diff --git a/CHANGELOG.md b/CHANGELOG.md
index 315f5e0..8a649fe 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,13 @@ Please mark backwards incompatible changes with an exclamation mark at the start
 
 ## [Unreleased]
 
+### Added
+- The `#update` method to `JayAPI::Elasticsearch::Client`.
+
+### Deprecated
+- The `Elasticsearch::QueryBuilder::Script` class is now deprecated, please
+  use `Elasticsearch::Script` instead.
+
 ## [29.7.0] - 2026-04-28
 
 ### Added
diff --git a/documentation/source/user_guidelines/elasticsearch/aggregations.rst b/documentation/source/user_guidelines/elasticsearch/aggregations.rst
index e0f0d61..9865444 100644
--- a/documentation/source/user_guidelines/elasticsearch/aggregations.rst
+++ b/documentation/source/user_guidelines/elasticsearch/aggregations.rst
@@ -326,7 +326,7 @@ The code above would produce the following query:
 
    These scripts **must** be simple strings, they do not follow the pattern of
    other scripted elements in Elasticsearch's DSL. Do not use
-   ``QueryBuilder::Script`` objects here. Their use will produce unintended
+   ``Elasticsearch::Script`` objects here. Their use will produce unintended
    results.
 
 composite
@@ -396,7 +396,7 @@ Code example:
      aggs.sum('total_sales', field: 'price')
      aggs.bucket_selector(
        'sales_bucket_filter', buckets_path: { totalSales: 'total_sales' },
-                              script: JayAPI::Elasticsearch::QueryBuilder::Script.new(source: 'params.totalSales > 200')
+                              script: JayAPI::Elasticsearch::Script.new(source: 'params.totalSales > 200')
      )
    end
 
diff --git a/lib/jay_api/elasticsearch.rb b/lib/jay_api/elasticsearch.rb
index f00a274..b8cac55 100644
--- a/lib/jay_api/elasticsearch.rb
+++ b/lib/jay_api/elasticsearch.rb
@@ -13,6 +13,7 @@
 require_relative 'elasticsearch/query_builder'
 require_relative 'elasticsearch/query_results'
 require_relative 'elasticsearch/response'
+require_relative 'elasticsearch/script'
 require_relative 'elasticsearch/search_after_results'
 require_relative 'elasticsearch/stats'
 require_relative 'elasticsearch/tasks'
diff --git a/lib/jay_api/elasticsearch/client.rb b/lib/jay_api/elasticsearch/client.rb
index 0e1ce9f..dc9dccb 100644
--- a/lib/jay_api/elasticsearch/client.rb
+++ b/lib/jay_api/elasticsearch/client.rb
@@ -96,6 +96,14 @@ def tasks
       def cluster
         @cluster ||= ::JayAPI::Elasticsearch::Cluster.new(transport_client)
       end
+
+      # Calls the +Elasticsearch::Client+'s #update method forwarding the given
+      # parameters. If the request fails, additional retries will be performed.
+      # @see Elasticsearch::API::Actions#update for more info about the
+      #   arguments and the return value.
+      def update(**args)
+        retry_request { transport_client.update(**args) }
+      end
     end
   end
 end
diff --git a/lib/jay_api/elasticsearch/index.rb b/lib/jay_api/elasticsearch/index.rb
index df15a97..a96dd5f 100644
--- a/lib/jay_api/elasticsearch/index.rb
+++ b/lib/jay_api/elasticsearch/index.rb
@@ -1,5 +1,8 @@
 # frozen_string_literal: true
 
+require 'active_support'
+require 'active_support/core_ext/object/blank'
+
 require_relative 'indexable'
 require_relative 'indices/settings'
 require_relative 'errors/writable_index_error'
@@ -52,6 +55,46 @@ def index(data, type: DEFAULT_DOC_TYPE)
         super.first
       end
 
