, typed: typed, config: config, after_change: after_change
     end
 
-    def kredis_unique_list(name, limit: nil, key: nil, typed: :string, config: :shared, after_change: nil)
-      kredis_connection_with __method__, name, key, limit: limit, typed: typed, config: config, after_change: after_change
+    def kredis_unique_list(name, limit: nil, key: nil, default: nil, typed: :string, config: :shared, after_change: nil)
+      kredis_connection_with __method__, name, key, default: default, limit: limit, typed: typed, config: config, after_change: after_change
     end
 
-    def kredis_ordered_set(name, limit: nil, key: nil, typed: :string, config: :shared, after_change: nil)
-      kredis_connection_with __method__, name, key, limit: limit, typed: typed, config: config, after_change: after_change
+    def kredis_set(name, key: nil, default: nil, typed: :string, config: :shared, after_change: nil)
+      kredis_connection_with __method__, name, key, default: default, typed: typed, config: config, after_change: after_change
     end
 
-    def kredis_set(name, key: nil, typed: :string, config: :shared, after_change: nil)
-      kredis_connection_with __method__, name, key, typed: typed, config: config, after_change: after_change
+    def kredis_ordered_set(name, limit: nil, default: nil, key: nil, typed: :string, config: :shared, after_change: nil)
+      kredis_connection_with __method__, name, key, default: default, limit: limit, typed: typed, config: config, after_change: after_change
     end
 
     def kredis_slot(name, key: nil, config: :shared, after_change: nil)
@@ -68,16 +68,16 @@ def kredis_slots(name, available:, key: nil, config: :shared, after_change: nil)
       kredis_connection_with __method__, name, key, available: available, config: config, after_change: after_change
     end
 
-    def kredis_counter(name, key: nil, config: :shared, after_change: nil, expires_in: nil)
-      kredis_connection_with __method__, name, key, config: config, after_change: after_change, expires_in: expires_in
+    def kredis_counter(name, key: nil, default: nil, config: :shared, after_change: nil, expires_in: nil)
+      kredis_connection_with __method__, name, key, default: default, config: config, after_change: after_change, expires_in: expires_in
     end
 
-    def kredis_hash(name, key: nil, typed: :string, config: :shared, after_change: nil)
-      kredis_connection_with __method__, name, key, typed: typed, config: config, after_change: after_change
+    def kredis_hash(name, key: nil, default: nil, typed: :string, config: :shared, after_change: nil)
+      kredis_connection_with __method__, name, key, default: default, typed: typed, config: config, after_change: after_change
     end
 
-    def kredis_boolean(name, key: nil, config: :shared, after_change: nil, expires_in: nil)
-      kredis_connection_with __method__, name, key, config: config, after_change: after_change, expires_in: expires_in
+    def kredis_boolean(name, key: nil, default: nil, config: :shared, after_change: nil, expires_in: nil)
+      kredis_connection_with __method__, name, key, default: default, config: config, after_change: after_change, expires_in: expires_in
     end
 
     private
@@ -90,6 +90,7 @@ def kredis_connection_with(method, name, key, **options)
           if instance_variable_defined?(ivar_symbol)
             instance_variable_get(ivar_symbol)
           else
+            options[:default] = kredis_default_evaluated(options[:default]) if options[:default]
             new_type = Kredis.send(type, kredis_key_evaluated(key) || kredis_key_for_attribute(name), **options)
             instance_variable_set ivar_symbol,
               after_change ? enrich_after_change_with_record_access(new_type, after_change) : new_type
@@ -121,4 +122,12 @@ def enrich_after_change_with_record_access(type, original_after_change)
       when Symbol then Kredis::Types::CallbacksProxy.new(type, ->(_) { send(original_after_change) })
       end
     end
+
+    def kredis_default_evaluated(default)
+      case default
+      when Proc   then Proc.new { default.call(self) }
+      when Symbol then send(default)
+      else default
+      end
+    end
 end
diff --git a/lib/kredis/default_values.rb b/lib/kredis/default_values.rb
new file mode 100644
index 0000000..53352d2
--- /dev/null
+++ b/lib/kredis/default_values.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+module Kredis::DefaultValues
+  extend ActiveSupport::Concern
+
+  prepended do
+    attr_writer :default
+
+    proxying :watch, :unwatch, :exists?
+
+    def default
+      case @default
+      when Proc   then @default.call
+      when Symbol then send(@default)
+      else @default
+      end
+    end
+
+    private
+      def set_default
+        raise NotImplementedError, "Kredis type #{self.class} needs to define #set_default"
+      end
+  end
+
+  def initialize(...)
+    super
+
+    if default
+      watch do
+        set_default unless exists?
+
+        unwatch
+      end
+    end
+  end
+end
diff --git a/lib/kredis/types.rb b/lib/kredis/types.rb
index 47522c2..6ccdb2a 100644
--- a/lib/kredis/types.rb
+++ b/lib/kredis/types.rb
@@ -41,40 +41,40 @@ def json(key, default: nil, config: :shared, after_change: nil, expires_in: nil)
   end
 
