Requests are the reusable building blocks you can arrange to create test sequences, or suites. Each request represents an HTTP request with these elements:

A request suite is a YAML file containing one or more named requests. Here’s an example from movie-queries.ply.yaml in the ply-demo project:

  url: '${baseUrl}/movies?year=${year}&rating=${rating}'
  method: GET
    Accept: application/json

This defines a GET request against ply-movies, an example API we use to illustrate Ply testing. Our request’s name, moviesByYearAndRating, is the top-level key. Note our use of JavaScript template literal expressions embedded in url. Every element of a request can be parameterized using Values.

The next request in this suite illustrates another important feature of expressions:

  # id comes from previous response body
  url:  '${baseUrl}/movies/${@moviesByYearAndRating.response.body.movies[0].id}'
  method: GET
    Accept: application/json

Here we use special designator @ in our URL expression to reference a runtime value from the body of the previous response. This enables us to chain requests, embedding values from previous requests/responses in subsequent requests.

Before we move on to show how you can run your Ply request suites, a few points to keep in mind:


Requests can be run via Ply CLI, or within Visual Studio Code by installing the Ply Extension.

For now let’s use the CLI to run ply-demo’s movie-queries.ply.yaml request suite. First, if you haven’t already, install Ply. Then clone ply-demo and run the request suite:

git clone
cd ply-demo
npm install
ply test/requests/movie-queries.ply.yaml

The output indicates that all tests have passed:

Request 'moviesByYearAndRating' submitted at 8/29/2020, 18:26:54:981
Test 'moviesByYearAndRating' PASSED in 51 ms
Request 'movieById' submitted at 8/29/2020, 18:26:55:031
Test 'movieById' PASSED in 8 ms
Request 'moviesQuery' submitted at 8/29/2020, 18:26:55:039
Test 'moviesQuery' PASSED in 8 ms

Overall Results: {"Passed":3,"Failed":0,"Errored":0,"Pending":0,"Submitted":0}
Overall Time: 305 ms

To understand what it means for a request to have PASSED, continue on to Results.

Note: Like many of these exercises, movie-queries.ply.yaml uses the ply-movies sample API.

Run a single request

Passing a file name to ply executes all requests in sequence. You can also run an individual request by itself:

ply test/requests/movie-queries.ply.yaml#moviesByYearAndRating

Run without verifying

You can tell Ply to submit ad hoc requests without verifying results (see CLI commands):

ply -s test/requests/movie-queries.ply.yaml


In request YAML, body elements may contain any text content. For REST APIs like ply-movies, this is typically JSON. But GraphQL syntax is also supported, as in the following example which queries the GitHub GraphQL API for ply-demo repository topics:

  url: ''
  method: POST
    Authorization: Bearer ${githubToken}
    Content-Type: application/json
    User-Agent: ${github.organization}
  body: |-
    query {
      repository(owner: "${github.organization}", name: "${github.repository}") {
        repositoryTopics(first: 10) {
          edges {
            node {
              topic {

Run this in ply-demo with --verbose to see how Ply translates GraphQL to a JSON request body:

ply --verbose test/requests/github-api.ply.yaml#repositoryTopicsQuery

You’ll receive an HTTP 401 (Unauthorized) response unless you include the githubToken property somewhere in your values. Follow the GitHub token guide to obtain your personal access token. This is a good candidate for your PLY_VALUES environment variable, since you don’t want to share your access token in version control.

Next Topic: Results