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Social media · Photo sharing

Instagram-style app

Illustrative system design for a photo sharing app like Instagram: 6 topics to read, from requirements to deep dives.

Endless feeds someone else is writing to while you read.

Illustrative design, not Instagram’s actual implementation. Arrowbox is not affiliated with Instagram’s owner. Disclaimer

Start with Login Read for freeUpdated 2 Oct 2026

Onboarding

  • Email and password loginBeginner · 19 min read

    The web login form: email or username plus password, a session cookie, and a safe redirect.

  • Phone number and OTP loginIntermediate · 36 min read

    Passwordless web login: number entry, a 6-digit SMS code the browser can fill, and resend limits.

  • Profile picture uploadIntermediate · 45 min read

    Pick, circle-crop, compress in a worker and upload with progress, retry and an instant avatar swap.

Feed

  • Infinite photo feedIntermediate · 48 min read

    Image-first home feed: responsive images, blur-up placeholders, cursor paging and scroll restore.

  • Stories viewerAdvanced · 46 min read

    Tray to full-screen viewer: timed segments, tap and hold, preloading the next story, seen state.

Create

  • Crop and filterAdvanced · 46 min read

    Post editor: aspect crop, filter presets and sliders on a GPU preview, full-quality export off-thread.