Source: https://developers.google.com/style/periods\n\n# Periods and other end punctuation
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Save and categorize content based on your preferences.\n\n- Home\n- Products\n- Style\n\n\n## Page Summary\n\n- Always end complete sentences with a period, except in lists or headings.\n- When including URLs, avoid placing them at the end of a sentence to prevent confusion with the period.\n- For quotations, place the period inside the quotation marks, even if it's not part of the quoted material.\n- In parentheses, if it encloses a full sentence, the period goes inside; if it's part of a larger sentence, the period goes outside.\n- Use periods for decimal points and abbreviations but not for acronyms, headings, or generally in captions.\n\nAlways end complete sentences with a period, except in lists or headings.\n\nWhen including URLs, avoid placing them at the end of a sentence to prevent confusion with the period.\n\nFor quotations, place the period inside the quotation marks, even if it's not part of the quoted material.\n\nIn parentheses, if it encloses a full sentence, the period goes inside; if it's part of a larger sentence, the period goes outside.\n\nUse periods for decimal points and abbreviations but not for acronyms, headings, or generally in captions.\n\nEnd a complete sentence with a period, unless it's a question. There are
exceptions for working in lists.\n\n\n## Periods with lists\n\nWhether to end a list item with a period depends on several factors, including
the kind of list that the item appears in.\n\nFor details about how to use periods in lists, see the
Capitalization and end punctuation
section of the "Lists" page.\n\n\n## Periods with URLs\n\nWhen a period immediately follows a URL or a file path, it can be hard to
tell whether the period is part of the URL.\n\nTo indicate that the punctuating period isn't part of the URL, try one of the
following techniques:\n\n- Whenever possible, avoid putting URLs in text.\n- Rewrite the sentence so that the URL isn't at the end of the sentence.\n- Put the URL on a separate line from the text, omitting the final period.\n\nIf the URL is a link, it generally looks different from the surrounding text. For
example, in most browsers, link text is blue by default. This formatting helps
distinguish the URL from the period.\n\nRecommended:\n\nWe use your feedback to improve the Animals API, in accordance with Example
Pet Store's Privacy Policy:\n\nhttp://www.examplepetstore.com/privacy/\n\nNot recommended:\n\nWe use your feedback to improve the Animals API, in accordance with Example
Pet Store's Privacy Policy at http://www.examplepetstore.com/privacy/.\n\nWhen you do put a period after a URL, don't leave any space between the last character of
the URL and the period.\n\n\n## Periods with quotation marks\n\nWhen a sentence ends with material inside quotation marks, place the period
inside the quotation marks even if the period isn't part of the material inside
the quotation marks. An exception to this guideline applies if you're using quotation marks around
a keyword or other literal string. For more information, see
Commas and periods with quotation marks.\n\nRecommended: ... you might say "Fixed typo."\n\nIf the material inside the quotation marks ends with a question mark or an
exclamation point, don't use a period.\n\nRecommended: Children always ask "Why?"\n\n\n## Periods with parentheses\n\nIf the last part of a sentence is contained inside parentheses, put the
period after the closing parenthesis.\n\nIf the parentheses contain a complete sentence, put the period inside
the parentheses.\n\nRecommended: Your application could show
a notification when a relevant file or folder has changed (even if that change
occurs while your application isn't running).\n\nRecommended: App Engine applications are
easy to create, easy to maintain, and easy to scale. (With App Engine, there are
no servers for you to maintain.)\n\nFor more information, see Parentheses.\n\n\n## Periods with headings\n\nDon't end headings with periods.\n\nFor more information, see Headings.\n\n\n## Periods with numbers\n\nUse a period to represent a decimal point. (Using a comma to separate the decimal part
of a number is the editorial custom in some countries, but not in the US.)\n\nFor more information, see Numbers.\n\n\n## Periods with captions\n\nSee Figure captions.\n\n\n## Periods with alt text\n\nSee Alt text.\n\n\n## Periods with abbreviations\n\nPut a period after a shortened word.\n\nDon't put periods after the letters of an acronym or initialism.\n\nFor more information, see Abbreviations.\n\n\n## Spaces between sentences\n\nLeave only one space between sentences.\n\n\n## Exclamation points\n\nIn general, avoid exclamation points. They can appear unprofessional, alarming, or translate poorly into other languages. If you need to use an exclamation point, see the following guidance by content type:\n\n- Concept and reference docs. Never use exclamation points. These sections should maintain a neutral, objective tone.\n- Procedural topics. Avoid exclamation points. Use periods for completion steps—for example, "The VM is created."\n- Blog posts. Exclamation points are acceptable to convey enthusiasm but shouldn't be used in every paragraph.\n\nWhen exclamation points are acceptable:\n\n- Code examples. Use when required by syntax—for example, the != operator.\n- System literals. Use when an exclamation point is part of a specific error code or log message that must be matched exactly.\n- Tutorials and learning modules. Use sparingly to mark major milestones or achievements—for example, "Congratulations! You've completed the setup."\n