diff --git a/doc/swagger.json b/doc/swagger.json
index 66186d7..14ebd06 100644
--- a/doc/swagger.json
+++ b/doc/swagger.json
@@ -1,124 +1,188 @@
-swagger: "2.0"
-info:
-  description: "A simple endpoint to send email messages"
-  version: "0.1"
-  title: "EXPMail"
-  contact:
-    email: "support@kumi.systems"
-host: "expmail.kumi.live"
-tags:
-- name: "sending"
-  description: "Sending out an email"
-schemes:
-- "https"
-paths:
-  /sender.php:
-    post:
-      tags:
-      - "sending"
-      summary: "Send out an email"
-      operationId: "sendMail"
-      consumes:
-      - "application/json"
-      produces:
-      - "application/json"
-      parameters:
-      - in: "body"
-        name: "data"
-        description: "Object defining the email message to be sent"
-        required: true
-        schema:
-          $ref: "#/definitions/Mail"
-      responses:
-        200:
-          description: "The request was received and processed."
-          schema:
-            type: "object"
-            properties:
-              status:
-                type: "string"
-                description: "\"Success\" if message was successfully sent, else \"error\""
-              error:
-                type: "string"
-                description: "Error message, only included if an error has occurred"
-definitions:
-  Placeholder:
-    type: "object"
-    required: ["name"]
-    properties:
-      name:
-        type: "string"
-        description: "Name of the placeholder - will be converted to ALL CAPS by the server if it isn't already"
-      value:
-        type: "string"
-        description: "Value to insert into placeholder"
-  Attachment:
-    type: "object"
-    required: ["url"]
-    properties:
-      url:
-        type: "string"
-        format: "url"
-        description: "URL from where to fetch the file to attach"
-      filename:
-        type: "string"
-        description: "File name to use for email attachment. If not set, defaults to name from Content-Disposition header of URL if it exists, else the base name of the URL."
-  Recipient:
-    type: "object"
-    required: ["email"]
-    properties:
-      email:
-        type: "string"
-        format: "email"
-        description: "Email address of the recipient"
-      name:
-        type: "string"
-        description: "Name of the recipient"
-  Mail:
-    type: "object"
-    required: ["recipients", "key"]
-    properties:
-      subject:
-        type: "string"
-        description: "Subject of the email"
-      html:
-        type: "string"
-        description: "String containing the HTML content of the email. Takes precedence over `htmlurl` if provided. If both `html` and `text` or `texturl` are provided, will create a multi-part MIME message."
-      htmlurl:
-        type: "string"
-        description: "String containing the URL to a file containing the HTML content of the email. Ignored (but still validated) if `html` if provided. If both `htmlurl` and `text` or `texturl` are provided, will create a multi-part MIME message."
-      text:
-        type: "string"
-        description: "String containing the plain text content of the email. Takes precedence over `texturl` if provided. If both `text` and `html` or `htmlurl` are provided, will create a multi-part MIME message."
-      texturl:
-        type: "string"
-        description: "String containing the URL to a file containing the plain text content of the email. Ignored (but still validated) if `text` is provided. If both `texturl` and `html` or `htmlurl` are provided, will create a multi-part MIME message."
-      recipients:
-        type: "array"
-        description: "Array of `Recipient` objects to be used as \"To:\" addresses for the email"
-        items:
-          $ref: "#/definitions/Recipient"
-      ccs:
-        type: "array"
-        description: "Array of `Recipient` objects to be used as \"CC:\" addresses for the email"
-        items:
-          $ref: "#/definitions/Recipient"
-      bccs:
-        type: "array"
-        description: "Array of `Recipient` objects to be used as \"BCC:\" addresses for the email"
-        items:
-          $ref: "#/definitions/Recipient"
-      attachments:
-        type: "array"
-        description: "Array of `Attachment` objects to be attached to the email"
-        items:
-          $ref: "#/definitions/Attachment"
-      placeholders:
-        type: "array"
-        description: "Array of `Placeholder` objects. Any occurrences of `{PLACEHOLDER_NAME}` (`name` in all caps enclosed with curly brackets) in the email's HTML or plain text will be replaced by `value`."
