TALKING TO

25% OF THE WEB

An in-depth report and analysis ​

on the WordPress REST API
TALKING TO 25% OF THE WEB / HUMAN MADE LTD. 01

Contents

03 05
Executive Summary The Headless CMS

10 18 23
What is a REST API? What is the Why Use the
WordPress REST API? WordPress REST API?

30 33 40
How the WordPress Challenges Presented Resources
REST API Will Change by the REST API
WordPress Development
TALKING TO 25% OF THE WEB / ABOUT THE AUTHORS 02

About the Authors

Tom Willmot is the co-founder and CEO of Joe Hoyle is the co-founder and CTO of Human
Human Made. He has over 10 years experience Made, where he leads the development team
bringing open source technology to enterprise. and the overall technical direction of the
He lives in the UK with his wife and daughter. company. He is a member of the WordPress REST
API development team

Contributors Ryan McCue - WordPress REST API Team Co-Lead

Daniel Bachhuber - WordPress REST API Team

Siobhan McKeown - Writer & Editor

Michael Pick - Designer

TALKING TO 25% OF THE WEB / EXECUTIVE SUMMARY 03

Executive Summary

WordPress is an open-source content management

system which is used to power millions of websites and
blogs, and an increasing number of web applications.

It currently powers more than 25% of the top 10 million websites

on the Internet. WordPress’ usability, extensibility, and mature
development community make it a popular choice for web
projects of all sizes.

WordPress, like many other CMSes, is monolithic. It

provides everything you need to run a website, and can be
extended further with third-party plugins and themes. But
on today’s web, we are moving beyond the monolithic CMS.
WordPress, along with others, is leading the charge to a
future where the CMS acts as a central hub, consuming and
aggregating content and data from other tools and services
and in-turn exposing its own content and data via APIs.
TALKING TO 25% OF THE WEB / EXECUTIVE SUMMARY 04

The WordPress REST API is a huge step towards this

future. Exposing WordPress content and data as JSON The potential
via a standardised RESTful API unlocks your data and implications for
will enable an explosion in the number and complexity of your business
integrations.
are far-reaching,
particularly for large
By embracing the WordPress REST API, you can more
easily: custom builds and
• separate your frontend delivery from the CMS applications.
• power multiple frontends from the same content (think
a website, app, Apple News, etc.)
• and use WordPress as part of complex multi-service
workflows (like pushing content to a separate service
for translation before pulling those translations back into
WordPress).

The potential implications for your business are far-reaching,

particularly for large custom builds and applications.
WordPress provides content management and content
capture, while making the data available to other frontend
technologies. This permits engineering teams to work
independently on discrete parts of a larger project, and
allows for more stable third-party integrations.

With the REST API, WordPress stops being a web

development tool used in isolation. It is one module that is
available in a web developer’s toolkit; a building block to be
used in many kinds of applications.
TALKING TO 25% OF THE WEB / THE HEADLESS CMS 05

The Headless CMS

We look at the difference between a

traditional and a headless CMS, how a
headless CMS slots into web development,
and discuss some of the advantages of using
a headless CMS for your web project.
TALKING TO 25% OF THE WEB / THE HEADLESS CMS 06

A headless CMS is used only for data capture, storage, and delivery, making it frontend
agnostic. Its data can be displayed using any frontend technology, whether in a browser,
mobile application, syndication, or elsewhere.

Monolothic CMS vs Headless CMS

Frontend Frontend

Data retrieved by JS or
other language
PHP controls
PHP renders
the data

the data

Database Database

A traditional CMS deals with data A headless CMS decouples the theme
collection, delivery, and display. system, allowing you to replace it with
WordPress, for example, has a backend the frontend technologies of your choice.
where users can enter data. This data is What’s left is the data storage method and
stored in a MySQL database, retrieved web application for authors and editors,
from the database using PHP, and then while the data is delivered to the frontend
displayed in the browser using the using an API.
theme system.
TALKING TO 25% OF THE WEB / THE HEADLESS CMS 07

Decoupling content management from

Fast, in-browser
frontend display
experiences, in
By decoupling content management from frontend display,
real-time, without
a headless CMS allows developers to use any technology
to display content. Developers are not locked into the having to wait for
templating engine provided by the CMS. The CMS might
PHP queries.
be written in PHP, but developers working in languages
like JavaScript, Java, Ruby, and Swift can use an API to
retrieve, store and display data. A frontend developer has
complete control over the website or application’s markup
and user experience, using client-side technologies to
create smooth interactive experiences. It also means that
if the frontend needs to be displayed in a new way (for
example a redesign or to display content on a new device)
the CMS can still store the data, removing the
need for complex migrations.

