I'm trying to create an api route with input parameters but I'm not getting the expected result.

Here is my webapi.xml:

<?xml version="1.0"?>
<routes xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../../../../../app/code/Magento/Webapi/etc/webapi.xsd">
    <route url="/V1/foo" method="POST" secure="true">
        <service class="..\FooInterface"
                 method="getFooById"/>
        <resources>
            <resource ref="anonymous"/>
        </resources>
        <data>
            <parameter name="id" force="true">%id%</parameter>
        </data>
    </route>
</routes>

Here my interface:

interface FooInterface
{
    /**
     * Test function
     *
     * @api
     * @param string $id
     * @return string
     */
    public function getFooById($id);
}

And here the class:

class Foo implements FooInterface
{
    /**
     * {@inheritdoc}
     */
    public function getFooById($id){
        return $id;
    }
}

I'm omitting the di.xml with the preference. Now if I call that route whatever I do all I get back is %id%. Even if I don't put any parameter I get that instead of an error or something.

What am I doing wrong here?

Here is the call in postman:

I tried:

• sending a get request
• sending a get request with parameter /order?id=foo
• sending a post request
• sending a post request with form-data
• sending a post request with raw data (as seen in screenshot)

All have the same result -> %id%