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Licence agreement

Last changed 10 November 2026.

This agreement is between you and Phan Vu Chau (“we”), the maker of Rearview. By installing or using Rearview you accept it. If you don’t, don’t install it, and if you bought a licence, you can have a refund within 30 days under our refund policy. You must be 18 or older, or old enough to make a binding contract where you live.

“Rearview” here means the app, its rvw command-line tool, its documentation and its example scripts.

Who sells it

You buy Rearview from FastSpring, our payment provider and the merchant of record. It takes your payment, collects any tax and makes refunds, under its own terms. This agreement covers your use of the software, and is between you and us.

Your licence

  • One person, on the Macs they use. A licence lets one person use Rearview on any Mac they use. It is personal and can’t be shared, sold or transferred.
  • The version you buy, for good. A licence covers every version we release during its update year: the 12 months after you buy, and each year you renew. You may use those versions for as long as you like, and Rearview keeps working when your updates end. A renewal adds 12 months, counted from the day you renew or the day your updates end, whichever is later.
  • Correctness fixes for everyone. When we fix a wrong result, we release the fix to every licence holder, even after their updates have ended.
  • The trial. Without a licence, Rearview runs as a trial for 30 days from the first time you use it to compute anything: a backtest, a search, a scan, a check or a live account’s update. Opening Rearview, importing data and writing scripts don’t start it. When the trial ends, Rearview opens and exports your saved runs, but makes no new ones.
  • For your own trading. Rearview is licensed for one person’s own research and trading, including through a company or trading account that person runs alone. It isn’t licensed for use by a team, for work done for clients, or to provide results or signals to others as a service.

What is whose

Rearview is licensed, not sold, and we keep every right in it that this agreement doesn’t give you. You keep every right in your scripts, data, runs and reports. You may copy and change the example scripts and the language reference for your own work.

What you may not do

  • Share your licence key, or use Rearview past what your licence allows.
  • Copy, sell, rent or sublicense Rearview, or remove its copyright notices.
  • Take Rearview apart (decompile, disassemble or reverse engineer it), except where the law allows that despite this agreement.

Your data and your orders

  • Your data. You supply the market data Rearview reads, and you are responsible for having the right to use it. Most data vendors allow personal use only. We don’t supply market data and can’t vouch for yours: results are only as good as the data. Rearview doesn’t send your data anywhere, unless you choose to send us a report.
  • Your orders. Rearview can list orders for the next session. They come from your script and your data. Check them before you place them; placing them is your decision. Rearview never places orders.
  • Your backups. You are responsible for keeping copies of your scripts, data and runs.

No advice

Rearview is software for testing your own rules on historical data. It gives no trading signals or advice of its own. Nothing in Rearview, its documentation, its example strategies or this website is investment advice, a recommendation or a signal to trade. The example strategies are educational templates.

Backtest results are hypothetical. They are based on hindsight, not actual trading, and can’t reflect everything that happens in real markets, such as the effect of your own orders on prices. Past results don’t predict future ones.

Trading can lose money. Short selling, margin, futures and forex can lose more than you put in. Rearview can model them, but a model isn’t a market. We aren’t a broker, dealer, investment adviser or commodity trading adviser, and nothing here makes us your adviser. You decide what to trade, and the result is yours.

Our software, as it is

Rearview is provided “as is” and “as available”. To the fullest extent the law allows, we give no warranty of any kind, express or implied, including any warranty of merchantability, fitness for a particular purpose, non-infringement or accuracy of results, or that Rearview will be free of errors or run without interruption.

We test Rearview’s results and publish how in How Rearview is checked. That describes our testing; it doesn’t promise that any result is right. Releasing a fix when we find a wrong result is how we put one right, not a warranty.

Limits on our liability

To the extent the law allows, we aren’t liable for any trading loss, lost profit, lost data, or any indirect, incidental, special or consequential loss, however it arises and even if we were told it was possible. Our total liability for all claims about Rearview is limited to the greater of what you paid us for Rearview in the 12 months before the claim and US$50.

Nothing in this agreement limits liability that the law doesn’t allow us to limit. Where the law doesn’t allow these limits in full, they apply as far as it does.

If Rearview is discontinued

If we decide to stop maintaining Rearview, we will first release a final version with the licence check removed, so the version you have keeps working.

Ending this agreement

Your licence ends if you break this agreement, if the order it came from is refunded or charged back, or when you stop using Rearview and delete it. When it ends you must stop using Rearview. The sections on what is whose, no advice, our software, our liability and the rest still apply after it ends.

The rest

  • Changes. We may change these terms for future versions. The version you bought stays under the terms it came with, and the date at the top says when they last changed.
  • Law and courts. This agreement is governed by the laws of the Commonwealth of Pennsylvania, United States, without regard to its conflict-of-laws rules. Claims about it go to the state courts in Philadelphia County, Pennsylvania, or the federal court for the Eastern District of Pennsylvania, and you and we accept those courts. If you use Rearview as a consumer, the mandatory consumer laws of the country where you live still apply to you.
  • The whole agreement. This is the whole agreement about Rearview. If a court finds part of it unenforceable, the rest stays in force. If we don’t enforce a term, we haven’t given it up. We may transfer this agreement to whoever takes over Rearview; you may not transfer yours.
  • Export. You may not use Rearview where US export controls or sanctions forbid it.
  • Contact. Write to support@rearview.page.