How to Build a Trading App Like Robinhood: Cost, Phases, and the Brokerage API Decision

You want to build a commission-free trading app. Maybe you run an investment club that is tired of routing everyone to different brokerage accounts. Maybe you are a fintech company adding equity trading to an existing crypto platform. Maybe your company needs an employee equity portal that does not look like a 2009 enterprise tool. Or you are building a retirement-focused app for a specific community and Robinhood's general-purpose interface does not fit.

In every case, you are asking the same question: how hard is it to build a trading app like Robinhood, and what does it actually cost?

The short answer is $50K-$130K and 14-28 weeks for engineering. The longer answer involves picking the right brokerage API, understanding what the regulatory timeline does to your calendar, and knowing which features to build first versus which ones to save for later.

Here is what you need to know before you start.

Ongoing costs after launch run $8K-$20K per month for market data feeds, clearing firm fees, and compliance tooling. According to FINRA's 2023 Annual Financial Report, there were roughly 3,500 registered broker-dealers in the US at year-end. Most fintech products never become one - they partner with one instead.

Who actually builds a commission-free trading app

Most people asking how to build a trading app like Robinhood are not trying to out-compete Robinhood for the retail mass market. That product is free, brand-entrenched, and backed by billions in capital. The businesses that make economic sense are specific.

Investment clubs and community-run funds need a branded experience where members can view a shared portfolio, see their individual allocations, and execute trades without being pushed to open separate personal brokerage accounts. The product is not a consumer app - it is a closed-loop platform for a defined membership. Revenue comes from subscription fees, not payment for order flow.

Fintech companies with an existing crypto user base want to add US equity trading without rebuilding their entire platform. Their users already have verified accounts, already trust the platform with financial assets, and are already asking for stocks. Adding equity execution via DriveWealth or Alpaca is an expansion play, not a net-new product. The KYC infrastructure already exists; the order management layer is new.

Employee equity portals for pre-IPO companies need to show employees their options grants, vesting schedules, and exercise windows in a clean interface that is not the default cap table software UI. Some of these products eventually add secondary market trading features. All of them need real-time pricing to show employees what their options are worth on any given day.

Retirement-focused investing apps targeting specific communities - diaspora groups, religious communities with specific investment criteria, professionals in a particular field - need a product that reflects their values and restrictions. ESG-only portfolios, halal investment screens, or state-specific retirement savings programs all require a platform you control. Robinhood cannot serve these audiences because its general-purpose interface has no mechanism to restrict the investable universe or enforce community-specific rules.

"The business model of payment for order flow, combined with zero-commission trading, fundamentally changed retail investing. But it created a template that only works at scale. Smaller players need a different revenue model from day one."

• William Birdthistle, Director of the Division of Investment Management, US SEC (remarks to the Practising Law Institute, 2022)

V1/V2/V3 features: what goes in each phase

The failure mode in trading app builds is trying to ship everything at once. Teams scope an MVP that includes fractional shares, options trading, tax-loss harvesting, a social feed, and recurring investments. Six months later, nothing is live. The compliance build took longer than expected and the feature list never got cut.

Phase the build. Here is what belongs where, and what each phase costs.

V1 - launch ($50K-$80K, 20-24 weeks for equity)

These are the features you cannot open the doors without.

Skipping the audit logging is the most common shortcut teams take. FINRA examiners will ask for it. Retrofitting it after launch costs more than building it correctly the first time and takes 6-8 weeks of engineering that could go toward growth features.

V2 - growth ($25K-$45K additional, after proving the model)

These features matter once you have real users and real trading volume. Building them before that is waste.

• Fractional shares let users buy $50 of a $400 stock, opening the product to lower-account-balance users. Cost to add post-launch: $8K-$15K.

• Watchlists and price alerts are the engagement layer that brings users back daily. Cost: $5K-$8K.

• Recurring investments - automated weekly or monthly purchases - are a retention feature with direct impact on AUM. Cost: $7K-$12K.

• Tax documents (1099-B, 1099-DIV) are a year-end requirement for taxable accounts. Your clearing firm handles the calculations; your platform generates the download. Cost: $5K-$8K.

V3 - scale ($50K-$90K additional, only relevant above serious volume)

• Options trading: separate regulatory requirements, more complex order logic, higher customer service burden. Do not add until V2 features are stable. Cost: $20K-$35K.

• Margin accounts: requires additional FINRA compliance work. Margin lending is a revenue line but adds risk management complexity. Cost: $15K-$25K.

• Crypto alongside equities: a separate execution layer with different custody rules. Cost: $18K-$30K.

Off-the-shelf brokerage APIs vs. custom execution: what you need to know about each

This is the most consequential decision in the build. You are not building a trading engine. You are choosing which registered broker-dealer's infrastructure to sit on top of.

DriveWealth is built for international fintech companies and embedded finance products. If you are based outside the US and want to offer US equities to your users, DriveWealth is the standard choice. It handles fractional shares, has a clean REST API, and manages the FINRA compliance layer on your behalf. The failure points: onboarding takes 4-8 weeks and requires a detailed compliance review of your product before they will let you go live. Their revenue share model on order flow is opaque until you are in contract negotiations. And their support documentation lags behind their actual API capabilities, which means edge cases (partial fills on fractional orders, account restriction handling) require direct back-and-forth with their team rather than documentation lookup. Also, DriveWealth's pricing tiers are built for high-volume products - at sub-10,000 users, your per-trade economics are not favorable.

