Product Manager Interviews Module 2 – Product sense and product design

Designing products for users in India

Design for users in India: size device, network, language and payment limits with official data, then choose app, voice, missed-call or assisted channels.

Intermediate
15 minutes
Examples run with Python 3.14.8, Pyodide 314.0.7 and sql.js 1.14.2
By MySmartCoPilot

Free: Four constraints change the design: device, network, language and payment · Size a constraint with the official numbers, not a guess · Choose the channel from the group's constraints · Practise: choose a channel for three groups. With a pass: 2 in-depth parts and 3 interview answers, about 9 minutes.

What you will learn

Identify the device, network, language and payment constraints that change a design
Choose between app, voice, missed-call and assisted channels for a user group
Size a constraint with official data instead of a guess
Design one feature for a multilingual user group with patchy connectivity

Before you start

Designing a product for a user group

What you’ll learn · Before you start

What you will learn

Identify the device, network, language and payment constraints that change a design
Choose between app, voice, missed-call and assisted channels for a user group
Size a constraint with official data instead of a guess
Design one feature for a multilingual user group with patchy connectivity

Before you start

Designing a product for a user group

On this page

India’s telecom regulator counts 155 telephone subscriptions for every 100 people in cities and 61 in villages. A design that assumes a smartphone of one’s own, steady data and English screens loses many users before the first screen; one that starts from their device, network, language and way of paying keeps them.

This page names those four constraints with the official figures behind them, sizes one with a program, and chooses between an app, a voice menu, a missed call and assisted use for a user group. Two complete designs, and the channel choice worked through with the numbers, follow.

Four constraints change the design: device, network, language and payment

Start every design for Indian users with four questions, each with an official figure to anchor it:

Constraint	What to ask	The official anchor
Device	A basic or a smart phone, shared or owned, with storage to spare or not	The central bank’s count of feature-phone subscriptions, below
Network	Whether data is steady and affordable	TRAI, the telecom regulator: about 1,101 million broadband subscriptions, 1,010 million without machine connections such as card readers
Language	The script people read and type, or whether they speak instead	The Eighth Schedule of the Constitution lists 22 languages
Payment	Which ways to pay work on the user’s phone	Four ways to pay from a basic phone, below

Payments on basic phones

The Reserve Bank of India’s release that introduced UPI123Pay put the number of feature-phone mobile subscribers at more than 40 crore, and offered them four ways to pay by UPI: an app on the basic phone, a missed call, a voice menu (IVR) and sound-based payments between nearby phones. The same release called the older USSD route, *99#, cumbersome and not popular.

Four smaller questions follow: who else uses the phone, what data costs the user, how much storage your app may take, and who helps when something goes wrong, since a family member or a shopkeeper often does. Accessibility is a fifth constraint, which the next lesson covers with India’s guidelines for government websites and apps.

Size a constraint with the official numbers, not a guess

The regulator’s counts are subscriptions, and a subscription is a connection, not a person: one person may hold two SIMs, and a family may share one phone. The program turns the counts into figures a designer can use, per 100 people of the official population projection:

Telecom counts per 100 people, and what they may stand for Python · constraints/india_constraints.py

"""Telecom counts as a product designer reads them: connections per 100 people in cities and in villages, and how many
people a count of connections may stand for.

Figures in millions, typed in from two official documents:
- TRAI's press release No. 125, Highlights of Telecom Subscription Data, for the month it covers;
- India's projected population for the same year, Tables 8 and 9 of the Report of the Technical Group on
  Population Projections (National Commission on Population).
"""

SUBSCRIPTIONS = {"urban": 802.28, "rural": 558.43}  # telephone subscriptions (TRAI)
PEOPLE = {"urban": 515.197, "rural": 1423.435 - 515.197}  # projected people (urban, and total minus urban)
MOBILE, ACTIVE = 1293.43, 1207.59  # mobile subscriptions, and those active on the peak day (TRAI's VLR count)
RURAL_MOBILE = 544.58  # the rural share of the mobile subscriptions (TRAI)
BROADBAND = {"with M2M": 1101.21, "without M2M": 1010.28}  # M2M: machine connections such as card readers

print("Telephone subscriptions per 100 people")
per_100 = {}
for area in ("urban", "rural"):
    per_100[area] = 100 * SUBSCRIPTIONS[area] / PEOPLE[area]
    print(f"  {area:5}  {per_100[area]:5.1f}   ({SUBSCRIPTIONS[area]:.1f} million subscriptions, {PEOPLE[area]:.1f} million people)")
print(f"  a city dweller has {per_100['urban'] / per_100['rural']:.1f} times as many subscriptions as a villager")

everyone = sum(PEOPLE.values())
for kind, millions in BROADBAND.items():
    print(f"Broadband subscriptions per 100 people, {kind}: {100 * millions / everyone:.1f}")
print(f"Mobile subscriptions not active on the peak day: {100 * (1 - ACTIVE / MOBILE):.1f} %")