Fast, interactive experiences

When you use a headless CMS there are two components: the
CMS itself and the frontend display. The CMS focuses only on
content management, without having to assemble formatted
responses, while the client-side technology can quickly display
that data in the browser. Using client-side technologies for
display means that in-browser experiences are fast, acting in
real-time, without having to wait for PHP queries to retrieve
information from the database. There is a significant increase
in performance when using JavaScript vs PHP: Node.js, for
example, can handle many more requests than PHP due to
its asynchronous event-driven nature. This can be especially
useful when an application requires many connections open
simultaneously.
TALKING TO 25% OF THE WEB / THE HEADLESS CMS 08

CMS

REST API

One content management system,

multiple frontends

With a traditional, monolithic CMS, data is simply displayed

by the CMS itself. Data stored in a headless CMS is
available for display in any context. You may want to use it
for a website now, but later you may decide to use the same
data for a desktop or touch screen application. The stored
data is always available via the API.
TALKING TO 25% OF THE WEB / THE HEADLESS CMS 09

Multi-service content pipelines

A headless CMS can be used to store all of the data for one
site or application, or it can just be one element of a larger
application that retrieves and aggregates data. This means
that data can be integrated into existing workflows as just
one layer. For example, it could be used just as a layer for
translating content which is then pushed to another CMS.

Print CMS
Original articles authored here

Pushed to WordPress via REST API

WordPress
Articles are translated using custom
workflow in wp-admin

App Backend Translated Website Backend

CMS for mobile apps articles pushed CMS for website
on to multiple
delivery CMS’s

Android App iOS App Blackberry App Website RSS Feed Apple News
TALKING TO 25% OF THE WEB / WHAT IS A REST API? 10

What is a REST API?

We look at what the REST architectural style

is, explore the elements that make an API
RESTful, and consider some of the ways in
which open APIs are changing the internet.
TALKING TO 25% OF THE WEB / WHAT IS A REST API? 11

What is REST?

Representational State Transfer (REST) is a software

architectural style for Application Programming Interfaces
(APIs) that consists of guidelines and best practices for
creating scalable web services. REST uses simple HTTP
to make calls between machines.

This happens via a request/response mechanism between

the server and the client. For example, a client, let’s say an
Android application, makes a request for the most recent
posts from the website. The server knows how to interpret
this request, through REST, and satisfies the response by
providing the most recent posts in a format understood by
the client.

REST requests interact with the resources in your

application (e.g. a Post or Page). These interactions
are typically Reading, Creating, Updating, or Deleting.
Combined with HTTP, REST requests are formed using
four verbs:

• POST: Create a resource

• GET: Retrieve a resource
• PUT: Update a resource
• DELETE: Delete a resource

The data retrieved is supplied in a machine-readable format,

often JSON in modern web applications.
TALKING TO 25% OF THE WEB / WHAT IS A REST API? 12

What makes an API RESTful?

REST was
An API must have the following architectural features proposed by Roy
to be considered RESTful:
Fielding in his
• Client-server: the client is separated from the 2000 dissertation
server. This means that clients are not concerned
with data storage and servers are not concerned Architectural
with display. This ensures that data is portable Styles and the
and can be reused in multiple clients, and servers
are simpler and more scalable. Design of Network-
• Cacheable: clients can, and should, cache based Software
responses to improve performance, and avoid
the server with every request. Architectures.
• Stateless: the necessary state to handle the request is
contained in the request itself, whether as part of the
query parameters, URL, body, or headers.
• Uniform interface: information transferred via REST
comes in a standardised form, creating a simplified,
decoupled architecture.
• Layered System: the architecture is composed of
hierarchical layers. Each component cannot “see”
beyond its layer: a client cannot tell if it’s connected to
the server or to an intermediary.

A separate, but closely-related concept is hypermedia.

Hypermedia allows a client to more fully discover a REST
API without needing to know anything about the structure
of the API. It’s similar to hyperlinks on the human-readable
web (which enable discovering new sites and content).
The server provides the information the client needs to
interact with it. This means that the client can interact with
the server in complex ways without knowing anything
beforehand about it.
TALKING TO 25% OF THE WEB / WHAT IS A REST API? 13

Source: Programmable Web

What is an open API?

