How to build an app like Cash App: features, compliance, and cost

Most people think Cash App is a simple money-sending app. Open it, type a number, hit send. How hard can that be?

Here is what they do not see: a money transmitter compliance layer, KYC identity checks on every user, PCI DSS card data handling, Regulation E consumer protections, Bank Secrecy Act reporting, and a debit card network backed by Sutton Bank. Cash App has 56 million monthly active users. The reason it works is not the clean UI. It is the regulatory infrastructure underneath.

If you want to build something like it, you need to understand what "it" actually is — and where the real complexity lives.

What Cash App actually is

Cash App is not one product. It is four products sharing a single app.

P2P payments: Send and receive money by phone number, $Cashtag, or QR code. Instant transfers between Cash App users. Free for standard bank deposits (1-3 days), 1.5% fee for instant transfers.

Cash Card: A Visa debit card linked to the user's Cash App balance. Works anywhere Visa is accepted. No monthly fees. Boosts (instant discounts at specific merchants) drive engagement.

Investing: Stocks and Bitcoin available directly in the app. Fractional shares starting at $1. Bitcoin buying, selling, and withdrawals to external wallets.

Direct deposit: Users can route their paycheck to their Cash App account. The account earns interest (when enabled) and supports early direct deposit (up to two days early).

Most founders who say they want to "build Cash App" actually want to build the P2P payments piece. That is fine. But be clear about which product you are building — the compliance requirements, development cost, and time to market are completely different for each.

Core P2P payment features

If you are building the P2P payments layer, here is what you need for an MVP.

That list looks manageable. It is — until you try to actually move money.

The QR code and $Cashtag experience

Cash App's $Cashtag is a unique username that makes sending money feel as easy as texting. Each user picks a handle ($YourName) and shares it like a social profile. QR codes tie to the same identifier and let in-person payments happen in seconds.

Building this is straightforward. A unique username table, QR code generation, and a lookup at send time. The hard part is not the QR code. The hard part is what happens when you press send.

What actually happens when money moves

When a Cash App user sends $50, here is what happens behind the scenes:

1. Your app checks the sender's identity (KYC verified? Not on a sanctions list?)
2. The transaction is screened for fraud signals
3. If the transfer is above certain thresholds, AML rules trigger review
4. Money moves from the sender's balance or linked bank account
5. The recipient's balance updates instantly (for Cash App user-to-user)
6. If the recipient wants the money in their bank, an ACH transfer initiates

None of that is a standard CRUD app. Each step touches a regulated financial workflow.

The compliance wall

This is what makes fintech harder than other app types. Not the features. The rules.

Money transmitter license (or a licensed partner)

In the US, moving money for other people is a regulated activity. You need a money transmitter license (MTL) in every state where you operate — 49 states have separate licensing requirements. Getting licensed in all 49 states takes 18-36 months and costs $200,000-$500,000 in fees, legal work, and bonding requirements.

The shortcut: do not get your own license. Use Stripe, Dwolla, or a similar licensed processor. They hold the MTL. You build on their API. You become a service that uses a money transmitter, not a money transmitter yourself.

This is how most fintech startups work. Stripe Payments handles the money movement. Dwolla handles ACH. You handle the user experience and business logic.

KYC and AML

Know Your Customer (KYC) means verifying that your users are who they say they are. Anti-Money Laundering (AML) means monitoring transactions for patterns that suggest money laundering.

For a P2P app, KYC means:

• Collecting name, date of birth, address, and SSN (or last 4 digits for lower limits)

• Verifying government-issued ID (driver's license, passport)

• Running against OFAC sanctions lists and politically exposed persons (PEP) databases

• Ongoing monitoring as users transact

You do not build this yourself. Use Onfido, Persona, Socure, or Stripe Identity. These services run $0.50-$3.00 per verification and handle the document analysis, liveness checks, and sanctions screening. They also provide audit logs that regulators can examine.

AML monitoring is separate. You need transaction monitoring rules that flag unusual patterns — sudden large transfers, structuring behavior, high-velocity transactions. Services like Unit21 or Sardine handle this for smaller fintechs.

PCI DSS

If your app stores, processes, or transmits card data (for the debit card feature), you need PCI DSS compliance. At the SAQ-A level (using a compliant processor like Stripe), this is mostly paperwork and annual attestation. At higher levels, it requires formal audits by a Qualified Security Assessor.

For P2P-only apps with no card storage, PCI requirements are minimal. The moment you add a virtual or physical debit card, you enter PCI scope.

