diff --git a/tests/test_app.py b/tests/test_app.py
index 18b8ef45..c3f5b2e8 100644
--- a/tests/test_app.py
+++ b/tests/test_app.py
@@ -1,8 +1,13 @@
 from apispec.utils import validate_spec
+import json
+import jsonschema
+import os
+
 from openflexure_microscope.api.app import api_microscope, app, labthing
 from openflexure_microscope.camera.base import BaseCamera
 from openflexure_microscope.microscope import Microscope
 from openflexure_microscope.stage.base import BaseStage
+from labthings.json import encode_json
 
 
 def test_app_creation():
@@ -17,3 +22,24 @@ def test_microscope_creation():
 
 def test_openapi_valid():
     assert validate_spec(labthing.spec)
+
+def test_thing_description_valid():
+    # TODO: it would be nice to put this into LabThings
+    # First load the schema from file and check it validates
+    schema_fname = os.path.join(
+        os.path.dirname(__file__), 
+        "w3c_td_schema.json"
+    )
+    schema = json.load(open(schema_fname, "r"))
+    jsonschema.Draft7Validator.check_schema(schema)
+
+    # Build a TD dictionary
+    with labthing.app.test_request_context():
+            td_dict = labthing.thing_description.to_dict()
+
+    # Allow our LabThingsJSONEncoder to encode the RD
+    td_json = encode_json(td_dict)
+    # Decode the JSON back into a primitive dictionary
+    td_json_dict = json.loads(td_json)
+    # Validate
+    jsonschema.validate(instance=td_json_dict, schema=schema)
\ No newline at end of file
diff --git a/tests/w3c_td_schema.json b/tests/w3c_td_schema.json
new file mode 100644
index 00000000..62194083
--- /dev/null
+++ b/tests/w3c_td_schema.json
@@ -0,0 +1,1035 @@
+{
+    "title": "WoT TD Schema - 16 October 2019",
+    "description": "JSON Schema for validating TD instances against the TD model. TD instances can be with or without terms that have default values",
+    "$schema ": "http://json-schema.org/draft-07/schema#",
+    "definitions": {
+        "anyUri": {
+            "type": "string",
+            "format": "iri-reference"
+        },
+        "description": {
+            "type": "string"
+        },
+        "descriptions": {
+            "type": "object",
+            "additionalProperties": {
+                "type": "string"
+            }
+        },
+        "title": {
+            "type": "string"
+        },
+        "titles": {
+            "type": "object",
+            "additionalProperties": {
+                "type": "string"
+            }
+        },
+        "security": {
+            "oneOf": [{
+                    "type": "array",
+                    "items": {
+                        "type": "string"
+                    }
+                },
+                {
+                    "type": "string"
+                }
+            ]
+        },
+        "scopes": {
+            "oneOf": [{
+                    "type": "array",
+                    "items": {
+                        "type": "string"
+                    }
+                },
+                {
+                    "type": "string"
+                }
+            ]
+        },
+        "subprotocol": {
+            "type": "string",
+            "enum": [
+                "longpoll",
+                "websub",
+                "sse"
+            ]
+        },
+        "thing-context-w3c-uri": {
+            "type": "string",
+            "enum": [
+                "https://www.w3.org/2019/wot/td/v1"
+            ]
+        },
+        "thing-context": {
+            "oneOf": [{
+                    "type": "array",
+                    "items": [{
+                        "$ref": "#/definitions/thing-context-w3c-uri"
+                    }],
+                    "additionalItems": {
+                        "anyOf": [{
+                                "$ref": "#/definitions/anyUri"
+                            },
+                            {
+                                "type": "object"
+                            }
+                        ]
+                    }
+                },
+                {
+                    "$ref": "#/definitions/thing-context-w3c-uri"
+                }
+            ]
+        },
+        "type_declaration": {
+            "oneOf": [{
+                    "type": "string"
+                },
+                {
+                    "type": "array",
+                    "items": {
+                        "type": "string"
+                    }
+                }
+            ]
+        },
+        "dataSchema": {
+            "type": "object",
+            "properties": {
+                "@type": {
+                    "$ref": "#/definitions/type_declaration"
+                },
+                "description": {
+                    "$ref": "#/definitions/description"
+                },
+                "title": {
+                    "$ref": "#/definitions/title"
+                },
+                "descriptions": {
+                    "$ref": "#/definitions/descriptions"
+                },
+                "titles": {
+                    "$ref": "#/definitions/titles"
+                },
+                "writeOnly": {
+                    "type": "boolean"
+                },
+                "readOnly": {
+                    "type": "boolean"
+                },
+                "oneOf": {
+                    "type": "array",
+                    "items": {
+                        "$ref": "#/definitions/dataSchema"
+                    }
+                },
+                "unit": {
+                    "type": "string"
+                },
+                "enum": {
+                    "type": "array",
+                    "minItems": 1,
+                    "uniqueItems": true
+                },
+                "format": {
+                    "type": "string"
+                },
+                "const": {},
+                "type": {
+                    "type": "string",
+                    "enum": [
+                        "boolean",
+                        "integer",
+                        "number",