Open APIs are publicly available APIs that give developers

access to proprietary software information that they can
make use of in their own software and applications. REST is
the ideal architecture for creating an Open API for the web
because, by using HTTP, it is built on the principles of the
open web. To leverage an open REST API a developer just
needs to make a HTTP request.
TALKING TO 25% OF THE WEB / WHAT IS A REST API? 14

By making data available for developers to use in

their own applications, open APIs are transforming The impact of
the internet. Developers can access data across APIs cannot be
services, creating applications that aggregate
information from different providers. The impact underestimated;
of APIs cannot be underestimated; they are they are
transforming the way businesses and services are
run. For example: transforming the
way businesses and
• Around 25% of annual revenue of the fundraising
platform JustGiving is API-driven services are run.
• In 2011, Twitter reported that they had more than
one million applications registered, with a number
of entire companies built off the API
• Data feeds from the Skyscanner API are used by
startups like Hitlist, Go Euro, and Pintrips
• Hilton is making use of Uber’s API to allow guests
to book rides from the Hilton Honors App

This aggregation of public data across different

platforms enables the creation of feature-rich,
powerful applications that do more than any
individual product or service could do on its own.
TALKING TO 25% OF THE WEB / CASE STUDY: NOMADBASE 15

Case Study: Nomadbase

Nomadbase is a service that facilitates

remote working and the digital nomad way of
life. Using public APIs, it aggregates data from
social networking services to create a map of
nomad locations across the world.
TALKING TO 25% OF THE WEB / CASE STUDY: NOMADBASE 16

“ Our development
team has a lot of
experience with
WordPress, and
recognises its
ability to provide a
solid foundation to
build an application
on. Leveraging its
users system for
signups, the REST
API for all external
communication, and extremely common server requirements, we
were able to get the prototype up and running in a matter of days,
rather than weeks or months.

We used the REST API for not only the communication with the
frontend application, but also inbound data coming from Facebook
and Foursquare to collect user location data.
Joe Hoyle, Nomadbase
TALKING TO 25% OF THE WEB / CASE STUDY: NOMADBASE 17

Why use WordPress and the REST API?

WordPress enabled
WordPress enabled the developers to get the first the developers to
version of Nomadbase up and running quickly, get the first version
providing both a stable central platform where data
of Nomadbase up
can be aggregated and an API for delivering the data
and running quickly.
to the frontend.

The build

Nomadbase uses APIs to gather geodata from Facebook,

Swarm, Twitter, Instagram, and TripIt. This data is stored in
custom tables in the MySQL database. Data is then sent over
the WordPress REST API to a React frontend and displayed in
the browser. Leaflet is used to create overlays on the map.

When a new user signs up for Nomadbase, data is requested

from five different social networks. This leads to significant
background processing. To speed this up, wp-cron is replaced
by a system tool called Cavalcade, developed by Human
Made for large-scale WordPress installations

The next step for Nomadbase is a React Native iOS

application that reuses code from the browser app. As all the
data and user actions that exist for Nomadbase are processed
by the REST API, no additional backend work needs to be
done to build the new application.
TALKING TO 25% OF THE WEB / WHAT IS THE WORDPRESS REST API? 18

What is the
WordPress REST API?

We look at the specifics of the WordPress

REST API, including its infrastructure and
endpoints, its authentication methods and the
concept of hypermedia. We also introduce
you to the team behind it.
TALKING TO 25% OF THE WEB / WHAT IS THE WORDPRESS REST API? 19

HTTP request

WordPress API Infrastructure API Endpoints

wp-settings.php

Authentication

WP_REST_Request
Rewrite Handler REST API bootstrap Parameter Sanitization Callbacks

WP_REST_Server::dispatch Parameter Validation Callbacks

WP_REST_Response
Endpoint Callback
WP_REST_Server::serve_request

WP_REST_Response

JSON-ready data WP_REST_Server::response_to_data

HTTP response

The WordPress REST API allows access to a website’s

data, including users, posts, and taxonomies. In the past,
developers needed to use WordPress’ built-in theme system
and administration panel to display and edit content on
a site.

