Folio — EditionSakina Saifuddin© 2026
2021

A journey through code, data, and intelligent systems.

Folio — EditionSakina Saifuddin© 2026
SS
01Intro02Work03What I Build04Achievements05Experience06Expertise07Contact
Case studyClick a page, swipe, or use ← → to turn

FITNESS APPVIDEO LOADINGFIX

FITNESS VIDEO

  • Workout videos took about 5 minutes to load.
  • I found the bottleneck and moved the videos to AWS S3.
  • Videos now start in about 3 seconds.
5 min → 3 secloading time
50+workout videos
Visit the portfolio
website at:sakina-saifuddin / works
23223
Fitness VideoSakina Saifuddin

FITNESS APPVIDEO LOADINGFIX

Videos took minutes to start
Fig. 1 — A frame from the real app.1
  1. Task
  2. My work
  3. Results
  4. Outcome

Videos took minutes to start

  • The app has 50+ workout videos.
  • Each one took about 5 minutes to load.
  • The app felt broken.
~5 minto load one video
2
Found the bottleneck, fixed delivery
Fig. 2 — The delay came from video delivery.3
  1. Task
  2. My work
  3. Results
  4. Outcome

Found the bottleneck, fixed delivery

  • Traced the delay to the old video-loading setup.
  • Moved every video to AWS S3.
  • Updated the app to load videos from S3.

Tools: React Native · Node.js · AWS S3

4
Videos start almost instantly
Fig. 3 — Videos now start in seconds.5
  1. Task
  2. My work
  3. Results
  4. Outcome

Videos start almost instantly

~5 minbefore
~3 secafter
50+videos sped up
6
The app finally feels fast
Fig. 4 — Workouts start right away.7
  1. Task
  2. My work
  3. Results
  4. Outcome

The app finally feels fast

  • Users start a workout right away.
  • Solved with debugging and cloud storage.
  • Times can vary by network and device.
8
9

Technologies

React Native
The mobile app.
Node.js
The backend.
AWS S3
Stores and delivers the videos.
What I did
  • Diagnosed the loading bottleneck.
  • Moved the video library to AWS S3.
  • Updated the app and backend.
10

FITNESS VIDEO

  • Workout videos took about 5 minutes to load.
  • I found the bottleneck and moved the videos to AWS S3.
  • Videos now start in about 3 seconds.
5 min → 3 secloading time
50+workout videos
Visit the portfolio
website at:sakina-saifuddin / works
23223
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