 
-  def counter(key, expires_in: nil, config: :shared, after_change: nil)
-    type_from(Counter, config, key, after_change: after_change, expires_in: expires_in)
+  def counter(key, expires_in: nil, default: nil, config: :shared, after_change: nil)
+    type_from(Counter, config, key, after_change: after_change, default: default, expires_in: expires_in)
   end
 
   def cycle(key, values:, expires_in: nil, config: :shared, after_change: nil)
     type_from(Cycle, config, key, after_change: after_change, values: values, expires_in: expires_in)
   end
 
-  def flag(key, config: :shared, after_change: nil, expires_in: nil)
-    type_from(Flag, config, key, after_change: after_change, expires_in: expires_in)
+  def flag(key, default: nil, config: :shared, after_change: nil, expires_in: nil)
+    type_from(Flag, config, key, after_change: after_change, default: default, expires_in: expires_in)
   end
 
   def enum(key, values:, default:, config: :shared, after_change: nil)
     type_from(Enum, config, key, after_change: after_change, values: values, default: default)
   end
 
-  def hash(key, typed: :string, config: :shared, after_change: nil)
-    type_from(Hash, config, key, after_change: after_change, typed: typed)
+  def hash(key, typed: :string, default: nil, config: :shared, after_change: nil)
+    type_from(Hash, config, key, after_change: after_change, default: default, typed: typed)
   end
 
-  def list(key, typed: :string, config: :shared, after_change: nil)
-    type_from(List, config, key, after_change: after_change, typed: typed)
+  def list(key, default: nil, typed: :string, config: :shared, after_change: nil)
+    type_from(List, config, key, after_change: after_change, default: default, typed: typed)
   end
 
-  def unique_list(key, typed: :string, limit: nil, config: :shared, after_change: nil)
-    type_from(UniqueList, config, key, after_change: after_change, typed: typed, limit: limit)
+  def unique_list(key, default: nil, typed: :string, limit: nil, config: :shared, after_change: nil)
+    type_from(UniqueList, config, key, after_change: after_change, default: default, typed: typed, limit: limit)
   end
 
-  def set(key, typed: :string, config: :shared, after_change: nil)
-    type_from(Set, config, key, after_change: after_change, typed: typed)
+  def set(key, default: nil, typed: :string, config: :shared, after_change: nil)
+    type_from(Set, config, key, after_change: after_change, default: default, typed: typed)
   end
 
-  def ordered_set(key, typed: :string, limit: nil, config: :shared, after_change: nil)
-    type_from(OrderedSet, config, key, after_change: after_change, typed: typed, limit: limit)
+  def ordered_set(key, default: nil, typed: :string, limit: nil, config: :shared, after_change: nil)
+    type_from(OrderedSet, config, key, after_change: after_change, default: default, typed: typed, limit: limit)
   end
 
   def slot(key, config: :shared, after_change: nil)
diff --git a/lib/kredis/types/counter.rb b/lib/kredis/types/counter.rb
index daeb4a9..2b82981 100644
--- a/lib/kredis/types/counter.rb
+++ b/lib/kredis/types/counter.rb
@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 class Kredis::Types::Counter < Kredis::Types::Proxying
+  prepend Kredis::DefaultValues
+
   proxying :multi, :set, :incrby, :decrby, :get, :del, :exists?
 
   attr_accessor :expires_in
@@ -26,4 +28,9 @@ def value
   def reset
     del
   end
+
+  private
+    def set_default
+      increment by: default
+    end
 end
diff --git a/lib/kredis/types/enum.rb b/lib/kredis/types/enum.rb
index 985ba15..b5047d4 100644
--- a/lib/kredis/types/enum.rb
+++ b/lib/kredis/types/enum.rb
@@ -3,9 +3,13 @@
 require "active_support/core_ext/object/inclusion"
 
 class Kredis::Types::Enum < Kredis::Types::Proxying
-  proxying :set, :get, :del, :exists?
+  prepend Kredis::DefaultValues
 
