Alpaca vs Public
By Jay Rocco, Chief Editor, FullStack Alpha. Updated . Prices checked on each vendor's own site.
Quick answer
Pick Alpaca for automated trading plus backtesting. Pick Public for AI chat assistant plus stock screener.
Key differences
- AI chat assistant: Public (Only Public has it)
- Backtesting: Alpaca (Only Alpaca has it)
- Automated trading: Alpaca (Only Alpaca has it)
- Mobile app: Public (Only Public has it)
Pick Alpaca if
- You want trades placed automatically
- You test strategies before risking money
- Developers building trading bots
- Commission-free API trading
Pick Public if
- You want to ask an AI questions in plain English
- You scan the market with filters every day
- Multi-asset investing in one app
- Connecting AI assistants via MCP
Side by side
| Feature | Alpaca | Public |
|---|---|---|
| Starting price | Free, paid from $99/mo | Free plan |
| Free plan | Yes | Yes |
| Stock screener | No | Yes |
| Backtesting | Yes | No |
| Automated trading | Yes | No |
| Broker connection | Yes | Yes |
| Paper trading | Yes | No |
| AI chat assistant | No | Yes |
| Options analytics | Yes | Yes |
| Managed portfolios | No | Yes |
| Crypto | Yes | Yes |
| API access | Yes | Yes |
| MCP / AI connector | Yes | Yes |
| Mobile app | No | Yes |
Plans
Alpaca
- Basic data: Free
- Algo Trader Plus: $99/mo
Public
- Investing account: Free account, commission-free trading
Questions people ask
What is the main difference between Alpaca and Public?
Pick Alpaca for automated trading plus backtesting. Pick Public for AI chat assistant plus stock screener.
Which is cheaper, Alpaca or Public?
Their entry prices are hard to compare because one does not publish a monthly price. Alpaca: Free, paid from $99/mo. Public: Free plan.
Do Alpaca or Public have a free plan?
Both have a free plan.
Which is better for beginners?
Public is the friendlier start.
Which has better AI features?
Alpaca goes deeper on AI with 3 AI features (automated trading, MCP / AI connector, backtesting).
Can I connect Alpaca or Public to ChatGPT or Claude?
Alpaca and Public offer an MCP server or official AI connector.
Is Alpaca or Public better for active trading?
Public has more of the active-trading toolkit: alerts, scanning, signals and charts.
Should I use both Alpaca and Public?
It can make sense. They overlap on only 5 core features, so one can fill gaps the other leaves.