Alpaca vs Interactive Brokers: Which Is Better in 2026?

Figures and features are point-in-time and change; treat the table as a starting map, not a live quote.

A developer-first brokerage with an official MCP server for real-time data, paper trading, and execution by AI agents. Best for people who code.

How it works: Alpaca is a brokerage you talk to through code: a REST and websocket API exposes market data, paper trading, and live commission-free execution, and its official MCP server lets an AI agent pull data, test in a paper account, and place real orders programmatically. You build (or wire up an agent against) that API rather than tapping buttons in an app.

In practice, Alpaca’s AI official mcp server (data + execution). It falls under for builders: connect a broker to an ai agent, which makes it best suited to developers building ai agents. On connecting an account it is “Alpaca accounts”, and on execution it is “Read + trade + paper”. It is priced as free (open source).

One honest limitation: Developer-first; requires code and self-hosting.

Broad market access with AI-integration options and community-built MCP connectors. Best for advanced and international investors.

How it works: Interactive Brokers gives you broad global market access through professional platforms (like Trader Workstation) and a deep API. AI integration is possible by wiring tools to that API or using community-built MCP connectors, but there is no polished, official consumer AI assistant, so the AI layer is something you or a developer assemble.

In practice, Interactive Brokers’s AI ai-integration options (community mcp). It falls under for builders: connect a broker to an ai agent, which makes it best suited to advanced and international investors. On connecting an account it is “IBKR accounts”, and on execution it is “Read + trade”. It is priced as brokerage fees.

One honest limitation: Powerful but complex; AI connectors are mostly community-built.

The core difference is category. Alpaca focuses on developers building ai agents (official mcp server (data + execution)), and Interactive Brokers on advanced and international investors (ai-integration options (community mcp)). On broker connection they differ too: Alpaca is “Alpaca accounts” versus Interactive Brokers at “IBKR accounts”. That shapes everything downstream: how personal the answers are, where trades settle, and how much control you keep over individual positions.

Every tool gives something up for what it does well. Here is the honest give-and-take on each, so you can weigh the specific strengths against the limitations that come with them rather than judging on the headline category alone.

For AI investing tools, the distinction that matters most is whether the tool works from your actual, connected positions or reasons from something else: a separate account it manages for you, or the tickers and numbers you feed it. It decides how personal the answers can be, and where your money physically lives.

• Alpaca: connects specific supported accounts. Alpaca connects a defined set of accounts (Alpaca accounts), so whether it can see your holdings depends on whether your money is at one of them.
• Interactive Brokers: connects specific supported accounts. Interactive Brokers connects a defined set of accounts (IBKR accounts), so whether it can see your holdings depends on whether your money is at one of them.

On this specific question the two land on the same side, so the deciding factors between them are elsewhere: category, cost, and who each is built for. This holdings-aware angle is the one Walnut is built around: it connects the brokerage you already use and reasons from your live positions, read-only by default, with any trades left for you to approve.

There is no universal winner here; the right pick depends on the job you are hiring the tool for. Match the category to your intent rather than chasing a single “best.”

• Choose Alpaca if you want developers building ai agents. Its AI official mcp server (data + execution), it is priced as free (open source), and it fits for builders: connect a broker to an ai agent. It is built for developers building their own automated or AI-driven trading systems. Keep in mind that developer-first; requires code and self-hosting.
• Choose Interactive Brokers if you want advanced and international investors. Its AI ai-integration options (community mcp), it is priced as brokerage fees, and it fits for builders: connect a broker to an ai agent. It is built for advanced or international investors who want breadth and are comfortable with complex tools. Keep in mind that powerful but complex; ai connectors are mostly community-built.

Because both sit in the same category, the choice comes down to the finer details above rather than a fundamental difference in approach.

Cost is easy to misread when two tools charge in different shapes, so compare the model, not just the number. Alpaca is priced as free (open source), while Interactive Brokers is priced as brokerage fees. A percentage-of-assets fee scales with your balance, a flat subscription does not, and a “free” tier usually earns elsewhere (on cash, order flow, or premium upgrades), so the cheapest headline is not always the cheapest outcome for your situation.

Pricing and tiers change often. Confirm the current numbers on each provider’s own site before you decide; the framing above is point-in-time.

If neither quite fits, Walnut sits in a third category: chat-driven management of your own brokerage. It connects the brokerage you already use through SnapTrade, lets you analyze and manage it by talking through Claude or ChatGPT, build thematic portfolios around a thesis, and place trades you approve. Read-only by default. See Walnut vs Alpaca and Walnut vs Interactive Brokers. Walnut is not an investment adviser.