-  attr_accessor :values, :default
+  InvalidDefault = Class.new(StandardError)
+
+  proxying :set, :get, :del, :exists?, :multi
+
+  attr_accessor :values
 
   def initialize(...)
     super
@@ -19,11 +23,14 @@ def value=(value)
   end
 
   def value
-    get || default
+    get
   end
 
   def reset
-    del
+    multi do
+      del
+      set_default
+    end
   end
 
   private
@@ -33,4 +40,12 @@ def define_predicates_for_values
         define_singleton_method("#{defined_value}!") { self.value = defined_value }
       end
     end
+
+    def set_default
+      if default.in?(values) || default.nil?
+        set default
+      else
+        raise InvalidDefault, "Default value #{default.inspect} for #{key} is not a valid option (Valid values: #{values.join(", ")})"
+      end
+    end
 end
diff --git a/lib/kredis/types/flag.rb b/lib/kredis/types/flag.rb
index b5902fd..b7c0491 100644
--- a/lib/kredis/types/flag.rb
+++ b/lib/kredis/types/flag.rb
@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 class Kredis::Types::Flag < Kredis::Types::Proxying
+  prepend Kredis::DefaultValues
+
   proxying :set, :exists?, :del
 
   attr_accessor :expires_in
@@ -16,4 +18,9 @@ def marked?
   def remove
     del
   end
+
+  private
+    def set_default
+      mark if default
+    end
 end
diff --git a/lib/kredis/types/hash.rb b/lib/kredis/types/hash.rb
index c33fb7a..5b76f47 100644
--- a/lib/kredis/types/hash.rb
+++ b/lib/kredis/types/hash.rb
@@ -3,6 +3,8 @@
 require "active_support/core_ext/hash"
 
 class Kredis::Types::Hash < Kredis::Types::Proxying
+  prepend Kredis::DefaultValues
+
   proxying :hget, :hset, :hmget, :hdel, :hgetall, :hkeys, :hvals, :del, :exists?
 
   attr_accessor :typed
@@ -44,4 +46,9 @@ def keys
   def values
     strings_to_types(hvals || [], typed)
   end
+
+  private
+    def set_default
+      update(**default)
+    end
 end
diff --git a/lib/kredis/types/list.rb b/lib/kredis/types/list.rb
index aa85150..0c1e06f 100644
--- a/lib/kredis/types/list.rb
+++ b/lib/kredis/types/list.rb
@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 class Kredis::Types::List < Kredis::Types::Proxying
+  prepend Kredis::DefaultValues
+
   proxying :lrange, :lrem, :lpush, :ltrim, :rpush, :exists?, :del
 
   attr_accessor :typed
@@ -30,4 +32,9 @@ def clear
   def last(n = nil)
     n ? lrange(-n, -1) : lrange(-1, -1).first
   end
+
+  private
+    def set_default
+      append default
+    end
 end
diff --git a/lib/kredis/types/ordered_set.rb b/lib/kredis/types/ordered_set.rb
index 05a4b3f..52a408d 100644
--- a/lib/kredis/types/ordered_set.rb
+++ b/lib/kredis/types/ordered_set.rb
@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 class Kredis::Types::OrderedSet < Kredis::Types::Proxying
+  prepend Kredis::DefaultValues
+
   proxying :multi, :zrange, :zrem, :zadd, :zremrangebyrank, :zcard, :exists?, :del
 
   attr_accessor :typed
@@ -74,4 +76,8 @@ def trim(from_beginning:)
         zremrangebyrank(0, -(limit + 1))
       end
     end
+
+    def set_default
+      append default
+    end
 end
diff --git a/lib/kredis/types/proxy.rb b/lib/kredis/types/proxy.rb
index b3a1d2a..6941115 100644
--- a/lib/kredis/types/proxy.rb
+++ b/lib/kredis/types/proxy.rb
@@ -22,6 +22,16 @@ def multi(*args, **kwargs, &block)
     end
   end
 
+  def watch(&block)
+    redis.watch(key) do
+      block.call
+    end
+  end
+
+  def unwatch
+    redis.unwatch
+  end
+
   def method_missing(method, *args, **kwargs)
     Kredis.instrument :proxy, **log_message(method, *args, **kwargs) do
       failsafe do
diff --git a/lib/kredis/types/scalar.rb b/lib/kredis/types/scalar.rb
index 28f365d..798b87c 100644
--- a/lib/kredis/types/scalar.rb
+++ b/lib/kredis/types/scalar.rb
@@ -1,9 +1,11 @@
 # frozen_string_literal: true
 
 class Kredis::Types::Scalar < Kredis::Types::Proxying
+  prepend Kredis::DefaultValues
+
   proxying :set, :get, :exists?, :del, :expire, :expireat
 
