The safest upload is no upload.
Jason processes spreadsheet content on your machine. Payment and licensing are separate from the data plane.
Rows stay local.
Source content is imported, queried, edited, calculated, and exported in the browser. Local projects remain on the device.
Entitlements stay narrow.
Polar handles checkout. Jason reads only the customer and subscription facts needed to issue a signed Pro receipt.
Fail closed is a product requirement.
Pro is granted only when the product can verify a subject-bound ES256 licence receipt. Missing keys, malformed receipts, unknown users, expired grace windows, and clock rollback do not silently unlock paid capability.
- Receipt
- Short-lived, signed, versioned, and bound to the account subject.
- Offline use
- Bounded grace from the last verified receipt, not permanent trust.
- Clock defence
- A local high-water time prevents simple clock rollback.
- Live check
- Each receipt issuance rechecks the customer and subscription directly with Polar.
Current launch state
This deployment uses Polar live checkout. Polar accepts real payments only after seller verification and website approval are complete.
Stop shrinking the question to fit the tool.
Open an oversized CSV for free. Pro removes Jason's limits and adds structured-data, document, and multi-file Local Data Suite tools.