+      # Updates a document by ID.
+      # @param [String] id The ID of the document to update.
+      # @param [Hash, nil] doc The partial document to update the existing
+      #   document with. If +nil+ is given, the +script+ parameter must be
+      #   provided. If both +doc+ and +script+ are given, the +doc+ parameter
+      #   will be ignored by Elasticsearch.
+      # @param [JayAPI::Elasticsearch::Script, Hash, nil] script The script to
+      #   update the existing document with. If +nil+ is given, the +doc+
+      #   parameter must be provided. It's recommended to use a
+      #   +JayAPI::Elasticsearch::Script+ object, but a Hash can also be used.
+      # @return [Hash] A Hash containing information about the updated document.
+      #   An example of such Hash is:
+      #
+      #  {
+      #     "_index" : "xyz01_build_properties",
+      #     "_type" : "_doc",
+      #     "_id" : "ns4AAZ8BXEjZhYMmw-8y",
+      #     "_version" : 7,
+      #     "result" : "updated",
+      #     "_shards" : {
+      #       "total" : 2,
+      #       "successful" : 2,
+      #       "failed" : 0
+      #     },
+      #     "_seq_no" : 11,
+      #     "_primary_term" : 1
+      #   }
+      #
+      # For information on how to use the script and about the contents of the
+      # returned Hash please see:
+      # https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-update
+      # @raise [ArgumentError] If both +doc+ and +script+ are +nil+.
+      # @raise [Elasticsearch::Transport::Transport::ServerError] If the
+      #   update fails.
+      def update(id:, doc: nil, script: nil)
+        raise ArgumentError, "Either 'doc' or 'script' must be provided" if doc.blank? && script.blank?
+
+        client.update(index: index_name, id:, body: { doc: doc, script: script&.to_h }.compact)
+      end
+
       # @return [JayAPI::Elasticsearch::Indices::Settings] The settings for the
       #   index.
       def settings
diff --git a/lib/jay_api/elasticsearch/query_builder/aggregations/bucket_selector.rb b/lib/jay_api/elasticsearch/query_builder/aggregations/bucket_selector.rb
index 079305f..6292905 100644
--- a/lib/jay_api/elasticsearch/query_builder/aggregations/bucket_selector.rb
+++ b/lib/jay_api/elasticsearch/query_builder/aggregations/bucket_selector.rb
@@ -19,8 +19,8 @@ class BucketSelector < ::JayAPI::Elasticsearch::QueryBuilder::Aggregations::Aggr
           #   The keys are the names of the script variables, the values the
           #   paths to the metrics (relative to the parent aggregation).
           #   The script will receive these variables in its +params+.
-          # @param [JayAPI::Elasticsearch::QueryBuilder::Script] script
-          #   Script used to decide whether to keep each bucket.
+          # @param [JayAPI::Elasticsearch::Script] script Script used to decide
+          #   whether to keep each bucket.
           # @param [String, nil] gap_policy Optional gap policy (e.g. "skip",
           #   "insert_zeros").
           def initialize(name, buckets_path:, script:, gap_policy: nil)
diff --git a/lib/jay_api/elasticsearch/query_builder/aggregations/terms.rb b/lib/jay_api/elasticsearch/query_builder/aggregations/terms.rb
index 290a1d4..18aab7f 100644
--- a/lib/jay_api/elasticsearch/query_builder/aggregations/terms.rb
+++ b/lib/jay_api/elasticsearch/query_builder/aggregations/terms.rb
@@ -19,10 +19,9 @@ class Terms < ::JayAPI::Elasticsearch::QueryBuilder::Aggregations::Aggregation
           # @param [String] name The name used by Elasticsearch to identify each
           #   of the aggregations.
           # @param [String] field The field whose unique values should be counted.
-          # @param [JayAPI::Elasticsearch::QueryBuilder::Script] script If a
-          #   script is given the aggregation will count the unique values
-          #   returned by the script instead of the unique values in a specific
-          #   field.
+          # @param [JayAPI::Elasticsearch::Script] script If a script is given
+          #   the aggregation will count the unique values returned by the
+          #   script instead of the unique values in a specific field.
           # @param [Integer] size By default the aggregation returns the top 10
           #   unique values (the ones with the higher frequency). By specifying
           #   a size this can be changed.
diff --git a/lib/jay_api/elasticsearch/query_builder/script.rb b/lib/jay_api/elasticsearch/query_builder/script.rb
index aed13db..b5d2540 100644
--- a/lib/jay_api/elasticsearch/query_builder/script.rb
+++ b/lib/jay_api/elasticsearch/query_builder/script.rb
@@ -1,36 +1,15 @@
 # frozen_string_literal: true
 