-  attr_accessor :typed, :default, :expires_in
+  attr_accessor :typed, :expires_in
 
   def value=(value)
     set type_to_string(value, typed), ex: expires_in
@@ -38,4 +40,9 @@ def expire_in(seconds)
   def expire_at(datetime)
     expireat datetime.to_i
   end
+
+  private
+    def set_default
+      self.value = default
+    end
 end
diff --git a/lib/kredis/types/set.rb b/lib/kredis/types/set.rb
index 870c52b..4a157b5 100644
--- a/lib/kredis/types/set.rb
+++ b/lib/kredis/types/set.rb
@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 class Kredis::Types::Set < Kredis::Types::Proxying
+  prepend Kredis::DefaultValues
+
   proxying :smembers, :sadd, :srem, :multi, :del, :sismember, :scard, :spop, :exists?, :srandmember
 
   attr_accessor :typed
@@ -49,4 +51,9 @@ def sample(count = nil)
       strings_to_types(srandmember(count), typed)
     end
   end
+
+  private
+    def set_default
+      add default
+    end
 end
diff --git a/test/attributes_test.rb b/test/attributes_test.rb
index fbd861b..a655abf 100644
--- a/test/attributes_test.rb
+++ b/test/attributes_test.rb
@@ -12,25 +12,38 @@ class Person
   kredis_list :names
   kredis_list :names_with_custom_key_via_lambda, key: ->(p) { "person:#{p.id}:names_customized" }
   kredis_list :names_with_custom_key_via_method, key: :generate_key
+  kredis_list :names_with_default_via_lambda, default: ->(p) { ["Random", p.name] }
   kredis_unique_list :skills, limit: 2
+  kredis_unique_list :skills_with_default_via_lambda, default: ->(p) { ["Random", "Random", p.name] }
   kredis_ordered_set :reading_list, limit: 2
   kredis_flag :special
   kredis_flag :temporary_special, expires_in: 1.second
   kredis_string :address
+  kredis_string :address_with_default_via_lambda, default: ->(p) { p.name }
   kredis_integer :age
+  kredis_integer :age_with_default_via_lambda, default: ->(p) { Date.today.year - p.birthdate.year }
   kredis_decimal :salary
+  kredis_decimal :salary_with_default_via_lambda, default: ->(p) { p.hourly_wage * 40 * 52 }
   kredis_datetime :last_seen_at
+  kredis_datetime :last_seen_at_with_default_via_lambda, default: ->(p) { p.last_login }
   kredis_float :height
+  kredis_float :height_with_default_via_lambda, default: ->(p) { JSON.parse(p.anthropometry)["height"] }
   kredis_enum :morning, values: %w[ bright blue black ], default: "bright"
+  kredis_enum :eye_color_with_default_via_lambda, values: %w[ hazel blue brown ], default: ->(p) { { ha: "hazel", bl: "blue", br: "brown" }[p.eye_color.to_sym] }
   kredis_slot :attention
   kredis_slots :meetings, available: 3
   kredis_set :vacations
+  kredis_set :vacations_with_default_via_lambda, default: ->(p) { JSON.parse(p.vacation_destinations).map { |location| location["city"] } }
   kredis_json :settings
+  kredis_json :settings_with_default_via_lambda, default: ->(p) { JSON.parse(p.anthropometry).merge(eye_color: p.eye_color) }
   kredis_counter :amount
+  kredis_counter :amount_with_default_via_lambda, default: ->(p) { Date.today.year - p.birthdate.year }
   kredis_counter :expiring_amount, expires_in: 1.second
   kredis_string :temporary_password, expires_in: 1.second
   kredis_hash :high_scores, typed: :integer
+  kredis_hash :high_scores_with_default_via_lambda, typed: :integer, default: ->(p) { { high_score: JSON.parse(p.scores).max } }
   kredis_boolean :onboarded
+  kredis_boolean :adult_with_default_via_lambda, default: ->(p) { Date.today.year - p.birthdate.year >= 18 }
 
   def self.name
     "Person"
@@ -40,6 +53,41 @@ def id
     8
   end
 
+  def name
+    "Jason"
+  end
+
+  def birthdate
+    Date.today - 25.years
+  end
+
+  def anthropometry
+    { height: 73.2, weight: 182.4 }.to_json
+  end
+
+  def eye_color
+    "ha"
+  end
+
+  def scores
+    [10, 28, 2, 7].to_json
+  end
+
+  def hourly_wage
+    15.26
+  end
+
+  def last_login
+    Time.new(2002, 10, 31, 2, 2, 2, "+02:00")
+  end
+
+  def vacation_destinations
+    [
+      { city: "Paris", region: "Île-de-France", country: "FR" },
+      { city: "Paris", region: "Texas", country: "US" }
+    ].to_json
+  end
+
   private
     def generate_key
       "some-generated-key"
@@ -86,6 +134,11 @@ class AttributesTest < ActiveSupport::TestCase
     assert_equal %w[ david kasper ], Kredis.redis.lrange("some-generated-key", 0, -1)
   end
 
