Docs · Paper vs. live mode
Paper vs. live mode
What changes when you switch from Alpaca paper trading to a live account — real money, real fees, PDT rules, and what the UI shows differently.
Paper mode is a faithful sandbox, but a few things behave differently from live trading. Read this before connecting a live key.
Quick comparison
| Behavior | Paper mode | Live mode |
|---|---|---|
| Money at risk | None | Real |
| Order fills | Simulated by Alpaca | Real broker fills |
| Equity fees | $0 (simulated) | $0 commission today; CAT fee from 2026-06-01 |
| Crypto fees | Modeled (0.5% round-trip estimate) | Broker-reported (pulled from Alpaca) |
| News + AI evaluation | Same as live | Same as paper |
| Pattern detection | Same as live | Same as paper |
| PDT rules | Not enforced by Alpaca | Enforced (3-day-trade limit if account < $25k) |
| Circuit breaker | Active (5% daily loss → trading pauses) | Active |
| Margin / shorting | Equity shorts allowed (simulated) | Real margin rules apply |
| Crypto shorting | Blocked (Alpaca doesn’t support) | Blocked (same) |
What stays exactly the same
- Pattern detection. Same 16 patterns on the same timeframe (1-hour).
- AI evaluation. Same Claude model, same prompt, same confidence bands.
- News + on-chain confluence. Same signal pipeline.
- Sizing math. Same position-sizing rules — risk-percent of balance, volatility-based stops, 2:1 reward-to-risk targets.
- Trail/ratchet logic. Same profit-locking trail rules.
- Risk profile and tier limits. Conservative/Moderate/Aggressive map identically.
The signal you see fire in paper would fire in live too, with the same shape and size.
What’s different — fees
The biggest practical difference is crypto fees.
Alpaca’s paper-trading API doesn’t return crypto fee rows. So when a crypto trade closes in paper, Thesis estimates the round-trip cost using a calibrated rate (0.1875% per side, matching live Alpaca crypto spread). That estimate is what you see in the Fee breakdown panel and the trade-log subtitle, labeled (modeled).
On a live connection, the same panel shows the broker-reported fee from Alpaca — usually within a few cents of the estimate, but not identical. Thesis polls Alpaca every few minutes and replaces the modeled fee with the real one.
Why the calibration? If we showed $0.00 fee for paper crypto, the daily P/L would be wildly more optimistic than live. Modeled fees keep paper performance honest to what you’d actually realize.
See How fees work for the full breakdown.
What’s different — PDT
If your account is under $25k, FINRA’s Pattern Day Trader rule limits you to 3 day trades in any 5 business days. Alpaca enforces this on live; paper doesn’t.
Thesis applies a PDT-aware hold rule to equity trades regardless of mode: if you’ve already used one day trade today and a stop would normally fire on an equity position, Thesis suppresses it and lets the trade hold for its target (up to a hard drawdown floor that protects you from a runaway loss). That keeps you from accidentally racking up day trades on bad fills.
If you upgrade to Pro+ AND have ≥$25k equity AND sign the in-app PDT acknowledgment, that gate relaxes — you’re explicitly opting in to unlimited day trading.
What’s different — circuit breaker
The per-user circuit breaker pauses your trading if your realized P/L for the day breaches −5% of starting equity. This is identical in paper and live. Other users’ breakers don’t affect you.
To re-enable: open Settings, flip Trading paused to off. The system will start taking signals again on the next pattern.
When to graduate from paper to live
There’s no fixed answer, but a reasonable bar:
- You’ve watched at least 10 full round-trips in paper and understand what each one did and why.
- You’ve read this page, How fees work, and the Risk Disclaimer.
- You’re comfortable with the size Thesis picks at your risk profile — preview it on a paper trade before going live.
- You’ve decided in advance what loss you’d accept on a bad week. Trading involves real loss of capital.
When you’re ready, see Connecting an Alpaca API key for the live-key flow.
How to switch
In Thesis, Settings → Connect Alpaca lets you add a second connection (paper + live can coexist). Toggle the active one — only one is active at a time, and trades route to that account.
Important: Switching from paper to live does not carry over open positions. Each connection has its own ledger. If you close everything in paper before flipping, you start the live session from a clean slate — recommended.