Why Some Online Services Require a Phone Number (2026 Guide)

Not long ago, creating an online account required only an email address and a password.

Whether you were signing up for an online forum, an e-commerce website, or a social media platform, the process was usually quick and anonymous. Phone numbers were rarely requested, and many users completed registration without ever sharing additional personal information.

Today, the situation looks very different.

Open almost any modern online service, and there is a good chance you will be asked to provide a mobile phone number.

Sometimes it is required during registration.

Sometimes it becomes mandatory only when enabling additional security features.

In other cases, websites request a phone number before allowing users to recover an account, publish content, make financial transactions, or verify their identity.

For many people, this raises an obvious question:

Why do so many online services require a phone number?

At first glance, the answer seems simple.

Most users assume companies need the number only to send verification codes.

While that is certainly one reason, it is far from the complete explanation.

In reality, the modern phone number has become one of the most valuable identity signals available on the internet.

Unlike an email address, creating a phone number usually requires interaction with a mobile network operator. Unlike usernames, phone numbers are relatively expensive to obtain at scale. Unlike passwords, they are linked to an external communications infrastructure that websites themselves do not control.

These characteristics make phone numbers useful for much more than sending SMS messages.

Today they help online services:

reduce automated fraud;
prevent large-scale spam;
verify that accounts belong to real people;
recover access after forgotten passwords;
detect suspicious login attempts;
protect financial transactions;
improve trust between users;
strengthen overall account security.

This explains why two websites offering similar services may have completely different registration requirements.

One platform may allow immediate access with nothing more than an email address.

Another may insist on phone verification before the account can perform even basic actions.

The difference is rarely arbitrary.

It usually reflects the type of risks that each service must manage.

A discussion forum faces different threats than a cryptocurrency exchange.

An online game encounters different abuse patterns than a digital banking application.

As a result, every platform develops its own balance between convenience, privacy, and security.

Understanding this balance helps explain why phone verification has become increasingly common despite growing concerns about personal privacy.

It also helps answer another important question.

If some websites require phone numbers while others do not, what determines that decision?

The answer lies in the role that phone numbers now play within modern digital identity systems.

Throughout this guide, we will examine how online services use phone numbers, why they continue relying on them even as new authentication technologies emerge, and why simply viewing a phone number as a way to receive SMS messages no longer reflects how the modern internet operates.

By the end of this article, you will understand:

why companies request phone numbers during registration;
how phone numbers help reduce fraud;
why they remain important for account recovery;
how businesses balance privacy and security;
why some websites never ask for a number at all;
and what users should consider before deciding whether to provide one.

A Phone Number Is No Longer Just Contact Information

One of the biggest changes in online security over the past decade is the role that phone numbers play.

Originally, a mobile number served one primary purpose.

It allowed people to communicate.

Voice calls and text messages were the main functions associated with mobile subscriptions, and websites rarely viewed phone numbers as anything more than optional contact details.

Today, that perspective has changed completely.

For many online services, a phone number has become one of the strongest indicators that an account belongs to a real individual rather than an automated system.

Unlike usernames, phone numbers cannot usually be generated instantly in unlimited quantities.

Unlike disposable email addresses, obtaining and maintaining mobile numbers generally involves greater cost, infrastructure, and verification.

These characteristics make phone numbers valuable signals for identity verification.

Importantly, companies are rarely interested in the number itself.

What matters is what the number represents.

It indicates that a user has access to a communication channel that can be used when additional confirmation becomes necessary.

This distinction explains why phone numbers appear throughout the entire lifecycle of an account rather than only during registration.

A number may later be used to:

confirm unusual login attempts;
verify changes to security settings;
approve sensitive financial actions;
recover access after a forgotten password;
detect suspicious account behavior;
confirm ownership after long periods of inactivity.

In other words, the phone number gradually becomes part of the account's identity rather than remaining simple contact information.

Why Companies Trust Phone Numbers More Than Email Addresses

Many users ask another reasonable question.

"If websites already have my email address, why do they also need my phone number?"

The answer lies in the differences between the two identifiers.