+  test "list with default proc value" do
+    assert_equal %w[ Random Jason ], @person.names_with_default_via_lambda.elements
+    assert_equal %w[ Random Jason ], Kredis.redis.lrange("people:8:names_with_default_via_lambda", 0, -1)
+  end
+
   test "unique list" do
     @person.skills.prepend(%w[ trolling photography ])
     @person.skills.prepend("racing")
@@ -93,6 +146,11 @@ class AttributesTest < ActiveSupport::TestCase
     assert_equal %w[ racing photography ], @person.skills.elements
   end
 
+  test "unique list with default proc value" do
+    assert_equal %w[ Random Jason ], @person.skills_with_default_via_lambda.elements
+    assert_equal %w[ Random Jason ], Kredis.redis.lrange("people:8:skills_with_default_via_lambda", 0, -1)
+  end
+
   test "ordered set" do
     @person.reading_list.prepend(%w[ rework shapeup remote ])
     assert_equal %w[ remote shapeup ], @person.reading_list.elements
@@ -119,30 +177,57 @@ class AttributesTest < ActiveSupport::TestCase
     assert_not @person.address.assigned?
   end
 
+  test "string with default proc value" do
+    assert_equal "Jason", @person.address_with_default_via_lambda.to_s
+
+    @person.address.clear
+    assert_not @person.address.assigned?
+  end
+
   test "integer" do
     @person.age.value = 41
     assert_equal 41, @person.age.value
     assert_equal "41", @person.age.to_s
   end
 
+  test "integer with default proc value" do
+    assert_equal 25, @person.age_with_default_via_lambda.value
+    assert_equal "25", @person.age_with_default_via_lambda.to_s
+  end
+
   test "decimal" do
     @person.salary.value = 10000.07
     assert_equal 10000.07, @person.salary.value
     assert_equal "0.1000007e5", @person.salary.to_s
   end
 
+  test "decimal with default proc value" do
+    assert_equal 31_740.80.to_d, @person.salary_with_default_via_lambda.value
+    assert_equal "0.317408e5", @person.salary_with_default_via_lambda.to_s
+  end
+
   test "float" do
     @person.height.value = 1.85
     assert_equal 1.85, @person.height.value
     assert_equal "1.85", @person.height.to_s
   end
 
-  test "datetime" do
+  test "float with default proc value" do
+    assert_not_equal 73.2, Kredis.redis.get("people:8:height_with_default_via_lambda")
+    assert_equal 73.2, @person.height_with_default_via_lambda.value
+    assert_equal "73.2", @person.height_with_default_via_lambda.to_s
+  end
+
+  test "datetime with default proc value" do
     freeze_time
     @person.last_seen_at.value = Time.now
     assert_equal Time.now, @person.last_seen_at.value
   end
 
+  test "datetime" do
+    assert_equal Time.new(2002, 10, 31, 2, 2, 2, "+02:00"), @person.last_seen_at_with_default_via_lambda.value
+  end
+
   test "slot" do
     assert @person.attention.reserve
     assert_not @person.attention.available?
@@ -205,6 +290,11 @@ class AttributesTest < ActiveSupport::TestCase
     assert @person.morning.bright?
   end
 
+  test "enum with default proc value" do
+    assert @person.eye_color_with_default_via_lambda.hazel?
+  end
+
+
   test "set" do
     @person.vacations.add "paris"
     @person.vacations.add "paris"
@@ -220,11 +310,23 @@ class AttributesTest < ActiveSupport::TestCase
     assert_equal "paris", @person.vacations.take
   end
 
+  test "set with default proc value" do
+    assert_equal [ "Paris" ], @person.vacations_with_default_via_lambda.members
+    assert_equal [ "Paris" ], Kredis.redis.smembers("people:8:vacations_with_default_via_lambda")
+  end
+
   test "json" do
     @person.settings.value = { "color" => "red", "count" => 2 }
     assert_equal({ "color" => "red", "count" => 2 }, @person.settings.value)
   end
 