The REST API decouples the WordPress backend from the

frontend, allowing developers to use it as an application
platform: WordPress is used for data entry and storage, and
the frontend can be built in any programming language.
The REST API transforms WordPress into a headless CMS.
TALKING TO 25% OF THE WEB / WHAT IS THE WORDPRESS REST API? 20

Infrastructure

WordPress 4.4 contains the infrastructure for the WordPress

REST API. This can be thought of as a construction kit
for RESTful APIs in WordPress: it enables developers
to build their own REST APIs, handling things like API
discovery, request routing, arguments, JSON serialisation/
deserialisation, and response codes. If you are building a
website, application, theme or plugin, you can use the API
by adding your own custom endpoints.

The REST API decouples the WordPress backend

from the frontend, transforming it into a
headless CMS.

Endpoints

Endpoints are functions that are available through the API:

they’re the places where developers can do something with
the CMS, whether that’s creating, retrieving, updating or
deleting (CRUD) data. This includes the four core data types
in WordPress (posts, comments, terms, and users) initially,
although these will grow in future versions of WordPress to
support all data on the site.
TALKING TO 25% OF THE WEB / WHAT IS THE WORDPRESS REST API? 21

Authentication
Who should be
A major challenge around building a REST API is allowed to update
authentication: how does an API know that a user should
be allowed to update content on a site, for example?
content on a site
Who should be allowed to retrieve data? Under what or retrieve data,
conditions? The WordPress REST API uses two forms of
authentication:
and under what
conditions?
• Cookie - this is the basic authentication method used in
WordPress. When you log into your dashboard a cookie
is set in your browser. This method is only viable when
the current user is logged into WordPress and that user
has the capability to perform the action requested.
• OAuth - this is the main authentication method used for
external clients, i.e. any third-party site or application
that wants to interact with the API. With OAuth, logged in
users can authorise clients to act on their behalf. Clients
are issued with OAuth tokens so they can interact with
the API. The REST API uses OAuth 1.0a so that it can
be used by all WordPress websites; OAuth 2.0 requires
HTTPS but WordPress does not.

In addition, there is a Basic Authentication method for

external clients. However, this is only recommended for
development environments as it involves passing your
username and password on every request, and giving your
credentials to clients.
TALKING TO 25% OF THE WEB / WHAT IS THE WORDPRESS REST API? 22

Team

The WordPress REST API has contributions from 72 developers. However, the
team has had four core members:

Ryan McCue (Human Made) Rachel Baker (Wirecutter)

Co-Lead of the REST API Co-Lead of the REST API

Joe Hoyle (Human Made) Daniel Bachhuber (Hand Built)

TALKING TO 25% OF THE WEB / WHY USE THE WORDPRESS REST API? 23

Why use the

WordPress REST API?

We explore some of the reasons that you may

want to use a headless WordPress with the
REST API in your own projects, drawing out
specific technical and project management-
related benefits.
TALKING TO 25% OF THE WEB / WHY USE THE WORDPRESS REST API? 24

The WordPress REST API allows you to use WordPress as

a headless CMS. Developers can interact with WordPress The API frees
independently of the theme system, using it only as a data developers and
storage and delivery platform. There are many benefits to
doing this. allows them to use
any technology
Create context-specific solutions that will solve a

Around 25% of all websites use WordPress. These problem in their

websites are PHP-based, with frontends built with the specific context.
WordPress theme system. The API frees developers
and allows them to use any technology that will solve a
problem in their specific context. WordPress no longer has
to be concerned with the frontend: it can just deliver data
to any frontend technology. A developer can take data from
a WordPress website and display it using the technology
of their choice, whether that’s for a website, Android
application, iOS application or whatever context the data is
needed.

Reusable, portable content

The content entered into WordPress is no longer limited to

being displayed on a WordPress website. A REST API-powered
website has content which is infinitely portable. Your content
authors only need to enter data in one place. Once it has been
authored and published in WordPress, it’s now available via the
API and can be delivered to websites, web applications, and
mobile and desktop applications.
TALKING TO 25% OF THE WEB / WHY USE THE WORDPRESS REST API? 25

Separation of concerns
Your JavaScript
In traditional WordPress development, where the developer no longer
frontend and backend are tightly coupled, frontend
developers need to be familiar with at least some needs to learn
aspects of WordPress. This makes it difficult to hire and PHP to work with
work with purely frontend developers. In a decoupled
environment this is no longer a problem. Different WordPress, and
teams can work on different parts of a project while your WordPress
having access to the same data: a backend team can
work on WordPress and the database, a team can build developer no longer
the frontend in JavaScript or another web technology, needs to tinker
you can have an iOS team and an Android team. Your
JavaScript developer no longer needs to learn PHP to with JavaScript.
work with WordPress, and your WordPress developer
no longer needs to tinker with JavaScript. This widens
the pool of development talent available to work on
your website or application, and streamlines project
management.

