---
id: kb-2026-00084
title: Web Storage API
schema_type: TechArticle
category: computer-science
language: en
confidence: medium
last_verified: '2026-05-28'
created_date: '2026-05-22'
generation_method: human_only
derived_from_human_seed: true
conflict_of_interest: none_declared
is_live_document: false
data_period: static
atomic_facts:
  - id: fact-computer-science-001
    statement: >-
      The HTML Standard defines web storage mechanisms for storing name-value pairs on the client
      side.
    source_title: 'HTML Standard: Web storage'
    source_url: https://html.spec.whatwg.org/multipage/webstorage.html
    confidence: medium
  - id: fact-computer-science-002
    statement: MDN documents localStorage as storage that persists across browser sessions for an origin.
    source_title: 'Window: localStorage property - Web APIs | MDN'
    source_url: https://developer.mozilla.org/en-US/docs/Web/API/Window/localStorage
    confidence: medium
  - id: fact-computer-science-003
    statement: MDN documents sessionStorage as storage partitioned by origin and browser tab session.
    source_title: 'Window: sessionStorage property - Web APIs | MDN'
    source_url: https://developer.mozilla.org/en-US/docs/Web/API/Window/sessionStorage
    confidence: medium
completeness: 0.88
known_gaps:
  - >-
    Coverage intentionally narrowed to directly sourced public evidence; adjacent subtopics are not
    exhaustively covered.
disputed_statements: []
primary_sources:
  - title: 'HTML Standard: Web storage'
    type: standard
    year: 2026
    url: https://html.spec.whatwg.org/multipage/webstorage.html
    institution: WHATWG
  - title: 'Window: localStorage property - Web APIs | MDN'
    type: documentation
    year: 2025
    url: https://developer.mozilla.org/en-US/docs/Web/API/Window/localStorage
    institution: Mozilla
  - title: 'Window: sessionStorage property - Web APIs | MDN'
    type: documentation
    year: 2025
    url: https://developer.mozilla.org/en-US/docs/Web/API/Window/sessionStorage
    institution: Mozilla
secondary_sources: []
updated: '2026-05-28'
---
## TL;DR

The Web Storage API provides browser-side key-value storage through localStorage and sessionStorage. This repair removes quota and performance claims and keeps to the HTML Standard and MDN references.

## Core Explanation

The stable distinction is that sessionStorage is scoped to a page session, while localStorage persists for an origin beyond the current session. Both expose the Storage interface for string key-value data.

## Further Reading

- [HTML Standard: Web storage](https://html.spec.whatwg.org/multipage/webstorage.html)
- [Window: localStorage property - Web APIs | MDN](https://developer.mozilla.org/en-US/docs/Web/API/Window/localStorage)
- [Window: sessionStorage property - Web APIs | MDN](https://developer.mozilla.org/en-US/docs/Web/API/Window/sessionStorage)

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