Holdstamp is a cryptocurrency recordkeeping app designed to help users document when and how they acquired each coin, across exchanges and wallets. It follows purchases and transfers so acquisition dates and costs remain connected to each holding, then produces an acquisition certificate as a PDF and CSV. Financial authorities, banks, or tax advisers can verify a certificate on Holdstamp’s website without creating an account or uploading a file.

Users can import transaction histories from supported exchanges, wallets, and other crypto tax platforms. Holdstamp organizes holdings into lots, highlights tax-holding periods and missing evidence, and provides portfolio views, timelines, and data checks. Its documents also include bank provenance records, exchange deposit summaries, DAC8 overviews, and materials for estate planning. Optional timestamps and file checksums help recipients verify that records have not changed.

The app operates locally on the user’s device and is read-only: it does not require API keys, seed phrases, or private keys. Holdstamp also offers informational tools, including a holding-period calculator and an old-holdings checklist.