Familiar backend for authors and publishers

One of the reasons WordPress has been so successful is that

it provides an easy-to-understand interface for non-technical
users. With the REST API, you don’t have to decide between
using your frontend technology of choice and giving your
authors the admin interface they want. Authors and editors can
work in the WordPress admin and the data is delivered to the
frontend by the API. You have the advantage of providing an
admin interface which many authors will already be familiar
with, reducing the need for training and re-training, and letting
authors quickly start adding content.
TALKING TO 25% OF THE WEB / WHY USE THE WORDPRESS REST API? 26

Integrate WordPress as one part of a

All of your services
content-authoring workflow
and data can
WordPress may only be suitable for one aspect of your
be centralised
website or application. The REST API allows you to use
WordPress for just those elements that it is suitable for. while providing
The New York Times, for example, uses WordPress for its
your authors
live coverage platform: data is received via WebSocket
from a custom-built service, rendered in React, and with a familiar,
served to the frontend via the WordPress REST API. In
straightfoward
August 2015, the paper even added Slack to its publishing
workflow. This makes WordPress just one module in a interface.
larger stack, making it more available to the wider web
development community for smaller, specific tasks.

WordPress as a central repository

The web is increasingly API-driven, with websites and

services aggregating data. The REST API makes it possible for
WordPress to be the central place that brings all of this data
together. This means that all of your services and data can be
centralised while providing your authors with a straightforward
interface that they are familiar with. This also provides a
standard platform for further functionality with WordPress’
plugin system.

Develop with live data

When data is exposed through the REST API it can be used by

developers in their development environment. Content can be
added to the CMS and is available to developers whether they
are working on the frontend, the admin, or any applications.
TALKING TO 25% OF THE WEB / CASE STUDY: USTWO 27

Case Study: ustwo

ustwo wanted a decoupled website with a

WordPress backend and a frontend built
with React.
TALKING TO 25% OF THE WEB / CASE STUDY: USTWO 28

“ We chose
WordPress as we
wanted to have an
established open
source CMS so that
we can be confident
that we’ll never be
left without support
or ability to change.

To fulfil our design

ambitions we
decided to build our frontend as a single-page application, which
was made possible with the emerging WP-API.
Daniel Demmel, ustwo
TALKING TO 25% OF THE WEB / CASE STUDY: USTWO 29

ustwo.com architecture = Docker container

S3 image Image React SPA CDN responding

bucket CDN (in browser) to ustwo.com

Media uploads
(responsive)
Content:
client-side
WordPress rendering
WordPress
CMS admin API Proxy
(nginx)

Express and
React code
Content: /share/nginx/
assets/etc/nginx /etc/ustwo/ssl
server-side
rendering

MySQL Memcached
Isomorphic app Assets/Code Vault
(Node.js server) (compiled on CI) (SSL certificates)

ustwo.com frontend
ustwo.com backend

Source: ustwo

On the WordPress side, a custom page

builder plugin gets authors to enter content
The build
in a modular fashion. This ensures that the

The ustwo website is a single-page content is modular and portable to different

application: the frontend is built using React contexts.

and WordPress manages the content. React

was used because it allows for isomorphic The infrastructure for the REST API is used

rendering (pages can be rendered on the along with a bespoke API comprising custom

server or by the client). There is a Node.js endpoints that deliver content in JSON format

server that enables server-side rendering. to the frontend.

TALKING TO 25% OF THE WEB / HOW THE REST API WILL CHANGE WORDPRESS DEVELOPMENT 30

How the REST API will change

WordPress development

We look at some of the ways that the REST

API will change WordPress development
and the impact that this will have both for
WordPress-based websites and applications,
and for the people creating them.
TALKING TO 25% OF THE WEB / HOW THE REST API WILL CHANGE WORDPRESS DEVELOPMENT 31

WordPress as part of a larger stack

WordPress has a familiar and easy to use user interface which

authors want to use for managing and publishing content. With
the REST API, you can provide this interface to your authors
without compromising on the rest of your stack.

Developers will independently focus on different

aspects of the website or application, working
with live data retrieved using the API.