Creating an email account is extremely easy.

A single individual can create dozens—or even hundreds—of email addresses within a short period of time.

Automated systems can generate large numbers of accounts with relatively little effort.

For legitimate users, this flexibility is convenient.

For online platforms trying to fight abuse, however, it creates challenges.

Phone numbers are different.

Although obtaining additional numbers is certainly possible, doing so usually requires more time, greater expense, and interaction with mobile operators or telecommunications services.

This higher barrier increases the cost of operating fake accounts at scale.

For businesses that constantly battle spam, automated registrations, fake reviews, and fraudulent activity, even a small increase in attacker costs can significantly reduce abuse.

That is one reason phone verification remains popular across many industries despite the emergence of newer authentication technologies.

Identity Verification Starts With Trust

When a company asks for your phone number, it is rarely trying to prove exactly who you are.

Instead, it is attempting to increase confidence that the account belongs to a genuine person who can be contacted if necessary.

This concept is often misunderstood.

Phone verification does not function like a passport or national identity document.

It does not reveal your full identity.

Instead, it provides evidence that the person creating or accessing the account controls a working communication channel.

This additional signal helps platforms make better security decisions.

For example, an account that has existed for several years, consistently signs in from familiar devices, and successfully verifies activity using the same trusted phone number is generally considered less risky than a newly created account with no established history.

As more trustworthy signals accumulate over time, online services can gradually reduce unnecessary friction while remaining alert to suspicious activity.

Understanding how websites actually deliver verification messages—and why SMS continues to play such an important role in that process—becomes much easier after reading ➡️ How SMS Verification Works, where we explain the complete journey of an authentication message from the website to your mobile device.

Trust Is Built Over Time

One important detail is often overlooked.

A phone number does not become valuable simply because it exists.

Its value grows over time.

A number that remains associated with the same account for several years provides a much stronger trust signal than one that changes every few weeks.

This is one reason many platforms ask users to confirm phone number changes before updating security settings.

Frequent changes may indicate perfectly legitimate circumstances, but they can also resemble patterns associated with fraudulent activity.

By combining phone verification with other signals such as login history, trusted devices, and behavioral analysis, online services can distinguish ordinary account maintenance from activity that deserves closer examination.

Rather than relying on any single factor, modern identity systems evaluate many pieces of information together to make more accurate security decisions.

Why Phone Numbers Help Prevent Fraud

Every online platform faces the same fundamental challenge.

How can it distinguish between a genuine customer and someone attempting to abuse the service?

The answer is rarely based on a single piece of information.

Instead, modern platforms evaluate dozens—or even hundreds—of signals before deciding whether an account appears trustworthy.

Among these signals, a verified phone number continues to play an important role.

This does not mean that every user with a phone number is trustworthy.

Nor does it mean that accounts without phone verification are automatically suspicious.

Rather, a verified number provides one additional piece of evidence that helps the platform assess risk.

For companies operating at massive scale, even small improvements in risk assessment can prevent millions of fraudulent registrations each year.

Fake Accounts Are Expensive

Many people underestimate the scale of automated abuse on the internet.

Every day, online services face enormous numbers of:

fake registrations;
automated bots;
spam campaigns;
fraudulent promotions;
phishing attempts;
fake reviews;
mass account creation.

Most of these activities rely on creating large numbers of accounts quickly and cheaply.

From the attacker's perspective, the lower the cost of creating an account, the more profitable large-scale abuse becomes.

Phone verification changes this equation.

Even though obtaining phone numbers is possible, it usually requires more effort, higher costs, or interaction with telecommunications infrastructure than generating disposable email addresses.

As a result, requiring phone verification raises the cost of abuse.

For legitimate users, verifying a phone number usually takes less than a minute.

For attackers attempting to create thousands of accounts automatically, repeating that process at scale becomes significantly more difficult and expensive.

This difference is one of the main reasons why so many online platforms continue requesting phone numbers during registration.

Fighting Bots Instead of People

Another common misunderstanding is that websites request phone numbers because they do not trust their users.

