diff --git a/README.md b/README.md
index e07764e..290401c 100644
--- a/README.md
+++ b/README.md
@@ -18,7 +18,7 @@ within your local network. It is both easy to use, and easy to install.
 * The server is powered by [rack](https://github.com/rack/rack) and [puma](https://github.com/puma/puma):
     - Accepts GraphQL requests at `/graphql`.
     - Serves client (HTML, JS, CSS).
-    - Dependencies: ActiveRecord, SQLite3, ruby-graphql.
+    - Dependencies: Sequel, SQLite3, ruby-graphql.
 * The client is a statically compiled [nanoc](https://github.com/nanoc/nanoc) website:
     - Dependencies: webpack, typescript, react.
 * The CLI controls the web server:
diff --git a/twenty-cli/lib/twenty-cli/command/mixin/sqlite_mixin.rb b/twenty-cli/lib/twenty-cli/command/mixin/sqlite_mixin.rb
index 501f209..e9b03cc 100644
--- a/twenty-cli/lib/twenty-cli/command/mixin/sqlite_mixin.rb
+++ b/twenty-cli/lib/twenty-cli/command/mixin/sqlite_mixin.rb
@@ -4,6 +4,8 @@ module Twenty::Command::SQLiteMixin
   def run_command(options)
     path = options.database || Twenty.default_database
     Twenty.establish_connection(path:)
+    require "twenty-server/migration"
+    require "twenty-server/model"
     super(options)
   end
 end
diff --git a/twenty-server/lib/twenty-server.rb b/twenty-server/lib/twenty-server.rb
index de1fb52..03b746e 100644
--- a/twenty-server/lib/twenty-server.rb
+++ b/twenty-server/lib/twenty-server.rb
@@ -2,13 +2,8 @@
 
 module Twenty
   require "fileutils"
-  require "active_record"
+  require "sequel"
   require_relative "twenty-server/path"
-  require_relative "twenty-server/graphql"
-  require_relative "twenty-server/rack"
-  require_relative "twenty-server/migration"
-  require_relative "twenty-server/model"
-  extend FileUtils
   extend Path
 
   ##
@@ -26,24 +21,24 @@ module Twenty
   #
   # @return [void]
   def self.establish_connection(path:)
-    ActiveRecord::Base.establish_connection(
-      adapter: "sqlite3",
-      database: path,
-      pool: 16
+    @connection = Sequel.connect(
+      adapter: "sqlite",
+      database: path
     )
   end
 
-  ##
-  # Prepares the parent directory of the database.
-  # @return [void]
-  # @api private
-  def self.prepare_dir
-    mkdir_p(datadir)
-    mkdir_p(tmpdir)
-    touch(default_database)
+  def self.connection
+    establish_connection unless @connection
+    @connection
+  end
+
+  begin
+    FileUtils.mkdir_p(datadir)
+    FileUtils.mkdir_p(tmpdir)
+    FileUtils.touch(default_database)
   rescue => ex
     warn "prepare_dir error: #{ex.message} (#{ex.class})"
   end
-  private_class_method :prepare_dir
-  prepare_dir
+  require_relative "twenty-server/graphql"
+  require_relative "twenty-server/rack"
 end
diff --git a/twenty-server/lib/twenty-server/graphql/mutation/create_task.rb b/twenty-server/lib/twenty-server/graphql/mutation/create_task.rb
index cd7fdd3..d1052de 100644
--- a/twenty-server/lib/twenty-server/graphql/mutation/create_task.rb
+++ b/twenty-server/lib/twenty-server/graphql/mutation/create_task.rb
@@ -6,7 +6,7 @@ module Twenty::GraphQL::Mutation
     argument :input, Twenty::GraphQL::Input::TaskInput
 
