How would you design Lenskart in a system design interview?

Treat each order as a job. Check the prescription before payment. Route the lenses: stock for common powers, a lab for the rest. Track the job through each station as a state machine, where a failed check goes back one step. Share one customer profile and one stock service across stores and online.

How many stores does Lenskart have?

2,723 in its July 2025 draft prospectus, as reported by Business Standard: 2,067 in India and 656 abroad.

How are prescription glasses made after an online order?

In a design like this, a frame is picked. The lenses come from stock or are made in a lab. Each lens is cut to the frame's shape and turned to the right axis. Then the pair is fitted, checked against the prescription, packed and shipped.

How do you validate an eyeglass prescription in software?

Check each value is in its allowed range and on a 0.25 step. Make AXIS required when CYL is not zero, and keep it between 1 and 180. Send odd cases, like a big difference between the eyes, to a person.

Where does Lenskart make its glasses?

Business Standard reported on the July 2025 draft prospectus. It lists plants in Bhiwadi and Gurugram, with regional hubs in Singapore and the UAE.

What tech stack does Lenskart use?

Lenskart has not published its stack in the sources read for this page. For the interview, the shape matters more than the tools. Use a state machine for jobs, a queue per lab, encrypted prescriptions and one shared stock service.

System design interview guide

Lenskart System Design: Prescriptions, Lens Labs and Stores as One System

Short answer

Lenskart system design treats every order as a small manufacturing job. The prescription is checked before payment: ranges, 0.25 steps, and AXIS whenever CYL is set. A routing step picks the lens path. Common powers come from stock, and the rest go to a lab queue. A job service tracks the pair through stations as a state machine. The states are frame picked, lenses ready, cut, fitted, checked, packed and shipped. A failed check goes back one step. One customer profile and one stock service serve stores, app and website. So a store eye test can turn into an online order.

in this guide

Design Lenskart, part by part

8 parts open to everyone · 3 with a free account · 3 with the course

You can read 8 of 14 parts. A free account opens the deep dive; the course opens all of it.

Requirementsopen
Scale estimatesopen

Why this question is asked

It moves the interview past the shopping cart. Payment is the easy part. The hard part starts after it. A design that treats the order as one database row breaks here. The order goes through a lab and a quality check, and some steps can fail and repeat. The question tests whether you can model a long-running job as a state machine. It also tests validating medical input, and routing work to the right site. And it tests serving one customer across stores, app and website as one person.

This page is the free part.

The course goes deeper on the Lenskart design

₹1,111 in India$25 everywhere elseonce, for the whole course

The System Design course covers the Lenskart design across a run of lessons, not one page. These 4 alone are about 93 minutes of step-by-step reading, 2 of them with code you run in the browser, all with a quiz.

Requirements

Always clarify these in the first 5 minutes of the interview. Do not start drawing boxes until both lists are agreed.

Functional requirements

Browse frames, try them on with the phone camera, and pick lenses
Enter a prescription, upload a photo of one, or use one from a store eye test
Check the prescription for values that cannot be right before payment

Go deeper

This guide is built on these 6 lessons. Each one teaches one piece of the Lenskart design above, step by step.

Practice with 770 system design lessons

Lifetime access for ₹1,111 in India or $25 elsewhere. Interactive diagrams, quizzes, and 20 capstone projects to practise on.

Get lifetime access See all interview problems

Two courses by the author of this page:

System Design

770 lessons · 18 free to read

₹1,111 in India · $25 elsewhere, once

Get System Design

You own this course

Generative AI and Agentic AI

214 lessons · 10 free to read

₹1,333 in India · $35 elsewhere, once

Get Generative AI and Agentic AI

You own this course

Every lesson in both courses has an AI tutor beside it. It reads the same lesson you are reading and answers your questions from it. Try the tutor

Save your progress and get the interview checklist PDF

System Design Interview Cheat Sheet: the 7 interview stages, the 10 points a scorecard grades, 12 classic systems. 18 pages. Free with an account.

Lenskart's July 2025 draft prospectus lists 2,723 stores. 2,067 are in India and 656 are abroad. In the year to March 2025 its revenue from operations was Rs 6,652.5 crore. It makes frames and lenses in its own plants in Bhiwadi and Gurugram. So a pair of glasses is not picked off a shelf like a T-shirt. Most orders are a small manufacturing job. A frame, two lenses ground to one person's prescription, cut to that frame's shape, fitted and checked.

