Follow the standard capitalization rules for American English. Additionally:

  • Follow the official capitalization for the names of brands, companies, software, products, services, and terms defined by companies and open source communities.

    • For example, if you're using Kubernetes-related terms, then follow the capitalization shown in the Kubernetes Concepts documentation.

      Recommended in a Kubernetes context: A Job creates one or more Pods.

      Recommended: The Cloud Scheduler job publishes a message to a Cloud Pub/Sub topic at one-minute intervals.

    • If an official name begins with a lowercase letter, then put it in lowercase even at the start of a sentence. But it's better to revise the sentence to avoid putting a lowercase word at the start, if possible.
  • Don't use all-uppercase, except in the following contexts: in official names, in abbreviations that are always written in all-caps, or when referring to code that uses all-caps.
  • Don't use camel case, except in official names or when referring to code that uses camel case.

Capitalization in titles and headings

In document titles and headings, use sentence case. That is, capitalize only the first word in the title, the first word in a subheading after a colon, and any proper nouns or other terms that are always capitalized a certain way.

Even though you're using sentence case, don't put a period at the end of a title or heading.

Capitalization in references to titles and headings

In references to any title or heading from a document that follows this guide, use sentence case even if the title or heading itself uses title case. That way, when the title or heading is eventually updated to sentence case, the reference will match.

When you reference the title of any work or source that doesn't follow this guide, retain the original capitalization. For more information about formatting references to third-party sources, see Formatting cross-references and HTML and semantic tagging.

For more information about internal and external references, see Cross-references.

Capitalization and colons

Use a lowercase letter to begin the first word of the text immediately following a colon, unless the text is one of the following:

  • A proper noun (Open source software: Istio).
  • A heading. See also Capitalization in titles and headings.
  • A quotation (Arthurian wit: "Bring me yon sworde").
  • Text that follows a label such as Caution or Note.

Capitalization and figures

Use sentence case for captions. Use sentence case for labels, callouts, and other text in images and diagrams.

Capitalization in glossaries and indexes

Use lowercase for glossary and index terms unless the term is a proper noun or has another reason to require capitalization.

Use sentence case for glossary definitions.

Capitalization and hyphenated words

When a hyphenated word is the first word in a sentence or in a heading, capitalize only the first element in the word, unless a subsequent element is a proper noun or proper adjective.

Capitalization in lists

Use sentence case for items in all types of lists. For more information, see Capitalization and end punctuation on the Lists page.

Capitalization for tables in text

Use sentence case for all the elements in a table: contents, headings, labels, and captions.