+  test "json with default proc value" do
+    expect = { "height" => 73.2, "weight" => 182.4, "eye_color" => "ha" }
+    assert_equal expect, @person.settings_with_default_via_lambda.value
+    assert_equal expect.to_json, Kredis.redis.get("people:8:settings_with_default_via_lambda")
+  end
+
+
   test "counter" do
     @person.amount.increment
     assert_equal 1, @person.amount.value
@@ -239,6 +341,13 @@ class AttributesTest < ActiveSupport::TestCase
     end
   end
 
+  test "counter with default proc value" do
+    @person.amount_with_default_via_lambda.increment
+    assert_equal 26, @person.amount_with_default_via_lambda.value
+    @person.amount_with_default_via_lambda.decrement
+    assert_equal 25, @person.amount_with_default_via_lambda.value
+  end
+
   test "hash" do
     @person.high_scores.update(space_invaders: 100, pong: 42)
     assert_equal({ "space_invaders" => 100, "pong" => 42 }, @person.high_scores.to_h)
@@ -246,6 +355,10 @@ class AttributesTest < ActiveSupport::TestCase
     assert_equal([ 100, 42 ], @person.high_scores.values)
   end
 
+  test "hash with default proc value" do
+    assert_equal({ "high_score" => 28 }, @person.high_scores_with_default_via_lambda.to_h)
+  end
+
   test "boolean" do
     @person.onboarded.value = true
     assert @person.onboarded.value
@@ -254,6 +367,10 @@ class AttributesTest < ActiveSupport::TestCase
     assert_not @person.onboarded.value
   end
 
+  test "boolean with default proc value" do
+    assert @person.adult_with_default_via_lambda.value
+  end
+
   test "missing id to constrain key" do
     assert_raise NotImplementedError do
       MissingIdPerson.new.anything
diff --git a/test/types/counter_test.rb b/test/types/counter_test.rb
index 4e4c607..3b6c8bc 100644
--- a/test/types/counter_test.rb
+++ b/test/types/counter_test.rb
@@ -80,4 +80,43 @@ class CounterTest < ActiveSupport::TestCase
     @counter.increment
     assert @counter.exists?
   end
+
+  test "default value" do
+    @counter = Kredis.counter "mycounter", default: 10
+    assert_equal 10, @counter.value
+  end
+
+  test "expiring counter with default" do
+    @counter = Kredis.counter "mycounter", default: ->() { 10 }, expires_in: 1.second
+
+    @counter.increment
+    assert_equal 11, @counter.value
+
+    sleep 0.5.seconds
+
+    @counter.increment
+    assert_equal 12, @counter.value
+
+    sleep 0.5.seconds
+
+    # Defaults are only set on initialization
+    assert_equal 0, @counter.value
+  end
+
+  test "default via proc" do
+    @counter = Kredis.counter "mycounter", default: ->() { 10 }
+    assert_equal 10, @counter.value
+    @counter.decrement
+    assert_equal 9, @counter.value
+  end
+
+  test "concurrent initialization with default" do
+    5.times.map do
+      Thread.new do
+        Kredis.counter("mycounter", default: 5).increment
+      end
+    end.each(&:join)
+
+    assert_equal 10, Kredis.counter("mycounter").value
+  end
 end
diff --git a/test/types/enum_test.rb b/test/types/enum_test.rb
index d433f8d..d89f882 100644
--- a/test/types/enum_test.rb
+++ b/test/types/enum_test.rb
@@ -9,6 +9,22 @@ class EnumTest < ActiveSupport::TestCase
     assert_equal "one", @enum.value
   end
 
+  test "default via proc" do
+    @enum = Kredis.enum "myenum2", values: %w[ one two three ], default: ->() { "two" }
+    assert_equal "two", @enum.value
+  end
+
+  test "default can be nil" do
+    enum = Kredis.enum "myenum3", values: [ 1, 2, 3 ], default: nil
+    assert_nil enum.value
+  end
+
+  test "default value has to be valid if not nil" do
+    assert_raises Kredis::Types::Enum::InvalidDefault do
+      Kredis.enum "myenum4", values: [ 1, 2, 3 ], default: 4
+    end
+  end
+
   test "predicates" do
     assert @enum.one?
 
@@ -39,9 +55,10 @@ class EnumTest < ActiveSupport::TestCase
   end
 
   test "exists?" do
-    assert_not @enum.exists?
+    enum = Kredis.enum "numbers", values: %w[ one two three ], default: nil
+    assert_not enum.exists?
 