New approaches to project management

The separation of concerns that come with a REST API

project mean approaching project management in a new way.
Developers will independently focus on different aspects of the
website or application, working with live data retrieved using
the API.

The WordPress developer as a

backend specialist

There will be an increase in the number of WordPress

developers who are backend specialists, focusing on the admin
screens and the database, while leaving the frontend layer to
frontend developers.
TALKING TO 25% OF THE WEB / HOW THE REST API WILL CHANGE WORDPRESS DEVELOPMENT 32

Permeation of The emergence

WordPress outside of of funnelled,
PHP communities role-based admins

As a single module in a larger stack, The REST API allows developers

WordPress will be used increasingly to create funnelled administration
outside of its traditional community. experiences that focus on a
The REST API allows developers to particular user doing particular
create websites and applications in actions. These focused admins will
any language without having to roll remove clutter and empower the
their own CMS. user to do exactly what they need
to do.

Focused admins will remove clutter and empower the user to

do exactly what they need to do.

The enhancement of built-in Explorations in

WordPress functionality non-GPL products

The REST API makes it easier The absolute separation of

for developers to enhance concerns means that frontend
functionality in the WordPress products that retrieve data from
admin. Developers can create the API will not need to be GPL.
client-side features in the admin It’s unlikely, however, that we’ll see
that are more advanced and more a vast increase in API-powered
performant than can be achieved themes due to the challenges
with PHP. of rebuilding native WordPress
functionality on the frontend.
TALKING TO 25% OF THE WEB / CHALLENGES PRESENTED BY THE REST API 33

Challenges presented by
the REST API

We explore the challenges that will be

brought about by the REST API and discuss
some of the ways that these challenges will
be addressed both in individual projects and
by the wider WordPress community.
TALKING TO 25% OF THE WEB / CHALLENGES PRESENTED BY THE REST API 34

The introduction of the REST API marks a new era in

WordPress development. Not all the ways that the REST API
will change WordPress are clear, but some challenges are
already emerging.

The REST API will be of most significance to large

custom builds and WordPress-based SaaS products.

Loss of core functionality

A REST API driven website loses frontend features that are

linked to the WordPress theme system, like menu management
and post previews. Frontend developers need to take
responsibility for re-implementing features that come for free
with WordPress. If they are not rebuilt, users must do without
them. When writing project specifications for an API-driven
project, it will become necessary to be very specific about the
features that the client needs and not just assume that because
they are in WordPress they are available.

To solve this problem, we anticipate the emergence of REST

API base themes that rebuild WordPress features on the
frontend. These boilerplate themes will be written in different
languages and will provide a starting point for frontend
developers to build on.
TALKING TO 25% OF THE WEB / CHALLENGES PRESENTED BY THE REST API 35

Disempowers WordPress you may just be using data on

site builders a website, but you may want to
make it available later to a native
In addition to its ease of use, application. The focus here is on
WordPress’ strength is that it is content management as opposed
easy to set up a website. Through to web publishing. This data needs
WordPress, many people gain to be structured in a modular
experience of PHP, CSS, and manner, separate to the CSS and
HTML, gaining confidence to make HTML. For this reason, REST API-
changes to the frontend of their driven sites will not rely on the
website. The REST API completely WYSIWYG capability in TinyMCE
decouples the frontend from the for page layouts, instead using
backend, disempowering those content structured by modular
users, and making the frontend page builders.
only editable by developers.

For this reason, it is unlikely that Data needs to be structured in a

we will see a major disruption to modular manner, separate to the
the WordPress theme market.
Instead, the REST API will be of CSS and HTML.
most significance to large custom
builds and WordPress-based SaaS
products. WordPress’ commitment to
backwards (and forwards)
compatibility ensures that data
The necessity for produced by the API will continue
structured, portable data to be readable and usable well into
the future. This means that you can
A headless WordPress requires safely store it knowing that it will
data that can be used across continue to be available through
multiple contexts. This means a well-supported API. In addition,
creating and storing it in a way the WordPress REST API is open,
that is completely frontend ensuring that your data can be
agnostic. In the first instance, moved out of your site using
standard tools.
TALKING TO 25% OF THE WEB / CHALLENGES PRESENTED BY THE REST API 36

