diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/ml.flush_job.json b/rest-api-spec/src/main/resources/rest-api-spec/api/ml.flush_job.json
index a10c929da9d68..9c9fe618b4c23 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/ml.flush_job.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/ml.flush_job.json
@@ -36,19 +36,19 @@
         "description": "Calculates interim results for the most recent bucket or all buckets within the latency period"
       },
       "start": {
-        "type": "string",
+        "type": "date",
         "description": "When used in conjunction with calc_interim, specifies the range of buckets on which to calculate interim results"
       },
       "end": {
-        "type": "string",
+        "type": "date",
         "description": "When used in conjunction with calc_interim, specifies the range of buckets on which to calculate interim results"
       },
       "advance_time": {
-        "type": "string",
+        "type": "date",
         "description": "Advances time to the given value generating results and updating the model for the advanced interval"
       },
       "skip_time": {
-        "type": "string",
+        "type": "date",
         "description": "Skips time to the given value without generating results or updating the model for the skipped interval"
       }
     },
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/ml.get_buckets.json b/rest-api-spec/src/main/resources/rest-api-spec/api/ml.get_buckets.json
index fd0f31de7f2db..729ff05c698f6 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/ml.get_buckets.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/ml.get_buckets.json
@@ -70,12 +70,12 @@
         "description": "specifies a max number of buckets to get"
       },
       "start": {
-        "type": "string",
+        "type": "date",
         "default": "-1",
         "description": "Start time filter for buckets"
       },
       "end": {
-        "type": "string",
+        "type": "date",
         "default": "-1",
         "description": "End time filter for buckets"
       },
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/ml.get_calendar_events.json b/rest-api-spec/src/main/resources/rest-api-spec/api/ml.get_calendar_events.json
index ebcca354b878e..397729e4c4f1c 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/ml.get_calendar_events.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/ml.get_calendar_events.json
@@ -33,7 +33,7 @@
         "description": "Get events for the job. When this option is used calendar_id must be '_all'"
       },
       "start": {
-        "type": "string",
+        "type": "date",
         "description": "Get events after this time"
       },
       "end": {
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/ml.get_influencers.json b/rest-api-spec/src/main/resources/rest-api-spec/api/ml.get_influencers.json
index 11b8ecf69507a..d1fa41e2c3541 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/ml.get_influencers.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/ml.get_influencers.json
@@ -48,12 +48,12 @@
         "description": "specifies a max number of influencers to get"
       },
       "start": {
-        "type": "string",
+        "type": "date",
         "default": "-1",
         "description": "start timestamp for the requested influencers"
       },
       "end": {
-        "type": "string",
+        "type": "date",
         "default": "-1",
         "description": "end timestamp for the requested influencers"
       },
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/ml.get_overall_buckets.json b/rest-api-spec/src/main/resources/rest-api-spec/api/ml.get_overall_buckets.json
index 4ac1aa5e82ede..f29491344dff0 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/ml.get_overall_buckets.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/ml.get_overall_buckets.json
@@ -51,11 +51,11 @@
         "description": "If true overall buckets that include interim buckets will be excluded"
       },
       "start": {
-        "type": "string",
+        "type": "date",
         "description": "Returns overall buckets with timestamps after this time"
       },
       "end": {
-        "type": "string",
+        "type": "date",
         "description": "Returns overall buckets with timestamps earlier than this time"
       },
       "allow_no_match": {
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/ml.get_records.json b/rest-api-spec/src/main/resources/rest-api-spec/api/ml.get_records.json
index f798c2a07b385..28a2d589464a7 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/ml.get_records.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/ml.get_records.json
@@ -48,12 +48,12 @@
         "description": "specifies a max number of records to get"
       },
       "start": {
-        "type": "string",
+        "type": "date",
         "default": "-1",
         "description": "Start time filter for records"
       },
       "end": {
-        "type": "string",
+        "type": "date",
         "default": "-1",
         "description": "End time filter for records"
       },
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/ml.post_data.json b/rest-api-spec/src/main/resources/rest-api-spec/api/ml.post_data.json
index 36ce0df3d5e04..0c755aab6ca2b 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/ml.post_data.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/ml.post_data.json
@@ -33,11 +33,11 @@
     },
     "params": {
       "reset_start": {
-        "type": "string",
+        "type": "date",
         "description": "Optional parameter to specify the start of the bucket resetting range"
       },
       "reset_end": {
-        "type": "string",
+        "type": "date",
         "description": "Optional parameter to specify the end of the bucket resetting range"
       }
     },
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/ml.preview_datafeed.json b/rest-api-spec/src/main/resources/rest-api-spec/api/ml.preview_datafeed.json
index e3aba8b50c6fa..92117ce20fa9b 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/ml.preview_datafeed.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/ml.preview_datafeed.json
@@ -40,11 +40,11 @@
     },
     "params": {
       "start": {
-        "type": "string",
+        "type": "date",
         "description": "The start time from where the datafeed preview should begin"
       },
       "end": {
-        "type": "string",
+        "type": "date",
         "description": "The end time when the datafeed preview should stop"
       }
     },
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/api/ml.start_datafeed.json b/rest-api-spec/src/main/resources/rest-api-spec/api/ml.start_datafeed.json
index 9d7a8b4d8cc10..931da41260d63 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/api/ml.start_datafeed.json
+++ b/rest-api-spec/src/main/resources/rest-api-spec/api/ml.start_datafeed.json
@@ -32,11 +32,11 @@
     },
     "params": {
       "start": {
-        "type": "string",
+        "type": "date",
         "description": "The start time from where the datafeed should begin"
       },
       "end": {
-        "type": "string",
+        "type": "date",
         "description": "The end time when the datafeed should stop. When not set, the datafeed continues in real time"
       },
       "timeout": {