In reality, the primary target is often automation, not people.

Modern bots have become remarkably sophisticated.

They can solve simple registration forms, generate realistic usernames, rotate IP addresses, and even imitate human browsing behavior.

For many years, CAPTCHAs were considered the primary defense against this type of abuse.

While they remain useful, automated systems have become increasingly effective at bypassing traditional CAPTCHA challenges.

Phone verification introduces a different type of obstacle.

Instead of asking whether the visitor can recognize images or solve a puzzle, the platform asks whether they can successfully complete verification using a mobile number.

For automated systems attempting to create thousands of accounts simultaneously, this additional requirement substantially increases operational complexity.

The objective is not to make registration impossible.

It is to make abuse economically unattractive.

Why Phone Numbers Reduce Spam

Spam is not limited to email.

Almost every online platform experiences some form of unwanted activity.

Examples include:

fake product reviews;
misleading advertisements;
fraudulent marketplace listings;
abusive comments;
mass messaging campaigns;
coordinated manipulation;
promotional scams.

Many of these activities depend on creating large numbers of disposable accounts.

If each new account requires nothing more than an email address, abusive users can often replace blocked accounts within minutes.

Introducing phone verification slows this process.

Each verified account becomes slightly more expensive to create.

More importantly, platforms gain an additional identifier that helps recognize repeated abuse patterns.

Although no security measure completely eliminates spam, combining phone verification with behavioral analysis significantly improves detection.

Building Trust Between Users

Phone verification is not only about protecting the platform.

It also affects how users interact with one another.

Consider services where people exchange money, purchase goods, rent accommodation, or hire freelancers.

Trust becomes one of the most valuable assets.

When users know that every account has completed at least some level of identity verification, they often feel more comfortable interacting with strangers.

The phone number itself does not guarantee honesty.

However, it raises the perceived cost of creating fraudulent identities and therefore contributes to a healthier online ecosystem.

This is one reason why marketplaces, financial platforms, and peer-to-peer services frequently encourage or require phone verification.

Risk Scoring: Why Companies Evaluate More Than One Signal

One of the biggest misconceptions about online security is that websites make decisions using a single rule.

For example:

"The phone number is verified, therefore the account is trusted."

Modern platforms rarely work this way.

Instead, they use what security professionals often call risk scoring or risk-based authentication.

Rather than evaluating only one factor, the platform combines many different signals before deciding whether additional verification is necessary.

These signals may include:

phone verification;
email reputation;
device history;
browser fingerprint;
IP address reputation;
geographic location;
login frequency;
typing behavior;
account age;
previous successful logins.

Each individual signal tells only part of the story.

Together, they help build a much clearer picture of whether current activity appears normal or unusual.

For example, imagine that you sign in from the same laptop you have used for several years, from your usual city, with the same browser, during your normal working hours.

Even if the platform requests an SMS verification code, the overall risk score remains relatively low because everything else looks familiar.

Now imagine the opposite scenario.

The account is accessed from a new country using an unfamiliar device and an unknown network immediately after a password reset request.

Even if the correct phone number is available, the platform may require additional verification before granting access.

This illustrates an important principle.

A phone number is valuable—but it is only one element within a much larger security system.

Readers interested in understanding why websites send one-time verification messages as part of these workflows can continue with ➡️ What Is an OTP Code?, which explains how temporary authentication codes fit into modern account security.

Why Businesses Continue Using SMS Despite New Technologies

Over the past few years, new authentication methods have become increasingly popular.

Passkeys.

Authenticator applications.

Hardware security keys.

Biometric authentication.

All of these technologies provide significant security advantages.

Yet SMS verification remains one of the most widely used authentication methods in the world.

Why?

The answer is accessibility.

Almost every internet user already has access to a mobile phone capable of receiving text messages.

No additional application needs to be installed.

No special hardware is required.

No technical knowledge is necessary.

From the perspective of a business serving millions of customers across different countries and devices, SMS remains one of the few authentication methods that works almost everywhere.

That does not mean it is perfect.

It simply means it offers a practical balance between security, convenience, cost, and global compatibility.