+require_relative '../script'
+
 module JayAPI
   module Elasticsearch
     class QueryBuilder
       # Represents a scripted element in a query. This scripted element can be
       # used in different places. It can be used in a query clause, but can
       # also be used to create custom aggregations.
-      class Script
-        attr_reader :source, :lang, :params
-
-        # @param [String] source The source for the script element.
-        # @param [String] lang The language the script is written in.
-        # @param [Hash] params A +Hash+ with key-value pairs for the script's
-        #   parameters.
-        def initialize(source:, lang: 'painless', params: nil)
-          @source = source
-          @lang = lang
-
-          # Keeps the parameters from being modified from the outside after the
-          # class has been initialized.
-          @params = params.dup.freeze
-        end
-
-        # @return [Hash] The hash representation of the scripted element.
-        def to_h
-          {
-            source: source,
-            lang: lang,
-            params: params
-          }.compact
-        end
-      end
+      # @deprecated Use +JayAPI::Elasticsearch::Script+ instead.
+      Script = JayAPI::Elasticsearch::Script
     end
   end
 end
diff --git a/lib/jay_api/elasticsearch/script.rb b/lib/jay_api/elasticsearch/script.rb
new file mode 100644
index 0000000..0c8ff9a
--- /dev/null
+++ b/lib/jay_api/elasticsearch/script.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+module JayAPI
+  module Elasticsearch
+    # Represents a scripted element in Elasticsearch. This scripted element
+    # can be used in different places. It can be used in a query clause, but can
+    # also be used to create custom aggregations or when updating documents.
+    class Script
+      attr_reader :source, :lang, :params
+
+      # @param [String] source The source for the script element.
+      # @param [String] lang The language the script is written in.
+      # @param [Hash] params A +Hash+ with key-value pairs for the script's
+      #   parameters.
+      def initialize(source:, lang: 'painless', params: nil)
+        @source = source
+        @lang = lang
+
+        # Keeps the parameters from being modified from the outside after the
+        # class has been initialized.
+        @params = params.dup.freeze
+      end
+
+      # @return [Hash] The hash representation of the scripted element.
+      def to_h
+        {
+          source: source,
+          lang: lang,
+          params: params
+        }.compact
+      end
+    end
+  end
+end
diff --git a/spec/integration/jay_api/elasticsearch/client_spec.rb b/spec/integration/jay_api/elasticsearch/client_spec.rb
index 37c0a3b..2dd0cfe 100644
--- a/spec/integration/jay_api/elasticsearch/client_spec.rb
+++ b/spec/integration/jay_api/elasticsearch/client_spec.rb
@@ -364,4 +364,21 @@
       expect(method_call).to be(cluster)
     end
   end
+
+  describe '#update' do
+    let(:method_name) { :update }
+
+    let(:client_method_arguments) do
+      {
+        index: 'xyz01_integration_test',
+        id: 'ns4AAZ8BXEjZhYMmw-8y',
+        body: { doc: { test_case: { owner: 'alice.wolf' } } }
+      }
+    end
+
+    let(:used_client) { transport_client }
+    let(:client_method_name) { :update }
+
+    it_behaves_like 'JayAPI::Elasticsearch::Client#<any_method>'
+  end
 end
diff --git a/spec/jay_api/elasticsearch/index_spec.rb b/spec/jay_api/elasticsearch/index_spec.rb
index c3ba7f7..25c6d83 100644
--- a/spec/jay_api/elasticsearch/index_spec.rb
+++ b/spec/jay_api/elasticsearch/index_spec.rb
@@ -205,6 +205,178 @@
     it_behaves_like 'Indexable#validate_type'
   end
 