# A subscription is a connection, not a person: someone with two SIMs counts twice. The shares below are
# assumptions to show the range, not measurements; a survey of your own user group replaces them.
print("\nPeople with an active mobile phone of their own, per 100 villagers, if this share of them holds two SIMs")
for two_sims in (0.0, 0.2, 0.4):
    owners = 100 * RURAL_MOBILE * (ACTIVE / MOBILE) / PEOPLE["rural"] / (1 + two_sims)
    print(f"  {100 * two_sims:3.0f} % with two SIMs: {owners:4.1f}")
print("A shared family phone works the other way: one subscription, several users.")

Output

Telephone subscriptions per 100 people
  urban  155.7   (802.3 million subscriptions, 515.2 million people)
  rural   61.5   (558.4 million subscriptions, 908.2 million people)
  a city dweller has 2.5 times as many subscriptions as a villager
Broadband subscriptions per 100 people, with M2M: 77.4
Broadband subscriptions per 100 people, without M2M: 71.0
Mobile subscriptions not active on the peak day: 6.6 %

People with an active mobile phone of their own, per 100 villagers, if this share of them holds two SIMs
    0 % with two SIMs: 56.0
   20 % with two SIMs: 46.7
   40 % with two SIMs: 40.0
A shared family phone works the other way: one subscription, several users.

Recorded with Python 3.14.8 on macOS 26 arm64. To run it yourself: mise exec python@3.14.8 -- python3 india_constraints.py

Cities have 155.7 subscriptions per 100 people and villages 61.5, a gap of 2.5 times, and 6.6 % of mobile subscriptions were not active on the peak day. If a fifth of rural owners hold two SIMs, about 47 villagers in 100 have an active phone of their own. That share is an assumption, to replace with a survey of your users, but the lesson holds at any value in the program: in a village, design for a shared or basic phone first. The tele-density: Telephone subscriptions per 100 people, as India's telecom regulator TRAI computes it on its own population base. It counts connections rather than people, so it can pass 100. TRAI reports, 61.12 % for rural areas, is the same count on its own population base.

Checkpoint

Check: The four constraints that change a design · Sizing a constraint with official data

Question 1 of 3 You are designing a crop-insurance claim flow for farmers in villages. Which question do you answer before any screen?
Choose one answer.

How many screens the competitor's app has Which phone the farmers use, whether it is shared, and whether they can read the screens Which features to add after launch Which colours the brand uses

Show the answer: Question 1 of 3

Answer: Which phone the farmers use, whether it is shared, and whether they can read the screens

Start from the four constraints, device, network, language and payment, then the smaller questions: who else uses the phone, the cost of data, storage, and who helps when something goes wrong.
Question 2 of 3 What does one of TRAI's telephone subscriptions count?
Choose one answer.

A person who owns a phone A household with a phone A smartphone A connection, so one person with two SIMs counts twice

Show the answer: Question 2 of 3

Answer: A connection, so one person with two SIMs counts twice

Cities count 155.7 subscriptions per 100 people, more than one per person, because some people hold two SIMs. A shared family phone pulls the other way: one subscription, several users.
Question 3 of 3 How many telephone subscriptions per 100 rural people does the program print?
Type a number.
Your answer per 100 people

A hint

Read the rural line of the program's first table.

Show the answer: Question 3 of 3

Answer: 61.5 per 100 people (anything from 61.45 to 61.55 counts)

558.43 million rural subscriptions over 908.2 million rural people of the projection gives 61.5 per 100, against 155.7 in cities: a gap of 2.5 times.

Choose the channel from the group’s constraints

Each channel copes with the constraints differently. An app does the most and asks the most: a smartphone, data and reading. A voice menu works on any phone without data or reading. A missed call costs the caller nothing and gets a call back or a text. Assisted use puts a trusted person between the user and the device. Answer the questions for the group you design for:

Interactive · answer and compare Which channel fits your user group? Answer four questions about the people you design for. The table marks the channels that fit and says why the others do not.

Answer the questions above: the table then marks what fits your case and says why the rest does not.

