diff --git a/elasticsearch-api/lib/elasticsearch/api/actions/inference/put_custom.rb b/elasticsearch-api/lib/elasticsearch/api/actions/inference/put_custom.rb
new file mode 100644
index 0000000000..a8937cbb55
--- /dev/null
+++ b/elasticsearch-api/lib/elasticsearch/api/actions/inference/put_custom.rb
@@ -0,0 +1,112 @@
+# Licensed to Elasticsearch B.V. under one or more contributor
+# license agreements. See the NOTICE file distributed with
+# this work for additional information regarding copyright
+# ownership. Elasticsearch B.V. licenses this file to you under
+# the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+# This code was automatically generated from the Elasticsearch Specification
+# See https://github.com/elastic/elasticsearch-specification
+# See Elasticsearch::ES_SPECIFICATION_COMMIT for commit hash.
+module Elasticsearch
+  module API
+    module Inference
+      module Actions
+        # Create a custom inference endpoint.
+        # The custom service gives more control over how to interact with external inference services that aren't explicitly supported through dedicated integrations.
+        # The custom service gives you the ability to define the headers, url, query parameters, request body, and secrets.
+        # The custom service supports the template replacement functionality, which enables you to define a template that can be replaced with the value associated with that key.
+        # Templates are portions of a string that start with `${` and end with `}`.
+        # The parameters `secret_parameters` and `task_settings` are checked for keys for template replacement. Template replacement is supported in the `request`, `headers`, `url`, and `query_parameters`.
+        # If the definition (key) is not found for a template, an error message is returned.
+        # In case of an endpoint definition like the following:
+        #
+        # ```
+        # PUT _inference/text_embedding/test-text-embedding
+        # {
+        #   "service": "custom",
+        #   "service_settings": {
+        #      "secret_parameters": {
+        #           "api_key": "<some api key>"
+        #      },
+        #      "url": "...endpoints.huggingface.cloud/v1/embeddings",
+        #      "headers": {
+        #          "Authorization": "Bearer ${api_key}",
+        #          "Content-Type": "application/json"
+        #      },
+        #      "request": "{\"input\": ${input}}",
+        #      "response": {
+        #          "json_parser": {
+        #              "text_embeddings":"$.data[*].embedding[*]"
+        #          }
+        #      }
+        #   }
+        # }
+        # ```
+        #
+        # To replace `${api_key}` the `secret_parameters` and `task_settings` are checked for a key named `api_key`.
+        #
+        # @option arguments [String] :task_type The type of the inference task that the model will perform. (*Required*)
+        # @option arguments [String] :custom_inference_id The unique identifier of the inference endpoint. (*Required*)
+        # @option arguments [Boolean] :error_trace When set to `true` Elasticsearch will include the full stack trace of errors
+        #  when they occur.
+        # @option arguments [String, Array<String>] :filter_path Comma-separated list of filters in dot notation which reduce the response
+        #  returned by Elasticsearch.
+        # @option arguments [Boolean] :human When set to `true` will return statistics in a format suitable for humans.
+        #  For example `"exists_time": "1h"` for humans and
+        #  `"exists_time_in_millis": 3600000` for computers. When disabled the human
+        #  readable values will be omitted. This makes sense for responses being consumed
+        #  only by machines.
+        # @option arguments [Boolean] :pretty If set to `true` the returned JSON will be "pretty-formatted". Only use
+        #  this option for debugging only.
+        # @option arguments [Hash] :headers Custom HTTP headers
+        # @option arguments [Hash] :body request body
+        #
+        # @see https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-inference-put-custom
+        #
+        def put_custom(arguments = {})
+          request_opts = { endpoint: arguments[:endpoint] || 'inference.put_custom' }
+
+          defined_params = [:task_type, :custom_inference_id].each_with_object({}) do |variable, set_variables|
+            set_variables[variable] = arguments[variable] if arguments.key?(variable)
+          end
+          request_opts[:defined_params] = defined_params unless defined_params.empty?
+
+          raise ArgumentError, "Required argument 'task_type' missing" unless arguments[:task_type]
+
+          unless arguments[:custom_inference_id]
+            raise ArgumentError,
+                  "Required argument 'custom_inference_id' missing"
+          end
+
+          arguments = arguments.clone
+          headers = arguments.delete(:headers) || {}
+
+          body = arguments.delete(:body)
+
+          _task_type = arguments.delete(:task_type)
+
+          _custom_inference_id = arguments.delete(:custom_inference_id)
+
+          method = Elasticsearch::API::HTTP_PUT
+          path   = "_inference/#{Utils.listify(_task_type)}/#{Utils.listify(_custom_inference_id)}"
+          params = Utils.process_params(arguments)
+
+          Elasticsearch::API::Response.new(
+            perform_request(method, path, params, body, headers, request_opts)
+          )
+        end
+      end
+    end
+  end
+end
diff --git a/elasticsearch-api/spec/unit/actions/inference/put_custom_spec.rb b/elasticsearch-api/spec/unit/actions/inference/put_custom_spec.rb
new file mode 100644
index 0000000000..a409676f1b
--- /dev/null
+++ b/elasticsearch-api/spec/unit/actions/inference/put_custom_spec.rb
@@ -0,0 +1,36 @@
+# Licensed to Elasticsearch B.V. under one or more contributor
+# license agreements. See the NOTICE file distributed with
+# this work for additional information regarding copyright
+# ownership. Elasticsearch B.V. licenses this file to you under
+# the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+require 'spec_helper'
+
+describe 'client#inference.put_custom' do
+  let(:expected_args) do
+    [
+      'PUT',
+      '_inference/foo/baz',
+      {},
+      nil,
+      {},
+      { defined_params: { custom_inference_id: 'baz', task_type: 'foo' },
+        endpoint: 'inference.put_custom' }
+    ]
+  end
+
+  it 'performs the request' do
+    expect(client_double.inference.put_custom(task_type: 'foo', custom_inference_id: 'baz')).to be_a Elasticsearch::API::Response
+  end
+end