WordPress API Progressive Enhancement

Data passed to Rendered pages

delivered to

WordPress Node JS Browser

REST API

Stores Data Renders Pages Pages enhanced using JS

Dealing with progressive enhancement

One method is to
In an increasingly JavaScript-driven world, progressive render frontend
enhancement is a challenge that has to be addressed. templates on the
Some people have JavaScript disabled in their browser,
either because they use assistance technologies, because
server using
of personal preference, or because the organisation Node.js, and
they work for requires it to be turned off. If content from a enhance the
REST API driven WordPress website is delivered to a JS-
powered frontend, these people will simply see a
website frontend
blank page. using client-side
JavaScript.
Developers need to address these issues to ensure
that the web stays accessible. One method is to render
frontend templates on the server using a technology like Node.
js, and then enhance the website on the frontend using client-
side JavaScript. This setup, however, requires an additional
server, and developers with the experience to implement it.
TALKING TO 25% OF THE WEB / CASE STUDY: NPM 37

Case Study: npm

npm wanted to use the REST API to deliver

custom brochure pages and upsell boxes on
their website.
TALKING TO 25% OF THE WEB / CASE STUDY: NPM 38

“ Security was
of paramount
importance to us
and as a result, we
needed a headless
WP instance hosted
under the same
constraints as in
our production
environment. This
meant reliance on
the WordPress API
to deliver authored content via JSON to our build, giving us the
ability to parse and display CMS-generated content without having
to grant access to any non-whitelisted IP Addresses.
Nick Cawthon, npm
TALKING TO 25% OF THE WEB / CASE STUDY: NPM 39

Why use WordPress and the REST API?

The website
npm wanted to use WordPress as a central repository stays fast without
for their documentation and their product pages. Its having to expend
straightforward interface means that content authors
effort scaling the
can easily add data, which is delivered to the client in
database.
JSON format.

The build

The npm website has a WordPress backend and admin.

A bespoke API built of custom endpoints serves content
in JSON format to a Node.js server. This renders the final
HTML and sends it to the browser where Handlebars
renders the templates. The API doesn’t just send the
data: it sends rendered HTML along with scripts and
stylesheets. This is cached by the Node.js server so that
the website stays up even if WordPress is unavailable. It
also means that the website stays fast without having to
expend effort scaling the database.

Some customisations recreate the post preview feature

of WordPress. Parts of the CSS templates and handlebars
frontend are used to create a basic WordPress theme
which authors use to preview posts before they are
published and pushed to the frontend.
TALKING TO 25% OF THE WEB / RESOURCES 40

Resources
TALKING TO 25% OF THE WEB / RESOURCES 41

Resources

The WordPress REST API

• Official website and documentation (wp-api.org)

• WordPress core discussion about the REST API

(hmn.md/wp-api/core/)

Client Libraries
• Node.js (hmn.md/wp-api/node/)

• Backbone.js (hmn.md/wp-api/backbone/)

• AngularJS (hmn.md/wp-api/angular/)

• PHP Client (hmn.md/wp-api/php-client/)

• C# (hmn.md/wp-api/c/)
TALKING TO 25% OF THE WEB / RESOURCES 42

Resources

Authentication
• OAuth (hmn.md/wp-api/oauth/)

• Basic Authentication (hmn.md/wp-api/basic-auth/)

Tools
• WP-CLI client (hmn.md/wp-api/cli/)

• API Console (hmn.md/wp-api/console/)

• WP JSON API Connect (hmn.md/wp-api/connect/)

Other resources
• Picard React theme (hmn.md/wp-api/picard/)

• Feeling Restful theme (hmn.md/wp-api/feeling-

restful/)
• ustwo.com frontend (hmn.md/wp-api/ustwo/)
TALKING TO 25% OF THE WEB / A DAY OF REST 43

Image credit: Florian Ziegler

A Day of REST

Join the REST API team along with speakers from

WIRED, Automattic, The New York Times, and
Bocoup, at A Day of REST, a one-day conference
where you can learn how to use the REST API in your
project: Conway Hall, London. 28th January 2016.
TALKING TO 25% OF THE WEB / WORK WITH US 44

Work with us

Human Made is an enterprise-level WordPress Want to use the WordPress REST API in
development firm, based in the UK but with your project? Contact Human Made for:
employees and clients worldwide.
• enterprise-level development
Our clients include NewsUK, AirBnB, Skype, • bespoke training
and Yell. We’re the people behind Nomadbase • consultancy
and Happytables. Our developers have led • hosting
the development of the WordPress REST API
and we’re already making use of it in our own Email us hello@hmn.md or give us a
products and in client projects. call at +44 (0) 1629 628082

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