+                        "string",
+                        "object",
+                        "array",
+                        "null"
+                    ]
+                },
+                "items": {
+                    "oneOf": [{
+                            "$ref": "#/definitions/dataSchema"
+                        },
+                        {
+                            "type": "array",
+                            "items": {
+                                "$ref": "#/definitions/dataSchema"
+                            }
+                        }
+                    ]
+                },
+                "maxItems": {
+                    "type": "integer",
+                    "minimum": 0
+                },
+                "minItems": {
+                    "type": "integer",
+                    "minimum": 0
+                },
+                "minimum": {
+                    "type": "number"
+                },
+                "maximum": {
+                    "type": "number"
+                },
+                "properties": {
+                    "additionalProperties": {
+                        "$ref": "#/definitions/dataSchema"
+                    }
+                },
+                "required": {
+                    "type": "array",
+                    "items": {
+                        "type": "string"
+                    }
+                }
+            }
+        },
+        "form_element_property": {
+            "type": "object",
+            "properties": {
+                "op": {
+                    "oneOf": [{
+                            "type": "string",
+                            "enum": [
+                                "readproperty",
+                                "writeproperty",
+                                "observeproperty",
+                                "unobserveproperty"
+                            ]
+                        },
+                        {
+                            "type": "array",
+                            "items": {
+                                "type": "string",
+                                "enum": [
+                                    "readproperty",
+                                    "writeproperty",
+                                    "observeproperty",
+                                    "unobserveproperty"
+                                ]
+                            }
+                        }
+                    ]
+                },
+                "href": {
+                    "$ref": "#/definitions/anyUri"
+                },
+                "contentType": {
+                    "type": "string"
+                },
+                "contentCoding": {
+                    "type": "string"
+                },
+                "subprotocol": {
+                    "$ref": "#/definitions/subprotocol"
+                },
+                "security": {
+                    "$ref": "#/definitions/security"
+                },
+                "scopes": {
+                    "$ref": "#/definitions/scopes"
+                },
+                "response": {
+                    "type": "object",
+                    "properties": {
+                        "contentType": {
+                            "type": "string"
+                        }
+                    }
+                }
+            },
+            "required": [
+                "href"
+            ],
+            "additionalProperties": true
+        },
+        "form_element_action": {
+            "type": "object",
+            "properties": {
+                "op": {
+                    "oneOf": [{
+                            "type": "string",
+                            "enum": [
+                                "invokeaction"
+                            ]
+                        },
+                        {
+                            "type": "array",
+                            "items": {
+                                "type": "string",
+                                "enum": [
+                                    "invokeaction"
+                                ]
+                            }
+                        }
+                    ]
+                },
+                "href": {
+                    "$ref": "#/definitions/anyUri"
+                },
+                "contentType": {
+                    "type": "string"
+                },
+                "contentCoding": {
+                    "type": "string"
+                },
+                "subprotocol": {
+                    "$ref": "#/definitions/subprotocol"
+                },
+                "security": {
+                    "$ref": "#/definitions/security"
+                },
+                "scopes": {
+                    "$ref": "#/definitions/scopes"
+                },
+                "response": {
+                    "type": "object",
+                    "properties": {
+                        "contentType": {
+                            "type": "string"
+                        }
+                    }
+                }
+            },
+            "required": [
+                "href"
+            ],
+            "additionalProperties": true
+        },
+        "form_element_event": {
+            "type": "object",
+            "properties": {
+                "op": {
+                    "oneOf": [{
+                            "type": "string",
+                            "enum": [
+                                "subscribeevent",
+                                "unsubscribeevent"
+                            ]
+                        },
+                        {
+                            "type": "array",
+                            "items": {
+                                "type": "string",
+                                "enum": [
+                                    "subscribeevent",
+                                    "unsubscribeevent"
+                                ]
+                            }