-    @enum.value = "one"
-    assert @enum.exists?
+    enum.value = "one"
+    assert enum.exists?
   end
 end
diff --git a/test/types/hash_test.rb b/test/types/hash_test.rb
index ab9e5ad..67b3e1d 100644
--- a/test/types/hash_test.rb
+++ b/test/types/hash_test.rb
@@ -92,4 +92,36 @@ class HashTest < ActiveSupport::TestCase
     @hash[:key] = :value
     assert @hash.exists?
   end
+
+  test "default value" do
+    @hash = Kredis.hash "myhash", typed: :integer, default: { space_invaders: "100", pong: "42" }
+    assert_equal({ "space_invaders" => 100, "pong" => 42 }, @hash.to_h)
+    assert_equal(%w[ space_invaders pong ], @hash.keys)
+    assert_equal([100, 42], @hash.values)
+    assert_equal(100, @hash["space_invaders"])
+    assert_equal([100, 42], @hash.values_at("space_invaders", "pong"))
+  end
+
+  test "update with default" do
+    @hash = Kredis.hash "myhash", typed: :integer, default: { space_invaders: "100", pong: "42" }
+    @hash.update(ping: "54")
+    assert_equal(%w[ space_invaders pong ping ], @hash.keys)
+  end
+
+  test "[]= with default" do
+    @hash = Kredis.hash "myhash", typed: :integer, default: { space_invaders: "100", pong: "42" }
+    @hash[:ping] = "54"
+    assert_equal(%w[ space_invaders pong ping ], @hash.keys)
+  end
+
+  test "delete with default" do
+    @hash = Kredis.hash "myhash", typed: :integer, default: { space_invaders: "100", pong: "42" }
+    @hash.delete(:pong)
+    assert_equal(%w[ space_invaders ], @hash.keys)
+  end
+
+  test "default via proc" do
+    @hash = Kredis.hash "myhash", typed: :integer, default: ->() { { space_invaders: "100", pong: "42" } }
+    assert_equal({ "space_invaders" => 100, "pong" => 42 }, @hash.to_h)
+  end
 end
diff --git a/test/types/list_test.rb b/test/types/list_test.rb
index 93626ea..7507548 100644
--- a/test/types/list_test.rb
+++ b/test/types/list_test.rb
@@ -75,4 +75,60 @@ class ListTest < ActiveSupport::TestCase
     @list.ltrim(-3, -2)
     assert_equal %w[ 2 3 ], @list.elements
   end
+
+
+  test "default" do
+    @list = Kredis.list "mylist", default: %w[ 1 2 3 ]
+
+    assert_equal %w[ 1 2 3 ], @list.elements
+  end
+
+  test "default empty array" do
+    @list = Kredis.list "mylist", default: []
+
+    assert_equal [], @list.elements
+  end
+
+  test "default with nil" do
+    @list = Kredis.list "mylist", default: nil
+
+    assert_equal [], @list.elements
+  end
+
+  test "default via proc" do
+    @list = Kredis.list "mylist", default: ->() { %w[ 1 2 3 ] }
+
+    assert_equal %w[ 1 2 3 ], @list.elements
+  end
+
+  test "append with default" do
+    @list = Kredis.list "mylist", default: ->() { %w[ 1 ] }
+    @list.append(%w[ 2 3 ])
+    @list.append(4)
+    assert_equal %w[ 1 2 3 4 ], @list.elements
+  end
+
+  test "prepend with default" do
+    @list = Kredis.list "mylist", default: ->() { %w[ 1 ] }
+    @list.prepend(%w[ 2 3 ])
+    @list.prepend(4)
+    assert_equal %w[ 4 3 2 1 ], @list.elements
+  end
+
+  test "remove with default" do
+    @list = Kredis.list "mylist", default: ->() { %w[ 1 2 3 4 ] }
+    @list.remove(%w[ 1 2 ])
+    @list.remove(3)
+    assert_equal %w[ 4 ], @list.elements
+  end
+
+  test "concurrent initialization with default" do
+    5.times.map do |i|
+      Thread.new do
+        Kredis.list("mylist", default: [ 10, 20, 30 ]).append(i)
+      end
+    end.each(&:join)
+
+    assert_equal [ 0, 1, 2, 3, 4, 10, 20, 30 ], Kredis.list("mylist", typed: :integer).to_a.sort
+  end
 end
diff --git a/test/types/scalar_test.rb b/test/types/scalar_test.rb
index 5bd3bb9..41bdf60 100644
--- a/test/types/scalar_test.rb
+++ b/test/types/scalar_test.rb
@@ -116,11 +116,36 @@ class ScalarTest < ActiveSupport::TestCase
     assert_equal 8, integer.value
 
     assert_equal "8", integer.value.to_s
+    integer.clear
+
+    json = Kredis.json "myscalar", default: { one: 1, string: "hello" }
+    assert_equal({ "one" => 1, "string" => "hello" }, json.value)
+  end
+
+  test "default via proc" do
+    integer = Kredis.scalar "myscalar", typed: :integer, default: ->() { 8 }
+    assert_equal 8, integer.value
+
+    integer.value = 5
+    assert_equal 5, integer.value
+
+    integer.clear
+    assert_equal 8, integer.value
 