Four channels against the device, the network, reading, trust and the cost to run
Channel	Device	Network	Reading	Trust	Cost to run
Smartphone app How it works: an installed app on the user's own phone	Poor needs a smartphone with room for the install	Mixed needs data at least to sync; an offline mode helps	Mixed icons and voice help, but most screens need reading	Mixed no person to ask when something goes wrong	Good cheapest per user once installed
Voice menu How it works: a call to a number, with spoken menus and keys or speech	Good any phone that can make a call	Good a voice call, no mobile data	Good spoken menus in the caller's language	Mixed a known number helps; a recorded voice is not a person	Mixed paid by the minute of each call
Missed call How it works: a call that is cut at once, answered by a call back or a text	Good any phone; the caller hangs up before paying	Good no data; the answer comes as a call back or a text	Mixed a text reply needs reading; a call back does not	Mixed works when the number is posted where people already are	Good one call back or one text per request
Assisted use How it works: a trusted helper, such as a shopkeeper, uses a device for the user	Good the helper's device, not the user's	Good the helper's connection	Good the helper reads and explains	Good a person the user already knows	Poor a helper's time for every user; the hardest to grow

How the answers decide

“Which phone do most people in the group use?” A basic phone: rules out Smartphone app. Most basic phones run no store apps, while a call, a missed call or a helper works on any phone.
“Which phone do most people in the group use?” A phone shared in the family: adds a caveat to Smartphone app and Missed call. On a shared phone, others see its notifications and texts, and a sign-in must not expose one person's data to another.
“Is mobile data reliable and affordable for them?” Patchy, or costly: adds a caveat to Smartphone app. An app must work offline and send little data when the connection is patchy or costly.
“Can most of them read the language your screens and messages use?” Many cannot: rules out Smartphone app and adds a caveat to Missed call. Screens need reading; a missed call still works if the answer comes as a spoken call back, not a text.
“Is there someone they already trust nearby, such as a shopkeeper or a health worker?” No: rules out Assisted use. Assisted use needs a trusted helper near the user, and this group has none.
“Is there someone they already trust nearby, such as a shopkeeper or a health worker?” Yes: adds a caveat to Assisted use. A helper builds trust fastest, but each one serves only so many people, so plan how the group moves to a channel of its own.

In short: basic phones and low reading rule the app out, a trusted helper nearby makes assisted use the fastest start, and a missed call or a voice menu reaches the most people for the least effort.

Key idea

Choose the channel from the group’s device, network, reading and trust, measured or estimated from official data, before you design a single screen.

Practise: choose a channel for three groups

Make the first decision for three invented groups. Each choice says why it is right or what it misses.

Then answer the self-check below; it asks next about whichever idea above you have shown least.

Two complete designs for users in India, as plans Pro: opens with a Pro, Premium or Ultimate pass

Two invented briefs, answered end to end at the depth of a mid-level answer: payment slips for dairy farmers, and bookings for women who run beauty services from home. Each plan fits on one table.

In this part:

Milk payments for dairy farmers, by voice call and missed call
Bookings for women who run beauty services from home
What the two plans share

1 diagram · about 6 minutes

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It also opens every other in-depth part in Learn and every Pro tool. Sales are final, except where the law gives you a right to withdraw, for example in the EU and the UK (refund policy).

Choosing a channel with the official numbers Pro: opens with a Pro, Premium or Ultimate pass

The channel choice worked through for the same two groups, with the regulator’s counts and each group’s own assumptions in one program you can change and run.

In this part:

How many of 10,000 adults each channel reaches
Which assumption decides, and what would change the choice
Replacing the assumptions with evidence within a week

1 runnable example (Python) · about 4 minutes

Opening this part with your pass…

This part opens with any MySmartCoPilot pass.

Pro pass · 1 week₹79$2.99
30 days₹179$5.99
1 year₹1,699$45

One payment; a pass never renews. The price shown is the total you pay: no fees or charges are added at checkout.

Choose a pass I have a licence key

It also opens every other in-depth part in Learn and every Pro tool. Sales are final, except where the law gives you a right to withdraw, for example in the EU and the UK (refund policy).

Interview questions

Mid to senior

Design appointment reminders for outpatients of a district hospital, where many patients share a basic phone. Which channel do you choose, and why?

Model answer, Pro. Model answers open with any pass; prices are in the notice on this page. First step and follow-ups
Mid to staff

Design a product that helps handloom weavers sell outside their town. What do you assume about their phones, languages and payments, and how do you check those assumptions?