For this reason, many organizations no longer view SMS as their only authentication method.

Instead, they treat it as one layer within a broader identity verification strategy.

Why Some Websites Do Not Require a Phone Number

After learning why so many online services request phone verification, another question naturally follows:

If phone numbers are so useful, why do some websites never ask for one?

The answer lies in the different goals of different platforms.

Not every service faces the same security challenges.

A website that publishes news articles has very different risks than an online bank.

An educational blog does not require the same level of identity verification as a cryptocurrency exchange.

Likewise, a simple weather application does not need the same fraud prevention systems as an online marketplace where users exchange money.

Because of these differences, every organization makes its own decision about the balance between convenience, privacy, and security.

For some businesses, requesting a phone number would introduce unnecessary friction without providing meaningful benefits.

For others, it has become an essential part of protecting both the company and its users.

Low-Risk Services

Many websites intentionally avoid collecting phone numbers because they simply do not need them.

Examples include:

informational websites;
online documentation;
blogs;
recipe websites;
public knowledge bases;
software documentation;
online calculators.

These services rarely require long-term user identity.

In many cases, users can browse anonymously without creating an account at all.

Even when registration is available, email verification is often sufficient because the consequences of account abuse are relatively limited.

If an attacker creates a fake account on a recipe website, the impact is usually minimal.

The platform therefore has little incentive to increase registration friction by requesting phone verification.

Services That Prioritize User Privacy

Some organizations deliberately minimize the amount of personal information they collect.

Their philosophy is based on a simple principle:

If data is never collected, it cannot be stolen, leaked, or misused.

Privacy-focused companies often attempt to reduce the amount of personally identifiable information stored within their systems.

Depending on the service, this may include avoiding:

phone numbers;
full names;
physical addresses;
dates of birth;
unnecessary profile information.

Instead, they rely on alternative authentication methods such as email verification, passkeys, or authentication applications.

For users who value anonymity, these platforms may provide a better balance between convenience and privacy.

The Cost of Additional Friction

Every extra field added to a registration form reduces the number of people who successfully complete it.

This is one of the oldest principles in user experience design.

If registration requires only:

an email address;
a password;
acceptance of the terms,

many visitors will complete the process in less than a minute.

Adding a phone number introduces additional steps.

The user must:

enter the number;
wait for an SMS;
receive the code;
enter the verification code correctly.

Although this process is relatively simple, every additional action causes a small percentage of users to abandon registration.

Businesses constantly evaluate this trade-off.

Higher security usually means more verification.

More verification usually means lower conversion rates.

The ideal balance depends entirely on the purpose of the platform.

Privacy Concerns: Why Some Users Prefer Not to Share Their Phone Number

From the user's perspective, hesitation is understandable.

A phone number often feels more personal than an email address.

People worry about:

unwanted marketing;
spam messages;
telemarketing calls;
data breaches;
identity theft;
excessive tracking.

These concerns are not unreasonable.

Phone numbers are long-term identifiers that frequently remain unchanged for years.

Unlike passwords, they cannot simply be invented at random.

Unlike usernames, they are connected to real-world telecommunications infrastructure.

Because of this, many users prefer to disclose them only when absolutely necessary.

Responsible companies recognize these concerns and increasingly explain why phone verification is required before requesting a number.

Transparency helps users make informed decisions instead of feeling that unnecessary personal information is being collected.

Can You Refuse to Provide Your Phone Number?

Sometimes.

The answer depends entirely on the service.

Many platforms treat phone verification as optional.

Users can create an account using only an email address but may later encounter restrictions.

For example, certain features might remain unavailable until the phone number has been verified.

Other services make phone verification mandatory from the beginning.

This is especially common for:

financial institutions;
payment platforms;
cryptocurrency exchanges;
marketplaces;
ride-sharing applications;
messaging services.

In these cases, refusing to provide a phone number usually means the account cannot be created or certain functions remain inaccessible.

Ultimately, every company determines its own security requirements based on the risks associated with its service.

