BasisScout is a wash-sale check API. Send your own trades, across any accounts, and ask whether buying or selling a ticker on a date would wash a loss under the US rule (IRC section 1091). A broker reports wash sales only inside one account; everything cross-account, in an IRA or in a spouse’s account is the taxpayer’s own job on Form 8949, and an IRA repurchase loses the loss for good. BasisScout applies the rule to all of it at once: the disallowed loss and which purchase caused it, the adjusted basis and holding date the replacement shares carry, the first safe rebuy date, and the year’s realized gains split short and long term.
Every answer is a rule calculation on the trades sent, in sentences that state the rule and never recommend a trade. Nothing sent is stored.
Machine-payable over x402 (HTTP 402): $0.01 per check, USDC on Base, Arbitrum, Polygon or Solana, or XRP / RLUSD on the XRP Ledger. Free preview: /preview · OpenAPI: /openapi.json · payment discovery: /.well-known/x402 · A2A agent card: /.well-known/agent-card.json · llms.txt.
Operated by ScalpStream. A record-keeping calculation under IRC section 1091 as IRS Publication 550 describes it; not tax advice. Not affiliated with the IRS or any broker.