Tutorials System Design Tutorial
Blob Storage Design — Complete Guide
Blob Storage Design — Complete Guide: free step-by-step lesson with examples, common mistakes, and interview tips — part of System Design Tutorial on Toolliyo Academy.
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System Design Tutorial · Lesson 35 of 100
Blob Storage Design
Basics → Scale → Interview
Basics · 1 — Building blocks · ~6 min · Module 4: Caching and Storage
What is this?
Blob/object storage holds large binary objects — images, videos, invoices — addressed by keys, with lifecycle and access policies.
Why should you care?
ShopNest product media must not live as BYTEA in the orders database.
See it live — copy this example
Sketch the architecture on paper. These lessons focus on concepts and trade-offs.
s3://shopnest-media/prod/{productId}/{imageId}.jpg
DB stores URL/key only
Upload: pre-signed PUT from browser
Lifecycle: move old logs to cold tier after 30dRun Example »
Edit the code below and click Run to see the result in Toolliyo’s live editor.
What happened?
- Objects scale independently of OLTP.
- Pre-signed URLs avoid piping all bytes through the API.
- Lifecycle rules control cost.
Practice next
- Store only media keys/URLs in ShopNest SQL.
- Use pre-signed uploads for seller images.
- CDN in front of the bucket for reads.
- Separate public media vs private invoices buckets.
- Virus-scan async after upload.
Remember
Blobs for big files. DB holds pointers. Signed URLs + lifecycle.
ShopNest media bucket
PDP images from object storage via CDN.
Outcome: Database size stays about orders, not megapixels.
Interview prep for this lesson
Practice these questions aloud after reading—each links to a full structured answer.
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