Choosing the Right Verification Method

Although this article focuses on why companies request phone numbers, users often ask a different question:

If a service requires phone verification, what should I consider before choosing how to receive those verification messages?

The answer depends on your intended use.

Some users need verification only once.

Others manage multiple online accounts.

Businesses may require scalable verification workflows.

Developers often need temporary numbers for testing environments.

Understanding these different scenarios helps explain why multiple verification options exist.

Readers interested in comparing different approaches can continue with ➡️ How to Choose an SMS Verification Service, where we discuss the factors that matter most when selecting a verification solution for different use cases.

When SMS Is Not Available

Phone verification is valuable only if verification messages can actually reach you.

Most of the time this happens automatically.

Occasionally, however, users encounter situations where SMS messages cannot be received immediately.

This may happen because of:

temporary network problems;
international travel;
damaged SIM cards;
device migration;
mobile operator issues.

These situations do not necessarily mean your account has become inaccessible.

Understanding how SMS delivery depends on your mobile subscription and device configuration helps reduce unnecessary concern.

If you are currently unable to receive verification messages, ➡️ Can You Receive SMS Without a SIM Card? explains which scenarios still allow SMS reception and which require alternative recovery methods.

Frequently Asked Questions

Why do websites ask for my phone number instead of just my email?

Email addresses are easy to create in large numbers.

Phone numbers generally require access to mobile telecommunications infrastructure, making them more useful as one of several trust signals.

Most modern platforms combine both identifiers rather than relying exclusively on one.

Does giving a website my phone number mean it knows my identity?

Not necessarily.

A verified phone number confirms access to a working communication channel.

It does not automatically reveal your full identity.

Many services use the number as one factor among many when evaluating account security.

Why do banks almost always require phone verification?

Financial institutions face significantly higher fraud risks than most websites.

Phone verification helps confirm important actions, notify customers about suspicious activity, and strengthen account recovery procedures.

Can I create an account without providing my phone number?

Sometimes.

Many services allow registration using only an email address.

Others require phone verification before certain features become available or before the account can be created at all.

The decision depends on the security requirements of each platform.

Will websites continue using SMS in the future?

Probably—but alongside newer technologies.

Passkeys, authenticator applications, and hardware security keys continue growing in popularity.

However, SMS remains one of the most widely supported authentication methods worldwide because of its accessibility and compatibility across devices and countries.

Final Thoughts

The question is no longer simply why websites ask for phone numbers.

The more important question is what role phone numbers play in modern digital identity.

Over the past decade, mobile numbers have evolved far beyond their original purpose.

They are no longer used only for voice calls or text messages.

Today they help protect accounts, reduce fraud, prevent spam, support account recovery, and strengthen trust between users and online services.

At the same time, no responsible security system should depend entirely on a single identifier.

The strongest platforms combine phone verification with many other signals, including trusted devices, email verification, behavioral analysis, authentication applications, and modern passwordless technologies.

For users, understanding this broader picture makes registration requests easier to interpret.

A company requesting a phone number is not necessarily attempting to collect unnecessary personal information.

In many cases, it is balancing convenience, security, fraud prevention, and user trust within a much larger authentication system.

As online identity continues evolving, phone numbers will likely remain an important part of that system.

Their role may gradually change alongside passkeys and other modern authentication methods, but for the foreseeable future they will continue serving as one of the internet's most widely recognized trust signals.

Readers who would like a broader understanding of how SMS verification fits into today's authentication ecosystem can continue with ➡️ How to Receive SMS Online, which serves as the central guide for this entire topic cluster.

Why Some Websites Do Not Require a Phone Number

After learning why so many online services request phone verification, another question naturally follows:

If phone numbers are so useful, why do some websites never ask for one?

The answer lies in the different goals of different platforms.

Not every service faces the same security challenges.

A website that publishes news articles has very different risks than an online bank.

An educational blog does not require the same level of identity verification as a cryptocurrency exchange.

Likewise, a simple weather application does not need the same fraud prevention systems as an online marketplace where users exchange money.

Because of these differences, every organization makes its own decision about the balance between convenience, privacy, and security.