     def resolve(input:)
-      Twenty::Task.new(input.to_h).save!
+      Twenty::Task.create(input.to_h)
       {"errors" => []}
     rescue => ex
       {"errors" => [ex.message]}
diff --git a/twenty-server/lib/twenty-server/graphql/mutation/update_task.rb b/twenty-server/lib/twenty-server/graphql/mutation/update_task.rb
index 86c15af..df1a680 100644
--- a/twenty-server/lib/twenty-server/graphql/mutation/update_task.rb
+++ b/twenty-server/lib/twenty-server/graphql/mutation/update_task.rb
@@ -7,8 +7,9 @@ module Twenty::GraphQL::Mutation
     argument :input, Twenty::GraphQL::Input::TaskInput
 
     def resolve(task_id:, input:)
-      task = Twenty::Task.find_by(id: task_id)
-      task.update!(input.to_h)
+      Twenty::Task
+        .with_pk!(task_id)
+        .update!(input.to_h)
       {"errors" => []}
     rescue => ex
       {"errors" => [ex.message]}
diff --git a/twenty-server/lib/twenty-server/graphql/type/query.rb b/twenty-server/lib/twenty-server/graphql/type/query.rb
index 45a6440..fc9c5e8 100644
--- a/twenty-server/lib/twenty-server/graphql/type/query.rb
+++ b/twenty-server/lib/twenty-server/graphql/type/query.rb
@@ -11,15 +11,16 @@ module Twenty::GraphQL::Type
     end
     field :projects, [Project], null: false
 
+
     def find_task(task_id:)
-      Twenty::Task.find_by(id: task_id)
+      Twenty::Task.with_pk!(task_id)
     end
 
     def tasks(status:, project_id: nil)
       tasks = Twenty::Task
-        .where(status:)
-        .order(updated_at: :desc)
-      project_id ? tasks.where(project_id:) : tasks
+                .by_status(status)
+                .order("updated_at DESC")
+      (project_id ? tasks.where(project_id:) : tasks).all
     end
 
     def projects
diff --git a/twenty-server/lib/twenty-server/migration.rb b/twenty-server/lib/twenty-server/migration.rb
index 9d3e587..0f2a779 100644
--- a/twenty-server/lib/twenty-server/migration.rb
+++ b/twenty-server/lib/twenty-server/migration.rb
@@ -1,34 +1,25 @@
 # frozen_string_literal: true
 
 module Twenty::Migration
+  require "sequel/extensions/migration"
   ##
   # @return [String]
   #  Returns the path to twenty's migrations.
   def self.migrations_path
-    [File.join(__dir__, "migration")]
+    File.join(__dir__, "migration")
   end
 
   ##
   # Runs migrations (if neccessary).
   # @return [void]
   def self.run!
-    context.migrate
+    Sequel::Migrator.run(Twenty.connection, migrations_path)
   end
-  ActiveRecord.timestamped_migrations = false
 
   ##
   # @return [Boolean]
   #  Returns true when there are pending migrations.
   def self.pending_migrations?
-    context.open.pending_migrations.any?
+    Sequel::Migrator.is_current?(Twenty.connection, migrations_path)
   end
-
-  ##
-  # @return [ActiveRecord::MigrationContext]
-  #  Returns an instance of
-  #  {ActiveRecord::MigrationContext ActiveRecord::MigrationContext}.
-  def self.context
-    @context ||= ActiveRecord::MigrationContext.new(migrations_path)
-  end
-  private_class_method :context
 end
diff --git a/twenty-server/lib/twenty-server/migration/1_create_projects.rb b/twenty-server/lib/twenty-server/migration/1_create_projects.rb
index cd9f571..7eb2cb7 100644
--- a/twenty-server/lib/twenty-server/migration/1_create_projects.rb
+++ b/twenty-server/lib/twenty-server/migration/1_create_projects.rb
@@ -1,16 +1,16 @@
-# frozen_string_literal: true
-
-class CreateProjects < ActiveRecord::Migration[7.1]
-  def up
-    create_table(:projects) do |t|
-      t.string :name, null: false
-      t.string :path, null: false
-      t.timestamps
+Sequel.migration do
+  up do
+    create_table(:projects) do
+      primary_key :id
+      String :name, null: false
+      String :path, null: false
+      DateTime :created_at
+      DateTime :updated_at
     end
     add_index :projects, [:name, :path], unique: true
   end
 
