uaiMockServer – Create a Mock Rest Server with a single command line

Hello how are you?

Have you ever needed to invoke a REST service, but this service was not created yet?

Imagine that you are developing an APP that needs to invoke an inexistent REST service. You will need to create a fake code that will be replaced once that the real code is finished. No matter if you are working with Java, .NET, PHP, Ruby, Python, etc. You will always need to create a fake invocation method if the REST service is not ready yet.

When we are programming in our unitary test we face the same problem. We will need to create a Mock code that will be invoked during the tests. The problem with this approach is that the real code is never invoked.

How can we solve this problem? Is there a solution that works for delphi, .NET, PHP, Java, Android, IOS, WindowsPhone, etc?

I present to you now my most recent creation: “uaiMockServer”.

With uaiMockServer you will be create a mock server using only a JAR file and a config file. With this server you will be able to execute real HTTP requests, but using your test data.

There are two ways of using uaiMockServer: Standalone and Unit Tests


To use the uaiMockServer as a Standalone server you will manually type the command that starts it. Run the command in a prompt:

java -jar uaiMockServer-{VERSION}.Standalone.jar

You will only need the config file, that we will talk about very soon.

In the sample config file there is a mapping using the port 1234. If you are using linux, type the command:

curl localhost:1234/uaiMockServer/

The HTTP Response will contain a JSON.

Unit Test

First step is to add the project in your pom:


Now you can create a test code like:

public class YourTest {
    private static UaiMockServer uaiMockServer;
    public static void beforeClass() {
        uaiMockServer = UaiMockServer.start();
    public static void afterClass() {
    public void aTest() {
        final Customer customer = // invoke the URL
        assertTrue(customer != null);

You will be able to invoke the URL using any kind of framework. Below you will see a code sample using the RestEasy framework doing a request mapped in the sample config file (that we will see soon):

public void isGetRootReturning200() {
    final String url = "http://localhost:1234/uaiMockServer/";
    Client client = ClientBuilder.newClient();
    Response response =;
    assertEquals(200, response.getStatus());

What is the gain in the test? You will not need a mock code anymore. You can fire a HTTP request from your JUnit test.


To run the project you will need a config file. A simple sample would be like below:

com.uaihebert.uaimockserver {
    port = 1234
    host = localhost
    fileLog = false
    consoleLog = true
    context = /uaiMockServer
    defaultContentTypeResponse = "text/html;charset=UTF-8"
    routes = [
            request {
                path = "/"
                method = "GET"
            response {
                contentType = "application/json;charset=UTF-8"
                statusCode = 200
                body = """{"mockBody":{"title":"Hello World"}}"""

The file must have the .config extension and is not in the JSON format, but has a superset format of the JSON – HCON – used in configurations files (click here for more details).

With this file you can set up the port that will be invoked, the host, header, queryParm and other several options that are described in the uaiMockServer documentation.

Notice that in the configuration was created a request and a response; with these configurations you can mock every request that you want.

If you are going to use the Standalone version the config file must be in the same directory of the JAR file. You can set a different path with the command:

java -jar uaiMockServer-{VERSION}.Standalone.jar FULL_FILE_PATH

If you will run the project in your Unit Tests (like JUnit) you must put the config file in the “src/test/resources” maven folder. Or you can pass the full path like:

uaiMockServer = UaiMockServer.start(FULL_FILE_PATH);

It is free?

Yes, it is. Use it at your will.

Is open source? Yes:

Where is the documentation?

Where can I find the Standalone and the sample Config file:

It has any automated test? Yes, we have a lot of tests and we got 100% code coverage.

What about performance?

In the GIT there is a test that executes 300 requests in less than 2s.

Thanks to:

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