diff --git a/encoding/openapi/testdata/builtins.json b/encoding/openapi/testdata/builtins.json
index aebb3e3..92dc87f 100644
--- a/encoding/openapi/testdata/builtins.json
+++ b/encoding/openapi/testdata/builtins.json
@@ -18,19 +18,19 @@
             "properties": {
                "timestamp1": {
                   "type": "string",
-                  "format": "dateTime"
+                  "format": "date-time"
                },
                "timestamp2": {
                   "type": "string",
-                  "format": "dateTime"
+                  "format": "date-time"
                },
                "timestamp3": {
                   "type": "string",
-                  "format": "dateTime"
+                  "format": "date-time"
                },
                "timestamp4": {
                   "type": "string",
-                  "format": "dateTime"
+                  "format": "date-time"
                },
                "date1": {
                   "type": "string",
diff --git a/encoding/openapi/testdata/oneof-funcs.json b/encoding/openapi/testdata/oneof-funcs.json
index b61f51b..6b6b548 100644
--- a/encoding/openapi/testdata/oneof-funcs.json
+++ b/encoding/openapi/testdata/oneof-funcs.json
@@ -281,8 +281,7 @@
                                  "properties": {
                                     "exact": {
                                        "description": "Randomly picked description from a set of size one.",
-                                       "type": "string",
-                                       "format": "string"
+                                       "type": "string"
                                     }
                                  }
                               },
@@ -293,8 +292,7 @@
                                  "properties": {
                                     "regex": {
                                        "description": "Randomly picked description from a set of size one.",
-                                       "type": "string",
-                                       "format": "string"
+                                       "type": "string"
                                     }
                                  }
                               }
@@ -308,8 +306,7 @@
                         "properties": {
                            "exact": {
                               "description": "Randomly picked description from a set of size one.",
-                              "type": "string",
-                              "format": "string"
+                              "type": "string"
                            }
                         }
                      },
@@ -320,8 +317,7 @@
                         "properties": {
                            "regex": {
                               "description": "Randomly picked description from a set of size one.",
-                              "type": "string",
-                              "format": "string"
+                              "type": "string"
                            }
                         }
                      }
@@ -488,8 +484,7 @@
                   "properties": {
                      "shared": {
                         "description": "Randomly picked description from a set of size one.",
-                        "type": "string",
-                        "format": "string"
+                        "type": "string"
                      },
                      "extra": {
                         "description": "Randomly picked description from a set of size one.",
diff --git a/encoding/openapi/testdata/oneof-resolve.json b/encoding/openapi/testdata/oneof-resolve.json
index 2b894b0..7130198 100644
--- a/encoding/openapi/testdata/oneof-resolve.json
+++ b/encoding/openapi/testdata/oneof-resolve.json
@@ -134,12 +134,10 @@
                         "type": "integer"
                      },
                      "exact": {
-                        "type": "string",
-                        "format": "string"
+                        "type": "string"
                      },
                      "regex": {
-                        "type": "string",
-                        "format": "string"
+                        "type": "string"
                      }
                   },
                   "allOf": [
@@ -229,12 +227,10 @@
                            "type": "integer"
                         },
                         "exact": {
-                           "type": "string",
-                           "format": "string"
+                           "type": "string"
                         },
                         "regex": {
-                           "type": "string",
-                           "format": "string"
+                           "type": "string"
                         }
                      },
                      "allOf": [
@@ -383,12 +379,10 @@
                   "type": "integer"
                },
                "exact": {
-                  "type": "string",
-                  "format": "string"
+                  "type": "string"
                },
                "regex": {
-                  "type": "string",
-                  "format": "string"
+                  "type": "string"
                }
             },
             "allOf": [
@@ -463,13 +457,7 @@
          "WithMap": {
             "type": "object",
             "properties": {
-               "shared": {
-                  "type": "object",
-                  "format": "string",
-                  "additionalProperties": {
-                     "type": "integer"
-                  }
-               },
+               "shared": {},
                "extra": {
                   "type": "integer"
                }
diff --git a/encoding/openapi/testdata/oneof.json b/encoding/openapi/testdata/oneof.json
index 9238266..66b46b3 100644
--- a/encoding/openapi/testdata/oneof.json
+++ b/encoding/openapi/testdata/oneof.json
@@ -256,8 +256,7 @@
                                  ],
                                  "properties": {
                                     "exact": {
-                                       "type": "string",
-                                       "format": "string"
+                                       "type": "string"
                                     }
                                  }
                               },
@@ -267,8 +266,7 @@
                                  ],
                                  "properties": {
                                     "regex": {
-                                       "type": "string",
-                                       "format": "string"
+                                       "type": "string"
                                     }
                                  }
                               }
@@ -281,8 +279,7 @@
                         ],
                         "properties": {
                            "exact": {
-                              "type": "string",
-                              "format": "string"
+                              "type": "string"
                            }
                         }
                      },
@@ -292,8 +289,7 @@
                         ],
                         "properties": {
                            "regex": {
-                              "type": "string",
-                              "format": "string"
+                              "type": "string"
                            }
                         }
                      }
@@ -444,8 +440,7 @@
                   ],
                   "properties": {
                      "shared": {
-                        "type": "string",
-                        "format": "string"
+                        "type": "string"
                      },
                      "extra": {
                         "type": "integer"
