diff --git a/src/jsonschema.js b/src/jsonschema.js
index f6e3ab0..b5e70a6 100644
--- a/src/jsonschema.js
+++ b/src/jsonschema.js
@@ -32,12 +32,14 @@ class JsonSchemaValidator {
 			errors: true
 		}));
 
+		this.collections = null;
+		this.epsgCodes = null;
 		this.fileFormats = {
 			input: null,
 			output: null
 		};
-		this.epsgCodes = null;
 		this.processRegistry = null;
+		this.udfRuntimes = null;
 	}
 
 	getFunctionName(subtype) {
@@ -116,6 +118,28 @@ class JsonSchemaValidator {
 		}
 	}
 
+	setUdfRuntimes(udfRuntimes) {
+		if (!Utils.isObject(udfRuntimes)) {
+			return;
+		}
+		this.udfRuntimes = udfRuntimes;
+	}
+
+	setCollections(collections) {
+		if (!Array.isArray(collections)) {
+			return;
+		}
+		this.collections = [];
+		for(let c of collections) {
+			if (Utils.isObject(c) && typeof c.id === 'string') {
+				this.collections.push(c.id);
+			}
+			else if (typeof c === 'string') {
+				this.collections.push(c);
+			}
+		}
+	}
+
 	// Expects API compatible file formats (see GET /file_formats).
 	setFileFormats(fileFormats) {
 		if (!Utils.isObject(fileFormats)) {
@@ -138,6 +162,24 @@ class JsonSchemaValidator {
 		}
 	}
 
+	async validateCollectionId(data) {
+		if (Array.isArray(this.collections) && !this.collections.find(c => c === data)) {
+			throw new Ajv.ValidationError([{
+				message: "Collection with id '" + data + "' doesn't exist."
+			}]);
+		}
+		return true;
+	}
+
+	async validateUdfRuntime(data) {
+		if (Utils.isObject(this.udfRuntimes) && !(data in this.udfRuntimes)) {
+			throw new Ajv.ValidationError([{
+				message: "UDF runtime '" + data + "' is not supported."
+			}]);
+		}
+		return true;
+	}
+
 	async validateEpsgCode(data) {
 		if (Array.isArray(this.epsgCodes)) {
 			if (this.epsgCodes.includes(data)) {
diff --git a/tests/jsonschema.test.js b/tests/jsonschema.test.js
index 6d4b447..ca6bd52 100644
--- a/tests/jsonschema.test.js
+++ b/tests/jsonschema.test.js
@@ -207,6 +207,75 @@ describe('JSON Schema Validator Tests', () => {
 		await expectError(v, "", inputFormatSchema);
 	});
 
+	var collectionSchema = {
+		"type": "string",
+		"subtype": "collection-id"
+	};
+	test('collection-id', async () => {
+		// No collections set => succeed always
+		await expectSuccess(v, "S1", collectionSchema);
+		// Invalid collections set => succeed always
+		v.setCollections("invalid");
+		await expectSuccess(v, "S1", collectionSchema);
+		// Proper usage...
+		v.setCollections(["S2", "S1"]);
+		await expectSuccess(v, "S2", collectionSchema);
+		await expectSuccess(v, "S1", collectionSchema);
+		await expectError(v, "S3", collectionSchema);
+		v.setCollections([{id: "S2"}, {id: "S1"}]);
+		await expectSuccess(v, "S2", collectionSchema);
+		await expectSuccess(v, "S1", collectionSchema);
+		await expectError(v, "S3", collectionSchema);
+	});
+
+	var runtimeSchema = {
+		"type": "string",
+		"subtype": "udf-runtime"
+	};
+	var udfRuntimes = {
+		"R": {
+			"title": "R v3.x for Statistical Computing",
+			"description": "R programming language with `Rcpp` and `rmarkdown` extensions installed.",
+			"type": "language",
+			"default": "3.5.2",
+			"versions": {
+				"3.1.0": {
+					"libraries": {
+						"Rcpp": {
+							"version": "1.0.10",
+							"links": [
+								{
+									"href": "https://cran.r-project.org/web/packages/Rcpp/index.html",
+									"rel": "about"
+								}
+							]
+						},
+						"rmarkdown": {
+							"version": "1.7.0",
+							"links": [
+								{
+									"href": "https://cran.r-project.org/web/packages/rmarkdown/index.html",
+									"rel": "about"
+								}
+							]
+						}
+					}
+				}
+			}
+		}
+	};
+	test('udf-runtime', async () => {
+		// No collections set => succeed always
+		await expectSuccess(v, "R", runtimeSchema);
+		// Invalid collections set => succeed always
+		v.setUdfRuntimes("invalid");
+		await expectSuccess(v, "R", runtimeSchema);
+		// Proper usage...
+		v.setUdfRuntimes(udfRuntimes);
+		await expectSuccess(v, "R", runtimeSchema);
+		await expectError(v, "Python", runtimeSchema);
+	});
+
 	var wkt2Value = 'GEOGCRS["WGS 84",DATUM["World Geodetic System 1984",ELLIPSOID["WGS 84",6378137,298.257223563,LENGTHUNIT["metre",1]]],PRIMEM["Greenwich",0,ANGLEUNIT["degree",0.0174532925199433]],CS[ellipsoidal,2],AXIS["geodetic latitude (Lat)",north,ORDER[1],ANGLEUNIT["degree",0.0174532925199433]],AXIS["geodetic longitude (Lon)",east,ORDER[2],ANGLEUNIT["degree",0.0174532925199433]],ID["EPSG",4326]]';
 	var wkt1Value = 'GEOGCS["WGS 84",DATUM["WGS_1984",SPHEROID["WGS 84",6378137,298.257223563,AUTHORITY["EPSG","7030"]],AUTHORITY["EPSG","6326"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AXIS["Latitude",NORTH],AXIS["Longitude",EAST],AUTHORITY["EPSG","4326"]]';
 	var projValue = "+proj=moll +lon_0=0 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +units=m +no_defs";