🔒 Runs in your browser — no signup, no account linking, trades never uploaded
Never eat a wash-sale
surprise again.
Your broker only tracks wash sales inside one account. The IRS counts them across every account you and your spouse own — including IRAs. Most traders find out in February, from a 1099-B, when it's permanent.
Drop broker CSVs · results in seconds · keeps working offline once the tab is open
The trap, in one example
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Jul 5 — you harvest a loss
You sell NVDA at a $4,000 loss in your Schwab taxable account. Smart tax-loss harvesting… so far.
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Jul 18 — you re-buy elsewhere
The dip looks juicy, so you buy NVDA back — in your Robinhood account. Or worse, your IRA auto-invests into it. Neither broker warns you. Neither one can see the other.
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February — the 1099 lands
The $4,000 deduction is disallowed. If the re-buy was in your IRA, it's gone forever — no basis adjustment, no do-over, and it shows up on no broker's 1099.
This is common enough that the IRS wrote a ruling about the IRA version (Rev. Rul. 2008-5) — and one Robinhood trader famously racked up an $800,000 tax bill on $45,000 of profit largely from wash sales.
What Wash-Sale Guardian does
1 · Drop your CSVs
Robinhood, Schwab, Fidelity, IBKR, E*TRADE — or any CSV with the column mapper. Tag each file taxable or IRA.
2 · See your danger windows
"Don't re-buy NVDA in any account before Aug 5." Live 30-day windows across every account, plus violations you've already incurred, with dollar amounts.
3 · Hand your CPA the summary
Year-end adjusted-basis report per lot — reconcile it against your 1099-Bs before TurboTax takes them at face value.
Why there's no "connect your brokerage" button
Other tools want you to link your accounts through an aggregator. We think handing a startup your brokerage login is exactly backwards. Wash-Sale Guardian parses CSV exports locally in your browser — this site works offline once loaded, and the app page loads zero third-party scripts. Your trades never touch a server because there is no server.
Get warned before a window closes
Weekly danger-window digests and a "can I buy X today?" checker are coming for tax-loss-harvest season. Join the early list — free during beta, early-bird pricing at launch.
One field, your email. Your trades stay in your browser, always.
Questions traders ask
- Is my trade data uploaded anywhere?
- No. Parsing and analysis run in your browser; the ledger is stored in your browser's local database. Verify it yourself: open DevTools → Network, or switch to airplane mode with the tab open — it keeps working until you close it.
- Do I have to re-upload constantly?
- No — your ledger persists in the browser between visits, and one upload answers "can I re-buy X?" correctly for up to 30 days. Refresh when you make new trades (there's also a 10-second manual entry for a quick patch), and download the one-file ledger backup to move devices.
- What does it NOT handle?
- Short positions, option exercise/assignment, and cross-ticker "substantially identical" calls (SPY vs VOO) are out of scope for now — and the tool tells you loudly when it sees them instead of guessing. It also refuses to give verdicts on symbols with incomplete history.
- Is this tax advice?
- No. It's a conservative early-warning system. For filing decisions, bring the year-end summary to a CPA — that's exactly what it's designed for.