+                        }
+                    ]
+                },
+                "href": {
+                    "$ref": "#/definitions/anyUri"
+                },
+                "contentType": {
+                    "type": "string"
+                },
+                "contentCoding": {
+                    "type": "string"
+                },
+                "subprotocol": {
+                    "$ref": "#/definitions/subprotocol"
+                },
+                "security": {
+                    "$ref": "#/definitions/security"
+                },
+                "scopes": {
+                    "$ref": "#/definitions/scopes"
+                },
+                "response": {
+                    "type": "object",
+                    "properties": {
+                        "contentType": {
+                            "type": "string"
+                        }
+                    }
+                }
+            },
+            "required": [
+                "href"
+            ],
+            "additionalProperties": true
+        },
+        "form_element_root": {
+            "type": "object",
+            "properties": {
+                "op": {
+                    "oneOf": [{
+                            "type": "string",
+                            "enum": [
+                                "readallproperties",
+                                "writeallproperties",
+                                "readmultipleproperties",
+                                "writemultipleproperties"
+                            ]
+                        },
+                        {
+                            "type": "array",
+                            "items": {
+                                "type": "string",
+                                "enum": [
+                                    "readallproperties",
+                                    "writeallproperties",
+                                    "readmultipleproperties",
+                                    "writemultipleproperties"
+                                ]
+                            }
+                        }
+                    ]
+                },
+                "href": {
+                    "$ref": "#/definitions/anyUri"
+                },
+                "contentType": {
+                    "type": "string"
+                },
+                "contentCoding": {
+                    "type": "string"
+                },
+                "subprotocol": {
+                    "$ref": "#/definitions/subprotocol"
+                },
+                "security": {
+                    "$ref": "#/definitions/security"
+                },
+                "scopes": {
+                    "$ref": "#/definitions/scopes"
+                },
+                "response": {
+                    "type": "object",
+                    "properties": {
+                        "contentType": {
+                            "type": "string"
+                        }
+                    }
+                }
+            },
+            "required": [
+                "href"
+            ],
+            "additionalProperties": true
+        },
+        "property_element": {
+            "type": "object",
+            "properties": {
+                "@type": {
+                    "$ref": "#/definitions/type_declaration"
+                },
+                "description": {
+                    "$ref": "#/definitions/description"
+                },
+                "descriptions": {
+                    "$ref": "#/definitions/descriptions"
+                },
+                "title": {
+                    "$ref": "#/definitions/title"
+                },
+                "titles": {
+                    "$ref": "#/definitions/titles"
+                },
+                "forms": {
+                    "type": "array",
+                    "minItems": 1,
+                    "items": {
+                        "$ref": "#/definitions/form_element_property"
+                    }
+                },
+                "uriVariables": {
+                    "type": "object",
+                    "additionalProperties": {
+                        "$ref": "#/definitions/dataSchema"
+                    }
+                },
+                "observable": {
+                    "type": "boolean"
+                },
+                "writeOnly": {
+                    "type": "boolean"
+                },
+                "readOnly": {
+                    "type": "boolean"
+                },
+                "oneOf": {
+                    "type": "array",
+                    "items": {
+                        "$ref": "#/definitions/dataSchema"
+                    }
+                },
+                "unit": {
+                    "type": "string"
+                },
+                "enum": {
+                    "type": "array",
+                    "minItems": 1,
+                    "uniqueItems": true
+                },
+                "format": {
+                    "type": "string"
+                },
+                "const": {},
+                "type": {
+                    "type": "string",
+                    "enum": [
+                        "boolean",
+                        "integer",
+                        "number",
+                        "string",
+                        "object",
+                        "array",
+                        "null"
+                    ]
+                },
+                "items": {
+                    "oneOf": [{
+                            "$ref": "#/definitions/dataSchema"
+                        },
+                        {
+                            "type": "array",
+                            "items": {
+                                "$ref": "#/definitions/dataSchema"
+                            }
+                        }
+                    ]
+                },
+                "maxItems": {
+                    "type": "integer",