-        items:
-          $ref: "#/definitions/Placeholder"
-      key:
-        type: "string"
-        description: "API key to authenticate request with"
-
+{
+  "openapi": "3.0.0",
+  "info": {
+    "description": "A simple endpoint to send email messages",
+    "version": "0.1",
+    "title": "EXPMail",
+    "contact": {
+      "email": "support@kumi.systems"
+    }
+  },
+  "tags": [
+    {
+      "name": "sending",
+      "description": "Sending out an email"
+    }
+  ],
+  "paths": {
+    "/sender.php": {
+      "post": {
+        "tags": [
+          "sending"
+        ],
+        "summary": "Send out an email",
+        "operationId": "sendMail",
+        "requestBody": {
+          "content": {
+            "application/json": {
+              "schema": {
+                "$ref": "#/components/schemas/Mail"
+              }
+            }
+          },
+          "description": "Object defining the email message to be sent",
+          "required": true
+        },
+        "responses": {
+          "200": {
+            "description": "The request was received and processed.",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "object",
+                  "properties": {
+                    "status": {
+                      "type": "string",
+                      "description": "\"Success\" if message was successfully sent, else \"error\""
+                    },
+                    "error": {
+                      "type": "string",
+                      "description": "Error message, only included if an error has occurred"
+                    }
+                  }
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  },
+  "servers": [
+    {
+      "url": "https://expmail.kumi.live"
+    }
+  ],
+  "components": {
+    "schemas": {
+      "Placeholder": {
+        "type": "object",
+        "required": [
+          "name"
+        ],
+        "properties": {
+          "name": {
+            "type": "string",
+            "description": "Name of the placeholder - will be converted to ALL CAPS by the server if it isn't already"
+          },
+          "value": {
+            "type": "string",
+            "description": "Value to insert into placeholder"
+          }
+        }
+      },
+      "Attachment": {
+        "type": "object",
+        "required": [
+          "url"
+        ],
+        "properties": {
+          "url": {
+            "type": "string",
+            "format": "url",
+            "description": "URL from where to fetch the file to attach"
+          },
+          "filename": {
+            "type": "string",
+            "description": "File name to use for email attachment. If not set, defaults to name from Content-Disposition header of URL if it exists, else the base name of the URL."
+          }
+        }
+      },
+      "Recipient": {
+        "type": "object",
+        "required": [
+          "email"
+        ],
+        "properties": {
+          "email": {
+            "type": "string",
+            "format": "email",
+            "description": "Email address of the recipient"
+          },
+          "name": {
+            "type": "string",
+            "description": "Name of the recipient"
+          }
+        }
+      },
+      "Mail": {
+        "type": "object",
+        "required": [
+          "recipients",
+          "key"
+        ],
+        "properties": {
+          "subject": {
+            "type": "string",
+            "description": "Subject of the email"
+          },
+          "html": {
+            "type": "string",
+            "description": "String containing the HTML content of the email. Takes precedence over `htmlurl` if provided. If both `html` and `text` or `texturl` are provided, will create a multi-part MIME message."
+          },
+          "htmlurl": {
+            "type": "string",
+            "description": "String containing the URL to a file containing the HTML content of the email. Ignored (but still validated) if `html` if provided. If both `htmlurl` and `text` or `texturl` are provided, will create a multi-part MIME message."
+          },
+          "text": {
+            "type": "string",
+            "description": "String containing the plain text content of the email. Takes precedence over `texturl` if provided. If both `text` and `html` or `htmlurl` are provided, will create a multi-part MIME message."
+          },
+          "texturl": {
+            "type": "string",
+            "description": "String containing the URL to a file containing the plain text content of the email. Ignored (but still validated) if `text` is provided. If both `texturl` and `html` or `htmlurl` are provided, will create a multi-part MIME message."
+          },
+          "recipients": {
+            "type": "array",
+            "description": "Array of `Recipient` objects to be used as \"To:\" addresses for the email",
+            "items": {
+              "$ref": "#/components/schemas/Recipient"
+            }
+          },
+          "ccs": {
+            "type": "array",
+            "description": "Array of `Recipient` objects to be used as \"CC:\" addresses for the email",
+            "items": {
+              "$ref": "#/components/schemas/Recipient"
+            }
+          },
+          "bccs": {
+            "type": "array",
+            "description": "Array of `Recipient` objects to be used as \"BCC:\" addresses for the email",
+            "items": {
+              "$ref": "#/components/schemas/Recipient"
+            }
+          },
+          "attachments": {
+            "type": "array",
+            "description": "Array of `Attachment` objects to be attached to the email",
+            "items": {
+              "$ref": "#/components/schemas/Attachment"
+            }
+          },
+          "placeholders": {
+            "type": "array",
+            "description": "Array of `Placeholder` objects. Any occurrences of `{PLACEHOLDER_NAME}` (`name` in all caps enclosed with curly brackets) in the email's HTML or plain text will be replaced by `value`.",
+            "items": {
+              "$ref": "#/components/schemas/Placeholder"
+            }
+          },
+          "key": {
+            "type": "string",
+            "description": "API key to authenticate request with"
+          }
+        }
+      }
+    }
+  }
+}
\ No newline at end of file