+  describe '#update' do
+    subject(:method_call) { index.update(id:, **method_params) }
+
+    let(:id) { 'ns4AAZ8BXEjZhYMmw-8y' }
+
+    let(:method_params) { {} }
+
+    let(:successful_response) do
+      {
+        '_index' => 'elite_unit_tests',
+        '_type' => 'nested',
+        '_id' => 'ns4AAZ8BXEjZhYMmw-8y',
+        '_version' => 7,
+        'result' => 'updated',
+        '_shards' => { 'total' => 2, 'successful' => 2, 'failed' => 0 },
+        '_seq_no' => 11,
+        '_primary_term' => 1
+      }
+    end
+
+    before do
+      allow(client).to receive(:update).and_return(successful_response)
+    end
+
+    shared_examples_for '#update when the update fails' do
+      let(:error) do
+        [
+          Elasticsearch::Transport::Transport::Errors::BadRequest,
+          '400 - Bad Request'
+        ]
+      end
+
+      before do
+        allow(client).to receive(:update).and_raise(*error)
+      end
+
+      it 'raises an Elasticsearch::Transport::Transport::ServerError' do
+        expect { method_call }.to raise_error(*error)
+      end
+    end
+
+    context 'when neither doc nor script are provided' do
+      let(:method_params) { {} }
+
+      it 'raises an ArgumentError' do
+        expect { method_call }.to raise_error(
+          ArgumentError,
+          "Either 'doc' or 'script' must be provided"
+        )
+      end
+    end
+
+    context 'when a doc is provided' do
+      let(:doc) do
+        {
+          test_case: {
+            updated_at: '2026/06/30 09:54:27',
+            valid: false,
+            reason: 'The test case was invalidated due to a new firmware update'
+          }
+        }
+      end
+
+      let(:method_params) { { doc: } }
+
+      let(:expected_parameters) do
+        {
+          index: 'elite_unit_tests',
+          id: 'ns4AAZ8BXEjZhYMmw-8y',
+          body: { doc: doc }
+        }
+      end
+
+      it 'calls #update on the client with the expected parameters' do
+        expect(client).to receive(:update).with(expected_parameters)
+        method_call
+      end
+
+      context 'when the update fails' do
+        it_behaves_like '#update when the update fails'
+      end
+
+      it 'returns the expected Hash' do
+        expect(method_call).to eq(successful_response)
+      end
+    end
+
+    context 'when a script is provided' do
+      let(:script_hash) do
+        {
+          source: 'ctx._source.test_case.execution_count += params.delta;',
+          lang: 'painless',
+          params: { delta: 2 }
+        }
+      end
+
+      let(:script) do
+        instance_double(
+          JayAPI::Elasticsearch::Script,
+          to_h: script_hash
+        )
+      end
+
+      let(:method_params) { { script: } }
+
+      let(:expected_parameters) do
+        {
+          index: 'elite_unit_tests',
+          id: 'ns4AAZ8BXEjZhYMmw-8y',
+          body: { script: script_hash }
+        }
+      end
+
+      it 'calls #update on the client with the expected parameters' do
+        expect(client).to receive(:update).with(expected_parameters)
+        method_call
+      end
+
+      context 'when the update fails' do
+        it_behaves_like '#update when the update fails'
+      end
+
+      it 'returns the expected Hash' do
+        expect(method_call).to eq(successful_response)
+      end
+    end
+
+    context 'when both doc and script are provided' do
+      let(:doc) do
+        { test_case: { owner: 'robert.smith' } }
+      end
+
+      let(:script_hash) do
+        {
+          source: 'ctx._source.test_case.owner = params.owner;',
+          lang: 'painless',
+          params: { owner: 'robert.smith' }
+        }
+      end
+
+      let(:script) do
+        instance_double(
+          JayAPI::Elasticsearch::Script,
+          to_h: script_hash
+        )
+      end
+
+      let(:method_params) { { doc:, script: } }
+
+      let(:expected_parameters) do
+        {
+          index: 'elite_unit_tests',
+          id: 'ns4AAZ8BXEjZhYMmw-8y',
+          body: { doc: doc, script: script_hash }
+        }
+      end
+
+      it "calls #update on the client with the expected parameters (forwards both 'doc' and 'script')" do
+        expect(client).to receive(:update).with(expected_parameters)
+        method_call
+      end
+
+      context 'when the update fails' do
+        it_behaves_like '#update when the update fails'
+      end
+
+      it 'returns the expected Hash' do
+        expect(method_call).to eq(successful_response)
+      end
+    end
+  end
+
   describe '#settings' do
     subject(:method_call) { index.settings }
 
diff --git a/spec/jay_api/elasticsearch/query_builder/aggregations/bucket_selector_spec.rb b/spec/jay_api/elasticsearch/query_builder/aggregations/bucket_selector_spec.rb
index 4d44fc0..ad57a77 100644
--- a/spec/jay_api/elasticsearch/query_builder/aggregations/bucket_selector_spec.rb
+++ b/spec/jay_api/elasticsearch/query_builder/aggregations/bucket_selector_spec.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 require 'jay_api/elasticsearch/query_builder/aggregations/bucket_selector'
-require 'jay_api/elasticsearch/query_builder/script'
+require 'jay_api/elasticsearch/script'
 
 require_relative 'aggregation_shared'
 
