API Builder Project


An API Builder application is a standard Node.js application that runs in a runtime environment. This guide covers how to manage your project.

Project structure

A project is made up of several components. To simplify development, API Builder primarily uses a strict directory structure and naming convention to organize the application rather than configuration files.

The following is a list of directories and files that can be found in a project:

File/Folder Name Description
apis Contains API JavaScript files, used to create custom entry points for the application. For details, see API Builder APIs.
app.js The entry point to the application if it is used as a server. You can monitor the startup and shutdown sequence.
blocks Contains Block JavaScript files, used to create pre- and post-processing filters. For details, see API Builder Blocks.


Contains Codeblock, JSON, and Javascript files, used for defining custom functions for use in Flows. Note: The project folder structure will not initially include this folder. You can create the folder and place files in the folder. The files will be loaded on project start.
conf Contains configuration files in JSON format for the project and required connectors. For details, see Project Configuration.
Dockerfile Docker configuration file. For additional information, refer to Dockerize an API Builder Service.


Contains Endpoint JSON files, these are OpenAPI 2.0 (Swagger) documents used to create custom entry points for the application, with execution logic defined by linked Flows


Contains Flow JSON files, used for defining business logic for Endpoints.
models Contains Model JavaScript files, used to define the schema for your data. For details, see Models.
node_modules Contains project dependencies. API Builder automatically installs any project dependencies declared in the package.json file.
package.json NPM configuration file to declare project dependencies and other build or runtime configurations.
package-lock.json NPM configuration file that is generated when NPM modifies either the node_modules tree, or the package.json file. It describes the exact tree that was generated so that subsequent installs are able to generate identical trees, regardless of intermediate dependency updates. The npm shrinkwrap command repurposes the package-lock.json file into a publishable npm-shrinkwrap.json file. For additional information on shrink wrapping a service, refer to npm shrinkwrap. To Dockerize your service, refer to Dockerize an API Builder Service.
Readme.md Provides useful installation and configuration information.
schemas Contains the schemas used within Flows.
swagger May contain Swagger files.
tests Contains the tests used to test the validity of Flows.
web Contains Web files, used to create endpoints that render UI.
web/public Contains static assets, such as CSS, HTML, image, or JavaScript files, for your Web interface.

Initializer file

The app.js file contains code that initializes the server instance. You can hook into the lifecycle events of the server as well as make additional setup or middleware calls to the server or Express app instance.

var APIBuilder = require('@axway/api-builder-runtime'),
    server = new APIBuilder();
// lifecycle examples
server.on('starting', function () {
    server.logger.debug('server is starting!');
server.on('started', function () {
    server.logger.debug('server started!');
// start the server

Node.js version

To specify a Node.js version or a range of Node.js versions, in the package.json file, set the engines.node key to the Node.js version or range of versions. The default Node.js version is 8.9.

"engines": {
    "node": ">= 8.9"

Declare dependencies

The application can import any third-party modules that are supported by standard Node.js applications. Before building a container for your application, make sure all dependencies are listed in the dependencies field in the application's package.json file.

    "dependencies": {

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