diff --git a/encoding/openapi/testdata/openapi-norefs.json b/encoding/openapi/testdata/openapi-norefs.json
index f5c4dfd..4a34623 100644
--- a/encoding/openapi/testdata/openapi-norefs.json
+++ b/encoding/openapi/testdata/openapi-norefs.json
@@ -65,8 +65,7 @@
                   "type": "number"
                },
                "a": {
-                  "type": "string",
-                  "format": "string"
+                  "type": "string"
                }
             },
             "oneOf": [
@@ -118,8 +117,7 @@
                "bar": {
                   "type": "array",
                   "items": {
-                     "type": "string",
-                     "format": "string"
+                     "type": "string"
                   }
                },
                "a": {
@@ -130,8 +128,7 @@
                   ]
                },
                "b": {
-                  "type": "string",
-                  "format": "string"
+                  "type": "string"
                }
             },
             "oneOf": [
@@ -169,12 +166,9 @@
             "type": "object",
             "properties": {
                "a": {
-                  "type": "string",
-                  "format": "string"
+                  "type": "string"
                },
-               "b": {
-                  "format": "string"
-               }
+               "b": {}
             },
             "oneOf": [
                {
diff --git a/encoding/openapi/testdata/openapi.json b/encoding/openapi/testdata/openapi.json
index 90bd1f5..50bcf83 100644
--- a/encoding/openapi/testdata/openapi.json
+++ b/encoding/openapi/testdata/openapi.json
@@ -77,8 +77,7 @@
                   ],
                   "properties": {
                      "a": {
-                        "type": "string",
-                        "format": "string"
+                        "type": "string"
                      }
                   }
                }
@@ -113,8 +112,7 @@
                "bar": {
                   "type": "array",
                   "items": {
-                     "type": "string",
-                     "format": "string"
+                     "type": "string"
                   }
                }
             },
@@ -139,8 +137,7 @@
                   ],
                   "properties": {
                      "b": {
-                        "type": "string",
-                        "format": "string"
+                        "type": "string"
                      }
                   }
                }
@@ -168,8 +165,7 @@
             "type": "object",
             "properties": {
                "a": {
-                  "type": "string",
-                  "format": "string"
+                  "type": "string"
                }
             },
             "oneOf": [
@@ -189,8 +185,7 @@
                   ],
                   "properties": {
                      "b": {
-                        "type": "string",
-                        "format": "string"
+                        "type": "string"
                      }
                   }
                },
diff --git a/encoding/openapi/testdata/refs.json b/encoding/openapi/testdata/refs.json
index 8c507ed..31406bf 100644
--- a/encoding/openapi/testdata/refs.json
+++ b/encoding/openapi/testdata/refs.json
@@ -14,8 +14,7 @@
             ],
             "properties": {
                "b": {
-                  "type": "string",
-                  "format": "string"
+                  "type": "string"
                }
             }
          },
@@ -47,8 +46,7 @@
             "type": "object",
             "properties": {
                "a": {
-                  "type": "string",
-                  "format": "string"
+                  "type": "string"
                }
             },
             "allOf": [
diff --git a/encoding/openapi/testdata/simple-filter.json b/encoding/openapi/testdata/simple-filter.json
index e12b2f7..fdf8708 100644
--- a/encoding/openapi/testdata/simple-filter.json
+++ b/encoding/openapi/testdata/simple-filter.json
@@ -34,7 +34,6 @@
                },
                "deprecatedField": {
                   "type": "string",
-                  "format": "string",
                   "deprecated": true
                }
             }
diff --git a/encoding/openapi/testdata/simple.json b/encoding/openapi/testdata/simple.json
index 3d5b306..4429e70 100644
--- a/encoding/openapi/testdata/simple.json
+++ b/encoding/openapi/testdata/simple.json
@@ -36,7 +36,6 @@
                },
                "deprecatedField": {
                   "type": "string",
-                  "format": "string",
                   "deprecated": true
                }
             }
diff --git a/encoding/openapi/testdata/structural.json b/encoding/openapi/testdata/structural.json
index 3e1945c..a483851 100644
--- a/encoding/openapi/testdata/structural.json
+++ b/encoding/openapi/testdata/structural.json
@@ -13,8 +13,7 @@
             "properties": {
                "stringValue": {
                   "description": "Used for values of type STRING, DNS_NAME, EMAIL_ADDRESS, and URI",
-                  "type": "string",
-                  "format": "string"
+                  "type": "string"
                },
                "int64Value": {
                   "description": "Used for values of type INT64",
@@ -38,7 +37,7 @@
                "timestampValue": {
                   "description": "Used for values of type TIMESTAMP",
                   "type": "string",
-                  "format": "dateTime"
+                  "format": "date-time"
                },
                "durationValue": {
                   "description": "Used for values of type DURATION",
@@ -55,8 +54,7 @@
                         "description": "Holds a set of name/value pairs.",
                         "type": "object",
                         "additionalProperties": {
-                           "type": "string",
-                           "format": "string"
+                           "type": "string"
                         }
                      }
                   }
@@ -119,8 +117,7 @@
                      "properties": {
                         "stringValue": {
                            "description": "Used for values of type STRING, DNS_NAME, EMAIL_ADDRESS, and URI",
-                           "type": "string",
-                           "format": "string"
+                           "type": "string"
                         },
                         "int64Value": {
                            "description": "Used for values of type INT64",
@@ -144,7 +141,7 @@
                         "timestampValue": {
                            "description": "Used for values of type TIMESTAMP",
                            "type": "string",
-                           "format": "dateTime"
+                           "format": "date-time"
                         },
                         "durationValue": {
                            "description": "Used for values of type DURATION",
@@ -161,8 +158,7 @@
                                  "description": "Holds a set of name/value pairs.",
                                  "type": "object",
                                  "additionalProperties": {
-                                    "type": "string",
-                                    "format": "string"
+                                    "type": "string"
                                  }
                               }
                            }
@@ -224,8 +220,7 @@
                   "description": "Holds a set of name/value pairs.",
                   "type": "object",
                   "additionalProperties": {
-                     "type": "string",
-                     "format": "string"
+                     "type": "string"
                   }
                }
             }