-  def down
+  down do
     drop_table(:projects)
   end
 end
diff --git a/twenty-server/lib/twenty-server/migration/2_create_tasks.rb b/twenty-server/lib/twenty-server/migration/2_create_tasks.rb
index 4cf2adb..9ee84c8 100644
--- a/twenty-server/lib/twenty-server/migration/2_create_tasks.rb
+++ b/twenty-server/lib/twenty-server/migration/2_create_tasks.rb
@@ -1,17 +1,19 @@
 # frozen_string_literal: true
 
-class CreateTasks < ActiveRecord::Migration[7.1]
-  def up
+Sequel.migration do
+  up do
     create_table(:tasks) do |t|
-      t.string :title, null: false
-      t.text :content, null: false
-      t.integer :status, null: false, default: 0
-      t.belongs_to :project, null: false
-      t.timestamps
+      primary_key :id
+      String :title, null: false
+      Text :content, null: false
+      Integer :status, null: false, default: 0
+      DateTime :created_at
+      DateTime :updated_at
+      foreign_key :project_id, :projects, null: false
     end
   end
 
-  def down
+  down do
     drop_table(:tasks)
   end
 end
diff --git a/twenty-server/lib/twenty-server/migration/3_add_color_to_projects.rb b/twenty-server/lib/twenty-server/migration/3_add_color_to_projects.rb
index 40af3f5..949151d 100644
--- a/twenty-server/lib/twenty-server/migration/3_add_color_to_projects.rb
+++ b/twenty-server/lib/twenty-server/migration/3_add_color_to_projects.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-class AddColorToProjects < ActiveRecord::Migration[7.1]
-  def up
+Sequel.migration do
+  up do
     default = Twenty::ColorableMixin.random_color
     add_column :projects, :color, :string, null: false, default:
   end
 
-  def down
+  down do
     drop_column :projects, :color
   end
 end
diff --git a/twenty-server/lib/twenty-server/model.rb b/twenty-server/lib/twenty-server/model.rb
index 3518861..0e593b5 100644
--- a/twenty-server/lib/twenty-server/model.rb
+++ b/twenty-server/lib/twenty-server/model.rb
@@ -1,6 +1,11 @@
 # frozen_string_literal: true
 
-class Twenty::Model < ActiveRecord::Base
+module Twenty::Model
+  def self.included(model)
+    model.plugin(:validation_class_methods)
+    model.plugin(:timestamps, update_on_create: true)
+  end
+
   require_relative "model/mixin/colorable_mixin"
   require_relative "model/project"
   require_relative "model/task"
diff --git a/twenty-server/lib/twenty-server/model/mixin/colorable_mixin.rb b/twenty-server/lib/twenty-server/model/mixin/colorable_mixin.rb
index 79f3496..0243f1f 100644
--- a/twenty-server/lib/twenty-server/model/mixin/colorable_mixin.rb
+++ b/twenty-server/lib/twenty-server/model/mixin/colorable_mixin.rb
@@ -14,8 +14,9 @@ module Twenty::ColorableMixin
     "#993366", "#2200AA", "#557788", "#998877", "#BB4400"
   ]
 
-  def self.included(klass)
-    klass.before_validation :set_random_color, on: :create
+  def before_validation
+    super if defined?(super)
+    set_random_color
   end
 
   def random_color
@@ -25,6 +26,7 @@ module Twenty::ColorableMixin
   private
 
   def set_random_color
+    return if id
     self.color = random_color
   end
 end
diff --git a/twenty-server/lib/twenty-server/model/project.rb b/twenty-server/lib/twenty-server/model/project.rb
index 2474729..055d397 100644
--- a/twenty-server/lib/twenty-server/model/project.rb
+++ b/twenty-server/lib/twenty-server/model/project.rb
@@ -1,17 +1,12 @@
 # frozen_string_literal: true
 