Lenskart sells glasses, sunglasses and contact lenses in India and abroad. It sells online and in its own stores. A design like Lenskart's has three parts that a normal shop does not. First, the prescription. It is medical data with a strict format, and a wrong number means glasses that give headaches. Second, the lens. Common powers are kept in stock. Unusual powers and special lenses must be made in a lab. So each order must decide which path it takes. Third, the order is a job with many steps. Pick the frame, get the lenses, cut, fit, check, pack and ship. Every step can fail and must be tracked. On top sits omnichannel. A customer may get an eye test in a store, then buy online, or try frames at home first.

Roni Das

25 October 2026 · 15 min read

Where it shows up

A natural question for retail, D2C and supply-chain roles in India. Think of Lenskart, Titan Eye+ and Warby Parker. The general forms are: design a made-to-order shop, or an order pipeline with manufacturing steps. Another is stores and online sharing stock.

Spec sheetLenskart

01Stores: 2,723 (2,067 in India)
02Revenue per day: ~Rs 18.2 crore
03Orders per day (estimate): ~73,000
04Orders per peak hour: ~9,100

worked through below, with the maths

Data modelfree account

Deep dives (6)free account

Unlock with the course · $25One payment, lifetime access to every lesson.

The hard parts of this design are taught step by step in the System Design course: State Machine, Event Sourcing and Priority Queue.

State Machine
Model system behavior as a finite set of states and transitions, the foundation of distributed protocols.
25 min · diagrams · code you run · quiz
Event Sourcing
Store events instead of state, rebuild any point in time from the log of what happened.
30 min · diagrams · code you run · quiz
Priority Queue
Not all messages are equal, process the urgent ones first.
18 min · diagrams · quiz
Message Queues
Decouple producers from consumers with a buffer that holds messages until they're processed.
20 min · diagrams · quiz

all part of

System Design Masterclass

770 lessons · about 287 hours · 18 free to read

₹1,111in India, by UPI

$25everywhere else, by PayPal

Get the System Design course Read 18 lessons free first

You own this course

Continue with State Machine

pay once,
yours for life

Live from the course bench

Before you design Lenskart, try the questions it rests on.

Real interview questions, live diagrams and measured lab results, pulled at random from the lessons. A new set every time you come back.

Two engineers sketching a system design on a whiteboard

where the work happens

Stuck on a card?

Ask the course tutor. It answers with a real diagram, drawn for your question.

Ask the tutor

Laying out the cards…

Decide if the lenses come from stock or must be made in a lab

Track each order through picking, lens making, cutting, fitting, checking and shipping

Let a store sell any frame from central stock and deliver it to the customer

Book an eye test at home or in a store, and save the result to the customer's profile

Non-functional requirements

A wrong prescription must be caught before a lens is made, not after
Every job must be traceable step by step, with who did what
A slow lab must not stop orders that use stock lenses
Stores, app and website see the same customer and the same prescriptions
Prescriptions are health data: encrypted and access-logged

Back-of-envelope scale estimates

Show your math. Pulling numbers from thin air signals you have not thought about the load.

Stores

2,723 (2,067 in India)

The July 2025 draft prospectus, as reported by Business Standard, lists 2,723 stores: 2,067 in India and 656 abroad. 2,723 minus 2,067 is 656. Every store is a place where an order can start and where stock sits.

Revenue per day

~Rs 18.2 crore

Revenue from operations in FY25 was Rs 6,652.5 crore. Divided by 365 days, that is about Rs 18.2 crore a day. This includes all countries.

Orders per day (estimate)

~73,000

Assume an average order of Rs 2,500. Rs 18.2 crore divided by Rs 2,500 is about 72,900 orders a day. The order value is my assumption, not a Lenskart figure. So treat this as the right size, not a count.

Orders per peak hour

~9,100

About 72,900 orders a day is about 3,040 an hour on average. Assume the busiest hour runs at 3 times that. That is about 9,100 orders in the peak hour.

Stock lens types

1,105 per lens type

Assume stock lenses cover SPH from -10.00 to +6.00 and CYL from -4.00 to 0.00. Powers move in 0.25 steps. That is 65 SPH values and 17 CYL values. 65 times 17 is 1,105 SKUs per lens design. The axis is not a separate SKU, because the lens is rotated when it is cut.

Lab jobs per day (example)

~21,900

Assume 30% of orders need lenses made in a lab, because of high power, progressives or special coatings. 30% of about 72,900 is about 21,900 lab jobs a day. The rest use stock lenses and skip the lab.