+                    "minimum": 0
+                },
+                "minItems": {
+                    "type": "integer",
+                    "minimum": 0
+                },
+                "minimum": {
+                    "type": "number"
+                },
+                "maximum": {
+                    "type": "number"
+                },
+                "properties": {
+                    "additionalProperties": {
+                        "$ref": "#/definitions/dataSchema"
+                    }
+                },
+                "required": {
+                    "type": "array",
+                    "items": {
+                        "type": "string"
+                    }
+                }
+            },
+            "required": [
+                "forms"
+            ],
+            "additionalProperties": true
+        },
+        "action_element": {
+            "type": "object",
+            "properties": {
+                "@type": {
+                    "$ref": "#/definitions/type_declaration"
+                },
+                "description": {
+                    "$ref": "#/definitions/description"
+                },
+                "descriptions": {
+                    "$ref": "#/definitions/descriptions"
+                },
+                "title": {
+                    "$ref": "#/definitions/title"
+                },
+                "titles": {
+                    "$ref": "#/definitions/titles"
+                },
+                "forms": {
+                    "type": "array",
+                    "minItems": 1,
+                    "items": {
+                        "$ref": "#/definitions/form_element_action"
+                    }
+                },
+                "uriVariables": {
+                    "type": "object",
+                    "additionalProperties": {
+                        "$ref": "#/definitions/dataSchema"
+                    }
+                },
+                "input": {
+                    "$ref": "#/definitions/dataSchema"
+                },
+                "output": {
+                    "$ref": "#/definitions/dataSchema"
+                },
+                "safe": {
+                    "type": "boolean"
+                },
+                "idempotent": {
+                    "type": "boolean"
+                }
+            },
+            "required": [
+                "forms"
+            ],
+            "additionalProperties": true
+        },
+        "event_element": {
+            "type": "object",
+            "properties": {
+                "@type": {
+                    "$ref": "#/definitions/type_declaration"
+                },
+                "description": {
+                    "$ref": "#/definitions/description"
+                },
+                "descriptions": {
+                    "$ref": "#/definitions/descriptions"
+                },
+                "title": {
+                    "$ref": "#/definitions/title"
+                },
+                "titles": {
+                    "$ref": "#/definitions/titles"
+                },
+                "forms": {
+                    "type": "array",
+                    "minItems": 1,
+                    "items": {
+                        "$ref": "#/definitions/form_element_event"
+                    }
+                },
+                "uriVariables": {
+                    "type": "object",
+                    "additionalProperties": {
+                        "$ref": "#/definitions/dataSchema"
+                    }
+                },
+                "subscription": {
+                    "$ref": "#/definitions/dataSchema"
+                },
+                "data": {
+                    "$ref": "#/definitions/dataSchema"
+                },
+                "cancellation": {
+                    "$ref": "#/definitions/dataSchema"
+                }
+            },
+            "required": [
+                "forms"
+            ],
+            "additionalProperties": true
+        },
+        "link_element": {
+            "type": "object",
+            "properties": {
+                "href": {
+                    "$ref": "#/definitions/anyUri"
+                },
+                "type": {
+                    "type": "string"
+                },
+                "rel": {
+                    "type": "string"
+                },
+                "anchor": {
+                    "$ref": "#/definitions/anyUri"
+                }
+            },
+            "required": [
+                "href"
+            ],
+            "additionalProperties": true
+        },
+        "securityScheme": {
+            "oneOf": [{
+                    "type": "object",
+                    "properties": {
+                        "@type": {
+                            "$ref": "#/definitions/type_declaration"
+                        },
+                        "description": {
+                            "$ref": "#/definitions/description"
+                        },
+                        "descriptions": {
+                            "$ref": "#/definitions/descriptions"
+                        },
+                        "proxy": {
+                            "$ref": "#/definitions/anyUri"
+                        },
+                        "scheme": {
+                            "type": "string",
+                            "enum": [
+                                "nosec"
+                            ]
+                        }
+                    },
+                    "required": [
+                        "scheme"
+                    ]
+                },
+                {
+                    "type": "object",
+                    "properties": {
+                        "@type": {
+                            "$ref": "#/definitions/type_declaration"
+                        },
+                        "description": {
+                            "$ref": "#/definitions/description"
+                        },
+                        "descriptions": {