Regulation E

Reg E requires that you:

• Disclose your error resolution procedures to users

• Investigate and resolve unauthorized transaction claims within specific timeframes (10 business days for investigation, 5 business days for provisional credit)

• Provide transaction receipts and periodic statements

This is not optional. If a user claims they did not authorize a transaction, you have legal obligations on timing and process. Build the dispute workflow before you launch, not after a user complaint.

Bank Secrecy Act (BSA)

The BSA requires that you:

• File Currency Transaction Reports (CTRs) for cash transactions over $10,000

• File Suspicious Activity Reports (SARs) for transactions that appear suspicious

• Maintain transaction records for five years

Most fintechs handle this through their licensed processor (Stripe, Dwolla) or a Banking-as-a-Service platform. But you still need an internal compliance program — someone responsible for BSA compliance, written policies, and employee training.

The shortcut: Build on top of a licensed processor

The fastest and cheapest path to a compliant P2P payments app is to use existing infrastructure for the regulated parts.

Stripe: The most common choice. Stripe Payments handles money movement. Stripe Connect handles marketplace-style flows where multiple parties send and receive. Stripe Identity handles KYC. Together, they cover most of what a P2P app needs at the payment layer.

Dwolla: Focused on ACH transfers. Better for bank-to-bank flows than card payments. Strong compliance documentation and a clear API. Popular for payroll and B2B payment apps.

Plaid: Not a payment processor — Plaid connects bank accounts. Users link their bank via Plaid, which verifies the account and provides balance information. Essential for funding the wallet and initiating withdrawals.

Onfido / Persona: KYC identity verification. Users upload their ID and take a selfie. The service runs document verification, liveness checks, and sanctions screening. Returns a pass/fail with a confidence score.

Using these services means your app never touches the raw payment rails. You call an API. The licensed provider moves the money. This cuts your compliance burden significantly and gets you to market faster.

Tech stack

• Mobile: React Native (iOS and Android from one codebase)

• Backend: Node.js on AWS

• Database: PostgreSQL (transactions, user accounts, balances)

• Payments: Stripe Connect or Dwolla (ACH, wallet management)

• Bank linking: Plaid (account verification, balance checks)

• KYC: Onfido or Persona (document verification, liveness checks)

• AML monitoring: Unit21 or Sardine (transaction monitoring)

• Fraud: Stripe Radar or a dedicated fraud service

• Notifications: Firebase (push), Twilio (SMS)

• Infrastructure: AWS (EC2, RDS, SQS for async payment processing)

One critical point on infrastructure: payment processing must be asynchronous. ACH transfers take 1-3 business days. Your app needs a queue-based architecture (SQS or similar) that handles payment state updates without blocking the user experience. This is not how most non-fintech apps are built.

Cost breakdown

To model team cost: a 3-person team (1 senior engineer + PM + QA) at $18,000-$22,500/month delivers an MVP in 16-24 weeks. Add a compliance specialist ($5,000-$10,000/month) during setup. These are RaftLabs internal rates from our cost model.

The real question: what are you building?

Before scoping a fintech project, answer this question honestly.

Option A: A P2P payments feature

You want to add money-sending to an existing product or build a standalone P2P app. This is the simplest path. Use Stripe + Plaid + Onfido. Build on licensed infrastructure. Your compliance burden is manageable. Budget $60,000-$120,000 and 16-24 weeks.

Option B: A neobank

You want accounts, debit cards, direct deposit, and savings features. This is what Cash App has become. You need a Banking-as-a-Service partner (Column, Unit, Synctera, or Piermont Bank) to issue accounts and cards. The BaaS partner holds the bank charter. You provide the front end. Budget $250,000-$600,000 and 36-60 weeks. Ongoing compliance is significantly more complex.

Option C: Payments infrastructure

You want to be the infrastructure layer — processing payments for other businesses. This is the Stripe model. This requires your own money transmitter licenses, significant capital reserves, and years of regulatory work. This is not a startup project. Do not attempt this without a $5M+ runway and a dedicated compliance team.

Most founders want Option A but describe Option B when they say "Cash App." Get clear on which one you are building. The gap in cost and timeline between them is 3-5x.

What RaftLabs would build

For a founder entering P2P payments, here is our honest recommendation:

Start with an MVP that covers the core send/receive flow, Plaid bank linking, Stripe payment rails, and Onfido KYC. Ship in 16-20 weeks. Get real users transacting. Then decide whether to add cards and investing based on what users actually ask for.

We have built payment platforms, KYC flows, and banking integrations across 100+ shipped products. The fintech projects that go wrong are not the ones that underinvested in features — they are the ones that underinvested in compliance architecture and had to rebuild six months later.

If you are serious about building in this space, talk to our team. We will scope the compliance layer honestly alongside the product, so you know the real cost before you start — not after.

Looking to understand the broader build decision? See custom software development services and our mobile app development cost guide.