High-level architecture

Model the order as a job, not a row. The shop front is normal: a catalog, a try-on feature, a cart and payment. The difference starts with the prescription. A prescription service stores each prescription with its source, such as a store test, an uploaded photo or typed values. It checks every value against allowed ranges and steps before payment. Then a routing step decides the lens path. If the power and lens type are in stock, lenses are picked from a store or a warehouse. If not, a job goes to a lab. A job service tracks every order through its steps as a state machine. The steps are frame picked, lenses ready, cut, fitted, checked, packed and shipped. Each step is a scan at a station, recorded as an event. A failed check sends the job back one step, not back to the start. Stores are both shops and stock points. They can sell frames from central stock and have them made and shipped. One customer profile holds prescriptions, past frames and orders, for every channel.

In a real interview, sketch this on the whiteboard before diving into any single box.

One pair of glasses, end to end

A customer had an eye test in a store last month. Now she orders a new frame on the app.

1
The prescription
Her store eye test is already in her profile. She picks it. The service checks its date and its values against allowed ranges.
2
The lens path
Her powers are SPH -2.25 and CYL -0.75, inside the stock range. So the lenses are picked from stock. No lab job is needed.
3
The job starts
Payment succeeds. The job service creates a job in the state frame picked. It goes to the warehouse that has both the frame and the lenses.
4
Cutting and fitting
Each lens is cut to the frame's shape and rotated to her axis. Each step is a scan, so the job moves to cut, then fitted.
5
The check
A checker measures the finished lenses against the prescription. One lens is off. The job goes back to cut for that lens only, then passes.
6
Shipping
The job moves to packed and shipped. She sees each step in the app as it happens.

Core components

Walk through each service. The interviewer wants to hear what each one owns, not just the names.

Catalog and try-on

Frames with measurements: lens width, bridge and temple length. Try-on uses the phone camera to place a frame on the face. It only needs the frame's images or 3D model, served from a CDN.

Prescription service

Stores each prescription with its source and date. Checks every value against allowed ranges and 0.25 steps. Flags combinations that need a person to review, such as a big difference between the two eyes.

Lens routing

Decides if the lenses come from stock or from a lab, and which site does the work. It looks at power range, lens type, coatings and where the frame is.

Job service (state machine)

Tracks each order through its steps. Each scan at a station is an event. A failed check sends the job back one step. Jobs stuck too long in a step raise an alert.

Lab work queue

Lab jobs wait in a queue per lab and per machine type. Rush jobs can go first. A slow lab only delays lab jobs, not stock-lens orders.

Stock service

Frames and stock lenses per site: warehouses, labs and stores. A store can sell a frame it does not hold, from central stock.

Customer profile

One profile across stores, app and website. It holds prescriptions, past frames, face measurements and orders. Prescriptions are encrypted and every read is logged.

the deep dive

Data model

prescriptions. OD is the right eye and OS the left. Values are checked against ranges and 0.25 steps. Health data: encrypted at rest.

free with an account

Every table for Lenskart, its keys, and which store fits it and why.

One tap with Google. Free, no card.

the deep dive

Deep dives

A prescription is data that must be checked. A prescription has a few numbers for each eye. SPH is the main power. CYL corrects astigmatism, and AXIS is its angle from 1 to 180. ADD is extra power for reading, and…

free with an account

6 deep dives on the parts that break at scale, with 2 diagrams: A prescription is data that must be checked; Stock lenses or a lab job; The order is a job with many steps.

One tap with Google. Free, no card.

the deep dive

Trade-offs to discuss

Stock lenses versus making every lens in a lab. Making every lens to order needs no lens stock and covers every power. But it is slow and costly for common powers. Stocking common powers gives a fast path for most…

free with an account

4 decisions an interviewer expects you to defend, each with the alternative and why it loses here.

One tap with Google. Free, no card.

for course owners

What the interviewer asks next

What if the customer uploads a photo of a prescription?

with the System Design course

3 follow-up questions with model answers, the interview scorecard for this question, and a mock interview on Design Lenskart with the AI tutor.

Unlock with the course · $25One payment, lifetime access to every lesson.

How Lenskart actually does it

Lenskart has not published how its systems are built in the sources read for this page. So the design here fits public facts; it is not a description of Lenskart's code. Business Standard reported the July 2025 draft prospectus. It lists 2,723 stores, 2,067 in India and 656 abroad, and FY25 revenue from operations of Rs 6,652.5 crore. It also lists plants in Bhiwadi and Gurugram with regional hubs in Singapore and the UAE. Nearly 45% of India revenue came from customers who engaged digitally within 90 days before purchase. The order count, lens ranges and lab share on this page are interview assumptions.