+                            "$ref": "#/definitions/descriptions"
+                        },
+                        "proxy": {
+                            "$ref": "#/definitions/anyUri"
+                        },
+                        "scheme": {
+                            "type": "string",
+                            "enum": [
+                                "basic"
+                            ]
+                        },
+                        "in": {
+                            "type": "string",
+                            "enum": [
+                                "header",
+                                "query",
+                                "body",
+                                "cookie"
+                            ]
+                        },
+                        "name": {
+                            "type": "string"
+                        }
+                    },
+                    "required": [
+                        "scheme"
+                    ]
+                },
+                {
+                    "type": "object",
+                    "properties": {
+                        "@type": {
+                            "$ref": "#/definitions/type_declaration"
+                        },
+                        "description": {
+                            "$ref": "#/definitions/description"
+                        },
+                        "descriptions": {
+                            "$ref": "#/definitions/descriptions"
+                        },
+                        "proxy": {
+                            "$ref": "#/definitions/anyUri"
+                        },
+                        "scheme": {
+                            "type": "string",
+                            "enum": [
+                                "digest"
+                            ]
+                        },
+                        "qop": {
+                            "type": "string",
+                            "enum": [
+                                "auth",
+                                "auth-int"
+                            ]
+                        },
+                        "in": {
+                            "type": "string",
+                            "enum": [
+                                "header",
+                                "query",
+                                "body",
+                                "cookie"
+                            ]
+                        },
+                        "name": {
+                            "type": "string"
+                        }
+                    },
+                    "required": [
+                        "scheme"
+                    ]
+                },
+                {
+                    "type": "object",
+                    "properties": {
+                        "@type": {
+                            "$ref": "#/definitions/type_declaration"
+                        },
+                        "description": {
+                            "$ref": "#/definitions/description"
+                        },
+                        "descriptions": {
+                            "$ref": "#/definitions/descriptions"
+                        },
+                        "proxy": {
+                            "$ref": "#/definitions/anyUri"
+                        },
+                        "scheme": {
+                            "type": "string",
+                            "enum": [
+                                "apikey"
+                            ]
+                        },
+                        "in": {
+                            "type": "string",
+                            "enum": [
+                                "header",
+                                "query",
+                                "body",
+                                "cookie"
+                            ]
+                        },
+                        "name": {
+                            "type": "string"
+                        }
+                    },
+                    "required": [
+                        "scheme"
+                    ]
+                },
+                {
+                    "type": "object",
+                    "properties": {
+                        "@type": {
+                            "$ref": "#/definitions/type_declaration"
+                        },
+                        "description": {
+                            "$ref": "#/definitions/description"
+                        },
+                        "descriptions": {
+                            "$ref": "#/definitions/descriptions"
+                        },
+                        "proxy": {
+                            "$ref": "#/definitions/anyUri"
+                        },
+                        "scheme": {
+                            "type": "string",
+                            "enum": [
+                                "bearer"
+                            ]
+                        },
+                        "authorization": {
+                            "$ref": "#/definitions/anyUri"
+                        },
+                        "alg": {
+                            "type": "string"
+                        },
+                        "format": {
+                            "type": "string"
+                        },
+                        "in": {
+                            "type": "string",
+                            "enum": [
+                                "header",
+                                "query",
+                                "body",
+                                "cookie"
+                            ]
+                        },
+                        "name": {
+                            "type": "string"
+                        }
+                    },
+                    "required": [
+                        "scheme"
+                    ]
+                },
+                {
+                    "type": "object",