Model answer, Pro. First step and follow-ups
Mid to senior

Many users of your bank's app share one phone with family members. What changes in sign-in, notifications and privacy, and how do you test those changes with real users?

Model answer, Pro. First step and follow-ups

Flashcards · 6 cards

Recall it, then check

Say the answer to yourself before you look: recalling it is what makes it stick.

Which four constraints change a product design for users in India?

Device (a basic or a smart phone, shared or owned), network (whether data is steady and affordable), language (which script people read and type, or whether they speak instead) and payment (which ways to pay work on their phone). Anchor each one with an official figure.
Why is a count of telephone subscriptions not a count of users?

A subscription is a connection: one person may hold two SIMs, a family may share one phone, and some connections are not active (6.6 % on the peak day). Turn the counts into estimates per person and label the assumptions you add.
How do urban and rural telephone subscriptions per 100 people compare in India's regulator data?

About 155.7 in cities against 61.5 in villages, a gap of 2.5 times. If a fifth of rural owners hold two SIMs, only about 47 villagers in 100 have an active phone of their own, so a village design starts from a shared or basic phone.
How can someone with a basic phone pay by UPI?

Through UPI123Pay's four routes: an app on the basic phone, a missed call, a voice menu (IVR) and sound-based payments between phones that are close together. The central bank put feature-phone subscribers at more than 40 crore.
What does each channel need from a user: an app, a voice menu, a missed call or assisted use?

An app needs a smartphone, data and reading. A voice menu works on any phone without data or reading. A missed call costs the caller nothing and brings a call back or a text. Assisted use needs a trusted person, such as a family member or a shopkeeper.
When should you choose the channel in a design for users in India?

Before designing any screen: choose it from the group's device, network, reading and trust, measured or estimated from official data. Basic phones and little reading rule the app out.

Key takeaways

Device, network, language and payment are the four constraints that change a design for Indian users, and each has an official figure to anchor it.
Subscriptions count connections, not people: per 100 people, cities have 155.7 and villages 61.5, and two SIMs or a shared phone move the number of users either way.
The channel follows the group: an app needs a smartphone, data and reading; a voice menu or a missed call needs only a phone; assisted use needs a trusted helper.

Terms in this lesson

tele-density: Telephone subscriptions per 100 people, as India's telecom regulator TRAI computes it on its own population base. It counts connections rather than people, so it can pass 100.

References

Highlights of Telecom Subscription Data (Press Release No. 125) (Telecom Regulatory Authority of India)
Telecom subscription reports (Telecom Regulatory Authority of India)
Report of the Technical Group on Population Projections for India and States 2011–2036 (National Commission on Population, Ministry of Health and Family Welfare)
Reserve Bank of India launches UPI for feature phones (UPI123Pay) and a helpline for digital payments (DigiSaathi) (Reserve Bank of India)
Languages included in the Eighth Schedule of the Indian Constitution (Department of Official Language, Ministry of Home Affairs)
Guidelines for Indian Government Websites and Apps (GIGW 3.0) (National Informatics Centre, Ministry of Electronics and Information Technology)

Report a problem with this lesson

In this module: Product sense and product design

Users, needs and pain points Free lesson, Pro answers: 20 minutes
Designing a product for a user group Free core, Pro depth: 5 of 15 minutes free
Improving an existing product Free core, Pro depth: 7 of 20 minutes free
Critiquing a product you use Free core, Pro depth: 6 of 15 minutes free
Designing products for users in India Free core, Pro depth: 6 of 15 minutes free
Accessibility, privacy and dark patterns Free core, Pro depth: 6 of 15 minutes free
Designing AI product features Free core, Pro depth: 8 of 20 minutes free

What you will learn

Before you start

What you will learn

Before you start

Four constraints change the design: device, network, language and payment

Size a constraint with the official numbers, not a guess

Choose the channel from the group’s constraints

Practise: choose a channel for three groups

Two complete designs for users in India, as plans Pro: opens with a Pro, Premium or Ultimate pass

Choosing a channel with the official numbers Pro: opens with a Pro, Premium or Ultimate pass

Interview questions

Design appointment reminders for outpatients of a district hospital, where many patients share a basic phone. Which channel do you choose, and why?

Design a product that helps handloom weavers sell outside their town. What do you assume about their phones, languages and payments, and how do you check those assumptions?

Many users of your bank's app share one phone with family members. What changes in sign-in, notifications and privacy, and how do you test those changes with real users?

Key takeaways

References