diff --git a/.gitignore b/.gitignore
index ded541e..aec56e9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,3 +15,4 @@ create-schematic-gen-site-test-*
 *.obj
 *.lst
 *.jar
+extracts/
\ No newline at end of file
diff --git a/dub.json b/dub.json
index ce30453..469ea33 100644
--- a/dub.json
+++ b/dub.json
@@ -4,7 +4,7 @@
 	],
 	"copyright": "Copyright © 2023, Andrew Lalis",
 	"dependencies": {
-		"handy-httpd": "~>7.6.1",
+		"handy-httpd": "~>7.6.3",
 		"slf4d": "~>2.4.1"
 	},
 	"description": "HTTP server for generating schematic materials lists.",
diff --git a/dub.selections.json b/dub.selections.json
index cda082b..d350906 100644
--- a/dub.selections.json
+++ b/dub.selections.json
@@ -1,7 +1,7 @@
 {
 	"fileVersion": 1,
 	"versions": {
-		"handy-httpd": "7.6.1",
+		"handy-httpd": "7.6.3",
 		"httparsed": "1.2.1",
 		"slf4d": "2.4.1",
 		"streams": "3.5.0"
diff --git a/site/files.js b/site/files.js
index 3139f49..13a018d 100644
--- a/site/files.js
+++ b/site/files.js
@@ -1,6 +1,8 @@
 const form = document.getElementById("schematic-form");
+const resultContainer = document.getElementById("result-container");
 form.onsubmit = async (e) => {
     e.preventDefault();
+    resultContainer.innerHTML = "";
     console.log(e);
     const data = new FormData(form);
     console.log(data);
@@ -10,9 +12,12 @@ form.onsubmit = async (e) => {
             body: data
         });
         const result = await response.json();
-        console.log("Success:", result);
+        const extractId = result.extractId;
+        const url = window.location.origin + "/extracts/" + extractId;
+        resultContainer.innerHTML = `<p>Copy this URL, and provide it to the computer: <em>${url}</em></p>`;
         form.reset();
     } catch (error) {
         console.error("Error: " + error);
+        resultContainer.innerHTML = `<p>An error occurred: ${error}</p>`;
     }
 };
\ No newline at end of file
diff --git a/site/index.html b/site/index.html
index 5cc0148..d287d61 100644
--- a/site/index.html
+++ b/site/index.html
@@ -14,6 +14,9 @@
         <input id="schematic-file-input" name="schematics" type="file" multiple accept=".nbt" required/>
         <button type="submit">Submit</button>
     </form>
+    <div id="result-container">
+
+    </div>
     <script src="files.js"></script>
 </body>
 
diff --git a/source/app.d b/source/app.d
index c46acbf..84af2fc 100644
--- a/source/app.d
+++ b/source/app.d
@@ -3,6 +3,12 @@ import handy_httpd.handlers.path_delegating_handler;
 import handy_httpd.handlers.file_resolving_handler;
 import slf4d;
 import slf4d.default_provider;
+import std.path;
+import std.file;
+
+const EXTRACTS_DIR = "extracts";
+const EXTRACT_FILENAME = "__EXTRACT__.json";
+const EXTRACT_COMMAND = ["java", "-jar", "materials-extractor-v1.0.0.jar"];
 
 void main() {
 	auto provider = new shared DefaultProvider(true, Levels.INFO);
@@ -15,7 +21,7 @@ void main() {
 
 	PathDelegatingHandler handler = new PathDelegatingHandler();
 	handler.addMapping("POST", "/extracts", &handleExtract);
-	handler.addMapping("GET", "/extracts/{extractId:uint}", &getExtract);
+	handler.addMapping("GET", "/extracts/{extractId}", &getExtract);
 
 	FileResolvingHandler fileHandler = new FileResolvingHandler("site", DirectoryResolutionStrategies.serveIndexFiles);
 	handler.addMapping("/**", fileHandler);
@@ -23,15 +29,46 @@ void main() {
 }
 
 void handleExtract(ref HttpRequestContext ctx) {
-	MultipartFormData data = ctx.request.readBodyAsMultipartFormData();
-	infoF!"Read %d files: "(data.elements.length);
-
 	import std.json;
-	JSONValue result = JSONValue.emptyObject;
-	result.object["extractId"] = JSONValue(42);
-	ctx.response.writeBodyString(result.toJSON(), "application/json");
+	import std.uuid;
+	import std.process;
+	import std.stdio;
+
+	immutable UUID extractId = randomUUID();
+	MultipartFormData data = ctx.request.readBodyAsMultipartFormData();
+	// TODO: Validate data (unique filenames, no non-file elements, etc.)
+	const extractDir = buildPath(EXTRACTS_DIR, extractId.toString());
+	if (!exists(extractDir)) {
+		mkdirRecurse(extractDir);
+	}
+	string[] filenames;
+	foreach (MultipartElement element; data.elements) {
+		if (element.filename.isNull) continue;
+		const filePath = buildPath(extractDir, element.filename.get());
+		std.file.write(filePath, element.content);
+		filenames ~= filePath;
+	}
+	const extractJsonPath = buildPath(extractDir, EXTRACT_FILENAME);
+	infoF!"Running extract process on files: %s"(filenames);
+	Pid pid = spawnProcess(EXTRACT_COMMAND ~ filenames, std.stdio.stdin, File(extractJsonPath, "w"));
+	int exitCode = wait(pid);
+	infoF!"Exit code: %d"(exitCode);
+	if (exitCode != 0) {
+		ctx.response.setStatus(HttpStatus.INTERNAL_SERVER_ERROR);
+		ctx.response.writeBodyString(readText(extractJsonPath));
+	} else {
+		JSONValue result = JSONValue.emptyObject;
+		result.object["extractId"] = JSONValue(extractId.toString());
+		ctx.response.writeBodyString(result.toJSON(), "application/json");
+		// Remove schematic files after we are done.
+		foreach (string schematicFile; filenames) {
+			std.file.remove(schematicFile);
+		}
+	}
 }
 
 void getExtract(ref HttpRequestContext ctx) {
-	infoF!"Getting extract: %d"(ctx.request.getPathParamAs!uint("extractId"));
+	string extractId = ctx.request.getPathParamAs!string("extractId");
+	const extractFile = buildPath(EXTRACTS_DIR, extractId, EXTRACT_FILENAME);
+	fileResponse(ctx.response, extractFile, "application/json");
 }