-class Twenty::Project < Twenty::Model
+class Twenty::Project < Sequel::Model
+  include Twenty::Model
   include Twenty::ColorableMixin
-  self.table_name = "projects"
 
-  ##
-  # Validations
-  validates :name, presence: true
-  validates :path, presence: true
-
-  ##
-  # Associations
-  has_many :tasks, class_name: "Twenty::Task"
+  validates_presence_of :name
+  validates_presence_of :path
+  one_to_many :tasks, class_name: "Twenty::Task"
 
   ##
   # @return [String]
diff --git a/twenty-server/lib/twenty-server/model/task.rb b/twenty-server/lib/twenty-server/model/task.rb
index 01d1212..f82655e 100644
--- a/twenty-server/lib/twenty-server/model/task.rb
+++ b/twenty-server/lib/twenty-server/model/task.rb
@@ -1,18 +1,32 @@
 # frozen_string_literal: true
 
-class Twenty::Task < Twenty::Model
-  self.table_name = "tasks"
+class Twenty::Task < Sequel::Model
+  include Twenty::Model
 
-  STATUS = {backlog: 0, ready: 1, in_progress: 2, complete: 3}
-  enum :status, STATUS, default: :backlog
+  plugin(:enum)
+  STATUS_MAP  = {backlog: 0, ready: 1, in_progress: 2, complete: 3}
+  STATUS_KEYS = STATUS_MAP.keys
+  enum :status, STATUS_MAP
 
-  ##
-  # Validations
-  validates :title, presence: true
-  validates :content, presence: true
-  validates :project, presence: true
+  def self.by_status(status)
+    if STATUS_KEYS.any? { _1.to_s == status.to_s }
+      public_send(status)
+    else
+      where(id: nil)
+    end
+  end
 
-  ##
-  # Associations
-  belongs_to :project, class_name: "Twenty::Project"
+  validates_presence_of :title
+  validates_presence_of :content
+  validates_presence_of :project
+  validates_inclusion_of :status, in: [STATUS_KEYS, *STATUS_KEYS.map(&:to_s)]
+  many_to_one :project, class_name: "Twenty::Project"
+
+  def status=(v)
+    super(v.to_sym)
+  end
+
+  def status
+    super.to_s
+  end
 end
diff --git a/twenty-server/twenty-server.gemspec b/twenty-server/twenty-server.gemspec
index 6a4aca0..6b09db0 100644
--- a/twenty-server/twenty-server.gemspec
+++ b/twenty-server/twenty-server.gemspec
@@ -15,7 +15,7 @@ Gem::Specification.new do |gem|
   gem.require_paths = ["lib"]
   gem.summary = "twenty: server-side component"
   gem.description = gem.summary
-  gem.add_runtime_dependency "activerecord", "~> 7.1"
+  gem.add_runtime_dependency "sequel", "~> 5.78"
   gem.add_runtime_dependency "sqlite3", "~> 1.6"
   gem.add_runtime_dependency "graphql", "~> 2.2"
   gem.add_runtime_dependency "server.rb", "~> 0.1"
diff --git a/twenty-server/twenty-server.gemspec.erb b/twenty-server/twenty-server.gemspec.erb
index 372b9cc..62a3475 100644
--- a/twenty-server/twenty-server.gemspec.erb
+++ b/twenty-server/twenty-server.gemspec.erb
@@ -15,7 +15,7 @@ Gem::Specification.new do |gem|
   gem.require_paths = ["lib"]
   gem.summary = "twenty: server-side component"
   gem.description = gem.summary
-  gem.add_runtime_dependency "activerecord", "~> 7.1"
+  gem.add_runtime_dependency "sequel", "~> 5.78"
   gem.add_runtime_dependency "sqlite3", "~> 1.6"
   gem.add_runtime_dependency "graphql", "~> 2.2"
   gem.add_runtime_dependency "server.rb", "~> 0.1"