+                    "properties": {
+                        "@type": {
+                            "$ref": "#/definitions/type_declaration"
+                        },
+                        "description": {
+                            "$ref": "#/definitions/description"
+                        },
+                        "descriptions": {
+                            "$ref": "#/definitions/descriptions"
+                        },
+                        "proxy": {
+                            "$ref": "#/definitions/anyUri"
+                        },
+                        "scheme": {
+                            "type": "string",
+                            "enum": [
+                                "psk"
+                            ]
+                        },
+                        "identity": {
+                            "type": "string"
+                        }
+                    },
+                    "required": [
+                        "scheme"
+                    ]
+                },
+                {
+                    "type": "object",
+                    "properties": {
+                        "@type": {
+                            "$ref": "#/definitions/type_declaration"
+                        },
+                        "description": {
+                            "$ref": "#/definitions/description"
+                        },
+                        "descriptions": {
+                            "$ref": "#/definitions/descriptions"
+                        },
+                        "proxy": {
+                            "$ref": "#/definitions/anyUri"
+                        },
+                        "scheme": {
+                            "type": "string",
+                            "enum": [
+                                "oauth2"
+                            ]
+                        },
+                        "authorization": {
+                            "$ref": "#/definitions/anyUri"
+                        },
+                        "token": {
+                            "$ref": "#/definitions/anyUri"
+                        },
+                        "refresh": {
+                            "$ref": "#/definitions/anyUri"
+                        },
+                        "scopes": {
+                            "oneOf": [{
+                                    "type": "array",
+                                    "items": {
+                                        "type": "string"
+                                    }
+                                },
+                                {
+                                    "type": "string"
+                                }
+                            ]
+                        },
+                        "flow": {
+                            "type": "string",
+                            "enum": [
+                                "code"
+                            ]
+                        }
+                    },
+                    "required": [
+                        "scheme"
+                    ]
+                }
+            ]
+        }
+    },
+    "type": "object",
+    "properties": {
+        "id": {
+            "type": "string",
+            "format": "uri"
+        },
+        "title": {
+            "$ref": "#/definitions/title"
+        },
+        "titles": {
+            "$ref": "#/definitions/titles"
+        },
+        "properties": {
+            "type": "object",
+            "additionalProperties": {
+                "$ref": "#/definitions/property_element"
+            }
+        },
+        "actions": {
+            "type": "object",
+            "additionalProperties": {
+                "$ref": "#/definitions/action_element"
+            }
+        },
+        "events": {
+            "type": "object",
+            "additionalProperties": {
+                "$ref": "#/definitions/event_element"
+            }
+        },
+        "description": {
+            "$ref": "#/definitions/description"
+        },
+        "descriptions": {
+            "$ref": "#/definitions/descriptions"
+        },
+        "version": {
+            "type": "object",
+            "properties": {
+                "instance": {
+                    "type": "string"
+                }
+            },
+            "required": [
+                "instance"
+            ]
+        },
+        "links": {
+            "type": "array",
+            "items": {
+                "$ref": "#/definitions/link_element"
+            }
+        },
+        "forms": {
+            "type": "array",
+            "minItems": 1,
+            "items": {
+                "$ref": "#/definitions/form_element_root"
+            }
+        },
+        "base": {
+            "$ref": "#/definitions/anyUri"
+        },
+        "securityDefinitions": {
+            "type": "object",
+            "minProperties": 1,
+            "additionalProperties": {
+                "$ref": "#/definitions/securityScheme"
+            }
+        },
+        "support": {
+            "$ref": "#/definitions/anyUri"
+        },
+        "created": {
+            "type": "string",
+            "format": "date-time"
+        },
+        "modified": {
+            "type": "string",
+            "format": "date-time"
+        },
+        "security": {
+            "oneOf": [{
+                    "type": "string"
+                },
+                {
+                    "type": "array",
+                    "minItems": 1,
+                    "items": {
+                        "type": "string"
+                    }
+                }
+            ]
+        },
+        "@type": {
+            "$ref": "#/definitions/type_declaration"
+        },
+        "@context": {
+            "$ref": "#/definitions/thing-context"
+        }
+    },
+    "required": [
+        "title",
+        "security",
+        "securityDefinitions",
+        "@context"
+    ],
+    "additionalProperties": true
+}
\ No newline at end of file