For some businesses, requesting a phone number would introduce unnecessary friction without providing meaningful benefits.

For others, it has become an essential part of protecting both the company and its users.

Low-Risk Services

Many websites intentionally avoid collecting phone numbers because they simply do not need them.

Examples include:

informational websites;
online documentation;
blogs;
recipe websites;
public knowledge bases;
software documentation;
online calculators.

These services rarely require long-term user identity.

In many cases, users can browse anonymously without creating an account at all.

Even when registration is available, email verification is often sufficient because the consequences of account abuse are relatively limited.

If an attacker creates a fake account on a recipe website, the impact is usually minimal.

The platform therefore has little incentive to increase registration friction by requesting phone verification.

Services That Prioritize User Privacy

Some organizations deliberately minimize the amount of personal information they collect.

Their philosophy is based on a simple principle:

If data is never collected, it cannot be stolen, leaked, or misused.

Privacy-focused companies often attempt to reduce the amount of personally identifiable information stored within their systems.

Depending on the service, this may include avoiding:

phone numbers;
full names;
physical addresses;
dates of birth;
unnecessary profile information.

Instead, they rely on alternative authentication methods such as email verification, passkeys, or authentication applications.

For users who value anonymity, these platforms may provide a better balance between convenience and privacy.

The Cost of Additional Friction

Every extra field added to a registration form reduces the number of people who successfully complete it.

This is one of the oldest principles in user experience design.

If registration requires only:

an email address;
a password;
acceptance of the terms,

many visitors will complete the process in less than a minute.

Adding a phone number introduces additional steps.

The user must:

enter the number;
wait for an SMS;
receive the code;
enter the verification code correctly.

Although this process is relatively simple, every additional action causes a small percentage of users to abandon registration.

Businesses constantly evaluate this trade-off.

Higher security usually means more verification.

More verification usually means lower conversion rates.

The ideal balance depends entirely on the purpose of the platform.

Privacy Concerns: Why Some Users Prefer Not to Share Their Phone Number

From the user's perspective, hesitation is understandable.

A phone number often feels more personal than an email address.

People worry about:

unwanted marketing;
spam messages;
telemarketing calls;
data breaches;
identity theft;
excessive tracking.

These concerns are not unreasonable.

Phone numbers are long-term identifiers that frequently remain unchanged for years.

Unlike passwords, they cannot simply be invented at random.

Unlike usernames, they are connected to real-world telecommunications infrastructure.

Because of this, many users prefer to disclose them only when absolutely necessary.

Responsible companies recognize these concerns and increasingly explain why phone verification is required before requesting a number.

Transparency helps users make informed decisions instead of feeling that unnecessary personal information is being collected.

Can You Refuse to Provide Your Phone Number?

Sometimes.

The answer depends entirely on the service.

Many platforms treat phone verification as optional.

Users can create an account using only an email address but may later encounter restrictions.

For example, certain features might remain unavailable until the phone number has been verified.

Other services make phone verification mandatory from the beginning.

This is especially common for:

financial institutions;
payment platforms;
cryptocurrency exchanges;
marketplaces;
ride-sharing applications;
messaging services.

In these cases, refusing to provide a phone number usually means the account cannot be created or certain functions remain inaccessible.

Ultimately, every company determines its own security requirements based on the risks associated with its service.

Choosing the Right Verification Method

Although this article focuses on why companies request phone numbers, users often ask a different question:

If a service requires phone verification, what should I consider before choosing how to receive those verification messages?

The answer depends on your intended use.

Some users need verification only once.

Others manage multiple online accounts.

Businesses may require scalable verification workflows.

Developers often need temporary numbers for testing environments.

Understanding these different scenarios helps explain why multiple verification options exist.

When SMS Is Not Available

Phone verification is valuable only if verification messages can actually reach you.

Most of the time this happens automatically.

Occasionally, however, users encounter situations where SMS messages cannot be received immediately.

This may happen because of:

temporary network problems;
international travel;
damaged SIM cards;
device migration;
mobile operator issues.