@@ -16,7 +16,7 @@
 
   let(:script) do
     instance_double(
-      JayAPI::Elasticsearch::QueryBuilder::Script,
+      JayAPI::Elasticsearch::Script,
       to_h: {
         source: 'params.avgPrice > params.threshold',
         lang: 'painless',
diff --git a/spec/jay_api/elasticsearch/query_builder/aggregations/terms_spec.rb b/spec/jay_api/elasticsearch/query_builder/aggregations/terms_spec.rb
index bbb219f..890032f 100644
--- a/spec/jay_api/elasticsearch/query_builder/aggregations/terms_spec.rb
+++ b/spec/jay_api/elasticsearch/query_builder/aggregations/terms_spec.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 require 'jay_api/elasticsearch/query_builder/aggregations/terms'
-require 'jay_api/elasticsearch/query_builder/script'
+require 'jay_api/elasticsearch/script'
 
 require_relative 'aggregation_shared'
 
@@ -13,7 +13,7 @@
 
   let(:script) do
     instance_double(
-      JayAPI::Elasticsearch::QueryBuilder::Script,
+      JayAPI::Elasticsearch::Script,
       to_h: {
         source: <<~PAINLESS,
           String genre = doc['genre'].value;
@@ -107,7 +107,7 @@
     end
 
     context "when a 'script' has been given" do
-      let(:script) { instance_double(JayAPI::Elasticsearch::QueryBuilder::Script) }
+      let(:script) { instance_double(JayAPI::Elasticsearch::Script) }
 
       before do
         constructor_params.delete(:field)
diff --git a/spec/jay_api/elasticsearch/query_builder/aggregations_spec.rb b/spec/jay_api/elasticsearch/query_builder/aggregations_spec.rb
index 4e9c992..0f145e6 100644
--- a/spec/jay_api/elasticsearch/query_builder/aggregations_spec.rb
+++ b/spec/jay_api/elasticsearch/query_builder/aggregations_spec.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 require 'jay_api/elasticsearch/query_builder/aggregations'
-require 'jay_api/elasticsearch/query_builder/script'
+require 'jay_api/elasticsearch/script'
 
 RSpec.describe JayAPI::Elasticsearch::QueryBuilder::Aggregations do
   subject(:aggregations) { described_class.new }
@@ -120,7 +120,7 @@
 
       let(:script) do
         instance_double(
-          JayAPI::Elasticsearch::QueryBuilder::Script
+          JayAPI::Elasticsearch::Script
         )
       end
 
@@ -519,7 +519,7 @@
 
     let(:script) do
       instance_double(
-        JayAPI::Elasticsearch::QueryBuilder::Script
+        JayAPI::Elasticsearch::Script
       )
     end
 
diff --git a/spec/jay_api/elasticsearch/query_builder/script_spec.rb b/spec/jay_api/elasticsearch/script_spec.rb
similarity index 96%
rename from spec/jay_api/elasticsearch/query_builder/script_spec.rb
rename to spec/jay_api/elasticsearch/script_spec.rb
index 75a8158..0d59cc0 100644
--- a/spec/jay_api/elasticsearch/query_builder/script_spec.rb
+++ b/spec/jay_api/elasticsearch/script_spec.rb
@@ -1,8 +1,8 @@
 # frozen_string_literal: true
 
-require 'jay_api/elasticsearch/query_builder/script'
+require 'jay_api/elasticsearch/script'
 
-RSpec.describe JayAPI::Elasticsearch::QueryBuilder::Script do
+RSpec.describe JayAPI::Elasticsearch::Script do
   subject(:script) { described_class.new(**constructor_params) }
 
   let(:source) do