What is IndexedDB?

IndexedDB is a built-in browser feature that lets web pages store lots of structured data (like records in a tiny database) right on a user’s device. It works even when the user is offline and can handle large amounts of information efficiently.

Let's break it down

  • Built-in browser feature: It comes with Chrome, Firefox, Safari, etc., no extra software needed.
  • Store lots of structured data: You can save objects, numbers, text, or even files in an organized way, similar to rows in a spreadsheet.
  • Right on a user’s device: The data lives on the computer or phone, not on a remote server.
  • Works offline: Pages can read and write data even without an internet connection.
  • Handle large amounts: Unlike cookies or localStorage, IndexedDB can hold megabytes or even gigabytes of data.

Why does it matter?

Because it lets web apps run faster, stay functional without internet, and keep user data private on the device. This makes experiences like games, productivity tools, and media editors feel more like native apps.

Where is it used?

  • Progressive Web Apps (PWAs) such as offline-first note-taking tools that sync later.
  • Browser-based games that need to save player progress, high scores, or large asset files.
  • Email or chat clients that cache messages so you can read them without being online.
  • Data-heavy visualization tools that store fetched datasets locally to avoid re-downloading.

Good things about it

  • Stores large amounts of data (far more than cookies or localStorage).
  • Works asynchronously, so it doesn’t freeze the page while reading or writing.
  • Supports complex queries and indexes, making data retrieval fast.
  • Works offline, enabling true “offline-first” experiences.
  • Data is sandboxed per origin, keeping other sites from accessing it.

Not-so-good things

  • API is verbose and can be hard for beginners to learn.
  • Debugging can be tricky because data is stored inside the browser’s internal storage.
  • Not all older browsers fully support it, so fallback code may be needed.
  • Because it runs in the browser, very large datasets can still impact performance or device storage limits.