-    json = Kredis.json "myscalar", default: { "one" => 1, "string" => "hello" }
+    integer.clear
+
+    json = Kredis.json "myscalar", default: ->() { { one: 1, string: "hello" } }
     assert_equal({ "one" => 1, "string" => "hello" }, json.value)
   end
 
+  test "does not cache proc results after clear" do
+    hex = Kredis.scalar "myscalar", default: ->() { SecureRandom.hex }
+    original_default_value = hex.value
+    assert_equal original_default_value, hex.value
+    hex.clear
+    assert_not_equal original_default_value, hex.value
+  end
+
   test "returns default when failing open" do
     integer = Kredis.scalar "myscalar", typed: :integer, default: 8
     integer.value = 42
diff --git a/test/types/set_test.rb b/test/types/set_test.rb
index 0d0c5b4..84d2947 100644
--- a/test/types/set_test.rb
+++ b/test/types/set_test.rb
@@ -21,7 +21,7 @@ class SetTest < ActiveSupport::TestCase
 
   test "remove" do
     @set.add(%w[ 1 2 3 4 ])
-    @set.remove(%w[ 2 3 ])
+    @set.remove([%w[ 2 3 ]])
     @set.remove("1")
     assert_equal %w[ 4 ], @set.members
   end
@@ -100,4 +100,45 @@ class SetTest < ActiveSupport::TestCase
     assert @set.sample.in?([ 1.5, 2.7 ])
     assert_equal [ 1.5, 2.7 ], @set.sample(2).sort
   end
+
+
+  test "default" do
+    @set = Kredis.set "mylist", default: %w[ 1 2 3 ]
+    assert_equal %w[ 1 2 3 ], @set.members
+  end
+
+  test "default is an empty array" do
+    @set = Kredis.set "mylist", default: []
+    assert_equal [], @set.members
+  end
+
+  test "default is nil" do
+    @set = Kredis.set "mylist", default: nil
+    assert_equal [], @set.members
+  end
+
+  test "default via proc" do
+    @set = Kredis.set "mylist", default: -> () { %w[ 3 3 1 2 ] }
+    assert_equal %w[ 1 2 3 ], @set.members
+  end
+
+  test "add with default" do
+    @set = Kredis.set "mylist", typed: :integer, default: -> () { %w[ 1 2 3 ] }
+    @set.add(%w[ 5 6 7 ])
+    assert_equal [1, 2, 3, 5, 6, 7], @set.members
+  end
+
+  test "remove with default" do
+    @set = Kredis.set "mylist", default: -> () { %w[ 1 2 3 4 ] }
+    @set.remove(%w[ 2 3 ])
+    @set.remove("1")
+    assert_equal %w[ 4 ], @set.members
+  end
+
+  test "replace with default" do
+    @set = Kredis.set "mylist", typed: :integer, default: -> () { %w[ 1 2 3 ] }
+    @set.add(%w[ 5 6 7 ])
+    @set.replace(%w[ 8 9 10 ])
+    assert_equal [ 8, 9, 10 ], @set.members
+  end
 end
diff --git a/test/types/unique_list_test.rb b/test/types/unique_list_test.rb
index 83748f4..8ac91ed 100644
--- a/test/types/unique_list_test.rb
+++ b/test/types/unique_list_test.rb
@@ -75,4 +75,22 @@ class UniqueListTest < ActiveSupport::TestCase
     @list.prepend(%w[ 1 1 1 ])
     assert_equal %w[ 1 ], @list.elements
   end
+
+  test "default" do
+    @list = Kredis.unique_list "myuniquelist", default: %w[ 1 2 3 ]
+
+    assert_equal %w[ 1 2 3 ], @list.elements
+  end
+
+  test "default via proc" do
+    @list = Kredis.unique_list "myuniquelist", default: ->() { %w[ 1 2 3 3 ] }
+
+    assert_equal %w[ 1 2 3 ], @list.elements
+  end
+
+  test "prepend with default" do
+    @list = Kredis.unique_list "myuniquelist", default: %w[ 1 2 3 ]
+    @list.prepend(%w[ 6 7 8 ])
+    assert_equal %w[ 8 7 6 1 2 3 ], @list.elements
+  end
 end