How a Local Investing App Offers US Stocks: Inside Alpaca

A customer opens a local investing app, deposits money, and buys $100 of a US-listed exchange-traded fund. The app uses a familiar language, shows familiar payment methods, and answers questions through a local support team.

Behind that experience, somebody must open an account, receive the money, handle the order, hold the securities, and keep records after the purchase. A dividend months later still needs to reach the right customer. A correction to yesterday’s trade still needs to reach today’s balance.

Brokerage as a service lets a company buy much of that infrastructure from a specialist. Alpaca is one example: its Broker API lets partners build customer investing experiences around account opening, funding, and trading. Its separate Trading API serves developers building their own trading workflows. Alpaca Broker API introduction

The useful way to understand the business is to follow that $100 purchase and identify which company performs each job.

The local app has an infrastructure partner

Alpaca’s partnership with Midas makes the arrangement concrete. In a March 2026 case study, Alpaca describes the Turkish platform launching US stocks through its Broker API in 2021. That gives a local business a route to offering US securities through an upstream brokerage stack. Midas case study

The category extends beyond Alpaca. DriveWealth documents account opening, trading, clearing, custody, and reporting for embedded investing. Apex describes its own clearing and custody role for financial platforms. The infrastructure provider can be different even when two customer apps look similar. DriveWealth developer introduction, Apex clearing and custody

The application programming interface, or API, is how the partner’s software asks for an action and receives information back. The financial service behind that interface is what makes the integration useful. A request to buy an ETF needs an eligible account, money or credit, market access, and records that survive the request itself.

Alpaca describes itself as self-clearing for equities, with connections to market infrastructure and external execution providers. Its platform documentation also identifies banking and international-funding partners. Self-clearing therefore tells us something about Alpaca’s role in processing trades; it does not turn Alpaca into the stock exchange or remove the banking system. Alpaca platform architecture

First establish whose account it is

Before tracing an order, establish the account relationship. A customer identifier in an app can refer to different legal and operational arrangements.

In Alpaca’s fully disclosed broker-dealer model, the local broker introduces customers whose individual information is supplied to Alpaca. In an omnibus model, the partner holds the upstream relationship and maintains the underlying customer accounting. These models allocate work differently, including customer identification and reporting. Alpaca’s documentation describes registered broker-dealers in their respective jurisdictions; an API connection alone does not establish permission to offer securities locally. Integration models

Alpaca also offers OmniSub. The partner has one omnibus brokerage account, with technology subaccounts for tracking individual activity. Those subaccounts are internal accounting records rather than separate customer brokerage accounts at Alpaca. The product documentation assigns end-customer compliance, tax reporting, and customer statements to the partner. OmniSub documentation

For an operator, the immediate questions are practical. Which account does this payment fund? Where is the customer’s position recorded? Which firm produces the official statement? If one customer’s balance is wrong, which records must reconcile before it can be corrected?

Ownership has another layer. Securities held through a broker are commonly registered in an intermediary’s name while the broker’s records identify the beneficial owner. The SEC and FINRA describe this as holding in street name. Direct registration is a different arrangement. The app’s display should therefore agree with the relevant custody and account records, rather than imply that the investor appears directly on the issuer’s register. SEC/FINRA securities-holding bulletin

Buying power can arrive before cash

Return to the $100 purchase. For the following example, assume an eligible customer account and a partner approved to use an instant-funding arrangement. Ignore fees and currency conversion so we can isolate the funding obligation. These are example assumptions, not the terms of a named local app.

The customer pays the local platform. The platform records the payment and makes buying power available through its provider. The customer buys $100 of the ETF while the platform’s aggregate payment to the provider is still pending.