Alpaca is the fastest path to live US equity trading for most new fintech products. The API is genuinely developer-friendly, the documentation is thorough, and the sandbox environment actually reflects production behavior. Fractional share support is built in. No minimum capital requirement to get started. The failure points: Alpaca's customer support is async and slow for non-technical issues (account restriction appeals, KYC edge cases). Their real-time data offering is limited unless you also subscribe to Polygon.io separately, which adds $79-$199/month to your stack. And Alpaca does not offer crypto custody, so if you want a single platform covering both asset classes, you need a second execution partner.

Apex Clearing is where institutional-grade products land. Apex is the clearing firm behind Robinhood itself, plus Webull, Public.com, and dozens of other consumer brokerages. A white-label agreement with Apex gives you access to the same execution infrastructure that powers the biggest names in retail trading. The failure points: getting an Apex agreement requires demonstrating significant capitalization and a credible compliance program upfront. The minimum monthly fees are high enough that sub-$1M products will find the economics unworkable. Their technical integration is also more complex than Alpaca's - Apex uses FIX protocol for order routing, which requires a different kind of engineering than a REST API. Expect 3-4 months of integration work before you are in production.

Interactive Brokers API is for complex, multi-asset institutional products: futures, options, bonds, international equities, and forex in a single platform. If your product needs to support more than US equities and crypto, Interactive Brokers is the only API that covers the full asset class breadth without building separate integrations. The failure points: the API is old. Interactive Brokers has a REST API now, but large parts of the documentation still describe their legacy TWS API (a desktop Java application from the early 2000s). The learning curve is steep and the API has known quirks that require workarounds documented in community forums rather than official docs. Interactive Brokers is also a retail brokerage competing with your product for the same users - their terms of service restrict how you can use their API in ways that create downstream product constraints.

Build vs. buy decision: specific thresholds

Use an existing brokerage (Robinhood, Public.com, Betterment) as-is when your audience is individual retail investors with no differentiated need. These products are free, reliable, and have years of trust built up. If you cannot articulate a specific reason your users cannot just use the existing product, do not build.

Build your own when at least one of these is true.

You have an existing user base that already trusts you with financial accounts. A crypto exchange with 50,000 verified users adding US equity trading is not competing with Robinhood from zero. They are giving existing users a reason not to leave the platform. The distribution advantage is real.

Your compliance requirements differ from what a general-purpose app can support. A halal investment screen, an ESG-only universe, or a fiduciary-grade retirement product all require a platform you control. The existing consumer apps cannot enforce restrictions at the product level.

Your revenue model depends on AUM or subscriptions, not payment for order flow. A $10/month membership model for an investment club works when your users are a defined community. It does not work when you are competing for anonymous retail users at scale.

You are replacing a third-party portal that costs more than building. Wealth management firms that pay $30K-$60K per year to license a client reporting portal can often justify a one-time $70K-$90K build that they own outright and can extend without negotiating feature requests with a vendor.

Do not build if you have no distribution advantage and no differentiated use case. A net-new consumer trading app with no existing audience, no specific niche, and no monetization model beyond PFOF (which requires scale to work) is competing with Robinhood for users who already have Robinhood installed.

Where these projects fail

The most consistent failure in trading app builds is underestimating account opening. Founders scope KYC as a two-week task. It consistently takes 6-10 weeks. Identity verification vendor integration, AML screening edge cases, state-specific disclosure requirements, and the account type selection flow (individual taxable, IRA, custodial, joint) each add time. The team that treats account opening as "just a form" will be debugging identity verification edge cases at the moment they expected to be in beta testing.

According to the FINRA Investor Education Foundation 2022 National Financial Capability Study, 61% of US adults owned investments in 2022, up from 52% in 2018. The market is genuinely growing. But the teams that try to serve it without a clear distribution story - who are your first 1,000 users and why do they use you instead of what they already have - hit a wall at launch.

The second failure is building the portfolio view before the data feed is stable. The portfolio chart is the product's daily driver. If it shows stale prices, users notice immediately. Build the market data integration first, validate it in production, and then build the UI that depends on it. Teams that invert this order ship a beautiful interface that displays wrong numbers and spend the first month post-launch firefighting data issues instead of onboarding users.

How RaftLabs builds trading and investment apps

We have built fintech products for equity platforms, crypto exchanges, employee equity portals, and wealth management firms. We know the Alpaca, DriveWealth, and Apex Clearing integration paths from production builds, not documentation reads. We have navigated the KYC vendor tradeoffs between Jumio, Persona, and Stripe Identity - each has different completion rates, pricing models, and support response times that matter in production. We have built the compliance audit logging that FINRA examiners look for, including the edge cases that no vendor documentation covers.

The first conversation is a scoping call where we map your regulatory path based on your specific product type, identify the right execution partner for your use case, and give you a timeline that accounts for the compliance work your engineers cannot rush. If the regulatory timeline makes your target launch date impossible, we will tell you that in week one rather than week twelve.

If you are evaluating whether to build or how to phase the build, book the scoping call and we will give you a straight answer.

Related reading: How to Build a Trading Platform covers institutional-grade execution infrastructure. AI Agents for Fintech covers how AI fits into fraud detection, KYC, and compliance workflows once the platform is live.