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Version: v4.15.x

Fastify Style Guide


Welcome to Fastify Style Guide. This guide is here to provide you with a conventional writing style for users writing developer documentation on our Open Source framework. Each topic is precise and well explained to help you write documentation users can easily understand and implement.

Who is this guide for?

This guide is for anyone who loves to build with Fastify or wants to contribute to our documentation. You do not need to be an expert in writing technical documentation. This guide is here to help you.

Visit the contribute page on our website or read the file on GitHub to join our Open Source folks.

Before you write

You need to know the following:

  • JavaScript
  • Node.js
  • Git
  • GitHub
  • Markdown
  • HTTP
  • NPM

Consider your Audience

Before you start writing, think about your audience. In this case, your audience should already know HTTP, JavaScript, NPM, and Node.js. It is necessary to keep your readers in mind because they are the ones consuming your content. You want to give as much useful information as possible. Consider the vital things they need to know and how they can understand them. Use words and references that readers can relate to easily. Ask for feedback from the community, it can help you write better documentation that focuses on the user and what you want to achieve.

Get straight to the point

Give your readers a clear and precise action to take. Start with what is most important. This way, you can help them find what they need faster. Mostly, readers tend to read the first content on a page, and many will not scroll further.


Less like this: Colons are very important to register a parametric path. It lets the framework know there is a new parameter created. You can place the colon before the parameter name so the parametric path can be created.

More Like this: To register a parametric path, put a colon before the parameter name. Using a colon lets the framework know it is a parametric path and not a static path.

Avoid adding video or image content

Do not add videos or screenshots to the documentation. It is easier to keep under version control. Videos and images will eventually end up becoming outdated as new updates keep developing. Instead, make a referral link or a YouTube video. You can add links by using [Title]( in the markdown.


To learn more about hooks, see [Fastify hooks](


To learn more about hooks, see Fastify hooks.

Avoid plagiarism

Make sure you avoid copying other people's work. Keep it as original as possible. You can learn from what they have done and reference where it is from if you used a particular quote from their work.

Word Choice

There are a few things you need to use and avoid when writing your documentation to improve readability for readers and make documentation neat, direct, and clean.

When to use the second person "you" as the pronoun

When writing articles or guides, your content should communicate directly to readers in the second person ("you") addressed form. It is easier to give them direct instruction on what to do on a particular topic. To see an example, visit the Plugins Guide.


Less like this: we can use the following plugins.

More like this: You can use the following plugins.

According to Wikipedia, You is usually a second person pronoun. Also, used to refer to an indeterminate person, as a more common alternative to a very formal indefinite pronoun.

When to avoid the second person "you" as the pronoun

One of the main rules of formal writing such as reference documentation, or API documentation, is to avoid the second person ("you") or directly addressing the reader.


Less like this: You can use the following recommendation as an example.

More like this: As an example, the following recommendations should be referenced.

To view a live example, refer to the Decorators reference document.

Avoid using contractions

Contractions are the shortened version of written and spoken forms of a word, i.e. using "don't" instead of "do not". Avoid contractions to provide a more formal tone.

Avoid using condescending terms

Condescending terms are words that include:

  • Just
  • Easy
  • Simply
  • Basically
  • Obviously

The reader may not find it easy to use Fastify's framework and plugins; avoid words that make it sound simple, easy, offensive, or insensitive. Not everyone who reads the documentation has the same level of understanding.

Starting with a verb

Mostly start your description with a verb, which makes it simple and precise for the reader to follow. Prefer using present tense because it is easier to read and understand than the past or future tense.


Less like this: There is a need for Node.js to be installed before you can be able to use Fastify.

More like this: Install Node.js to make use of Fastify.

Grammatical moods

Grammatical moods are a great way to express your writing. Avoid sounding too bossy while making a direct statement. Know when to switch between indicative, imperative, and subjunctive moods.

Indicative - Use when making a factual statement or question.

Example: Since there is no testing framework available, "Fastify recommends ways to write tests".

Imperative - Use when giving instructions, actions, commands, or when you write your headings.

Example: Install dependencies before starting development.

Subjunctive - Use when making suggestions, hypotheses, or non-factual statements.

Example: Reading the documentation on our website is recommended to get comprehensive knowledge of the framework.

Use active voice instead of passive

Using active voice is a more compact and direct way of conveying your documentation.


Passive: The node dependencies and packages are installed by npm.

Active: npm installs packages and node dependencies.

Writing Style

Documentation titles

When creating a new guide, API, or reference in the /docs/ directory, use short titles that best describe the topic of your documentation. Name your files in kebab-cases and avoid Raw or camelCase. To learn more about kebab-case you can visit this medium article on Case Styles.


Hyperlinks should have a clear title of what it references. Here is how your hyperlink should look:

<!-- More like this -->

// Add clear & brief description
[Fastify Plugins] (

<!--Less like this -->

// incomplete description
[Fastify] (

// Adding title in link brackets
[]( "fastify plugin")

// Empty title

// Adding links localhost URLs instead of using code strings (``)

Include in your documentation as many essential references as possible, but avoid having numerous links when writing for beginners to avoid distractions.