Sources

Business Standard (July 2025): Lenskart files for IPO, details from the draft prospectus

Was this helpful?

System design interviews at Indian tech companies

28 walkthroughs of the products Indian interviewers ask about, each with the real scale numbers, the architecture and the trade-offs that company had to make.

Food delivery and quick commerce

Payments and fintech

E-commerce

Travel and ticketing

Rides, logistics and services

Streaming and gaming

the question most readers have next

What would you have to get right to run the Lenskart design for real users?

The design on this page is the shape. Running it means handling the failures, the load and the data that the shape does not show. The lessons below teach those parts, starting with "State Machine".

Where this is used in industry

The real examples, each with its source, are on this page: How Lenskart actually does it.

The lessons that teach the next part

Model system behavior as a finite set of states and transitions, the foundation of distributed protocols.
State MachineSystem Design course25 min
Store events instead of state, rebuild any point in time from the log of what happened.
Event SourcingSystem Design course30 min
Not all messages are equal, process the urgent ones first.
Priority QueueSystem Design course18 min
Decouple producers from consumers with a buffer that holds messages until they're processed.
Message QueuesSystem Design course20 min

Stuck on a step? Every lesson has an AI tutor beside it. Ask it your question and it answers from the lesson you are reading. Try the tutor

Get the free System Design Interview cheat sheet (PDF)

Where this is taught

System Design Masterclass

770 lessons · about 287 hours · 18 free to read

₹1,111 in India by UPI$25 elsewhere by PayPal, once, for life

See the System Design course

You own this course

Frequently asked questions

India: UPI, cards or netbanking through Razorpay. Elsewhere: card or PayPal. Download at once from My packs.

NEWSystem Design Hands-On

Included in the System Design course: real systems, built live

Postgres Sharding: Complete Hands-On (PgBouncer + Citus). 2 h 36 min and 20 chapters: one PostgreSQL loaded until it breaks, then four shards behind a router you write, PgBouncer and Citus, with the 139-page slide deck. The first 15 minutes are free to watch.

Watch the free 15 minutes See System Design Hands-On

Free PDF · 79 pages

25 real tech interview questions, answered in full

Five from each of our AI, GenAI, Inference, Maths for ML and Forward Deployed packs. Each with a diagram and a model answer. Free by email.

free tool

Check these numbers yourself

Put in your own guesses for Lenskart and see requests per second, storage, bandwidth and servers, with every sum written out.

Open the Capacity Estimator

Also by the same author

214 lessons · about 224 hours · 10 free to read

₹1,333 in India by UPI$35 elsewhere by PayPal, once, for life

See the Generative AI and Agentic AI course

what a reader said

It is really nice and good Please join the course

Gyan Kumar, Analyst, Bangalore · System Design Masterclass · read 3 lessons · all reviews

Lenskart System Design: Prescriptions, Lens Labs and Stores as One System

Design Lenskart, part by part

Why this question is asked

The course goes deeper on the Lenskart design

Requirements

Functional requirements

Go deeper

Practice with 770 system design lessons

Get all 200 questions in the System Design and Distributed Systems pack

Before you design Lenskart, try the questions it rests on.

Non-functional requirements

Back-of-envelope scale estimates

High-level architecture

One pair of glasses, end to end

The prescription

The lens path

The job starts

Cutting and fitting

The check

Shipping

Core components

Catalog and try-on

Prescription service

Lens routing

Job service (state machine)

Lab work queue

Stock service

Customer profile

Data model

Deep dives

Trade-offs to discuss

What the interviewer asks next

How Lenskart actually does it

Lessons to study before this interview

Related system design interview questions

System design interviews at Indian tech companies

Food delivery and quick commerce

Payments and fintech

E-commerce

Travel and ticketing

Rides, logistics and services

Streaming and gaming

What would you have to get right to run the Lenskart design for real users?

Where this is used in industry

The lessons that teach the next part

Frequently asked questions

How would you design Lenskart in a system design interview?

How many stores does Lenskart have?

How are prescription glasses made after an online order?

How do you validate an eyeglass prescription in software?

Where does Lenskart make its glasses?

What tech stack does Lenskart use?

Are you ready for Design Lenskart?

Included in the System Design course: real systems, built live