There are now several facts to retain:

Record	What it establishes
Customer payment	The platform has received or recorded the customer’s funding
Buying-power allocation	The account has permission and capacity to trade
Trade execution	The purchase occurred at recorded quantities and prices
Partner funding obligation	The platform still needs to deliver the required money upstream

Alpaca’s Instant Funding documentation makes that last obligation explicit. Partners can extend buying power before funds settle at Alpaca, then send aggregate funds and reconcile the relevant transfers. The documented deadline is 1 p.m. Eastern Time on T+1. Late or unreconciled funding has consequences, including interest and cancellation of outstanding credits under the documented process. Instant Funding

The screen can respond quickly because an operating arrangement bridges the delay. Treasury still needs to know the amount due, where the funds are, and whether the bank transfer will arrive in time.

A fill and a settlement answer different questions

Suppose the order executes. The execution record supplies the quantity and price. Clearing establishes and processes the obligations resulting from trading. Settlement completes the relevant delivery of securities and payment.

For most covered US securities transactions, the standard settlement cycle is T+1: one business day after the trade date. The shorter cycle took effect in May 2024. The rules have exceptions, so a description of US-stock settlement should not become a statement about every instrument or transaction. SEC settlement-cycle FAQ

The partner’s funding deadline and securities settlement can both use the label T+1 while referring to different obligations. One concerns paying for the partner’s instant-funding transfers. The other concerns the securities trade. A customer’s later withdrawal introduces another payment path and another set of conditions.

An app that collapses these records into one green checkmark makes investigation harder. An operator needs to distinguish a missing trade report from an unsettled funding obligation and a delayed bank payout. Each requires a different action.

The position must remain correct tomorrow

The ETF purchase creates ongoing work. Cash distributions, fees, transfers, and trade corrections change financial records after the order disappears from the screen.

Alpaca’s activity documentation expects partners to maintain a backend view of customer financial state. It describes replaying financial events after a disconnection, identifying duplicates, and processing corrections. It also distinguishes financial activities from order-lifecycle messages such as acceptance and cancellation. A record of financial changes does not supply every order-status transition. Activity stream documentation

Consider a hypothetical interruption. The trade executes, but the local app disconnects before processing the event. When the customer returns, the app shows cash and no ETF position.

Submitting another purchase would create additional exposure. A useful recovery process first checks the original order and executions, retrieves missing activity, and updates the local records once. The customer should see the result supported by the provider’s records, with the unresolved state visible until the investigation finishes.

This remains financial operations even when software performs most of it. The provider and the application need records that can be compared, references that identify the same transaction, and a defined way to correct a disagreement.

Commission-free trading still has a business model

Alpaca’s January 2025 customer relationship summary discloses several revenue mechanisms: payment for order flow, margin interest, stock-borrow fees, and income associated with customer cash. It also explains that fees through an authorized partner can depend on that partner’s arrangement. Those disclosures identify incentives; they do not tell us Alpaca’s enterprise pricing or revenue mix. Alpaca Form CRS

The local platform has its own economics. A sensible comparison would include provider charges, payment and foreign-exchange costs where relevant, funding costs, customer support, and the work of resolving exceptions. A low visible trading commission supplies only part of that calculation.

Customer protection also needs precise language. SIPC protection concerns eligible customer property at a member brokerage in a qualifying failure, subject to its rules and limits. It does not compensate for market losses. An omnibus structure needs its own analysis of the customer relationship; a logo cannot answer that for every end user. SIPC introduction

The operating test comes when something is unfinished

The local platform buys access to a substantial brokerage stack. It still has to understand the agreement it is operating under and the obligations that agreement creates.

For the $100 purchase, a useful handoff record would identify the customer account, payment, order, executions, funding settlement, and subsequent position. A support team should be able to say which step is complete and which organization can resolve the next one.

Before promising instant investing, follow the same customer through a sale and withdrawal. Identify the first point where the app depends on funds, records, or approval it does not control. That is where the operating arrangement needs to be clearest.

This is the first article in a three-part series on brokerage infrastructure. The next follows crypto liquidity sourcing and embedded trading services. Provider documentation was checked on 25 October 2026; the transaction example and diagrams are explanatory, not a description of an undisclosed client integration.