Frequently Asked Questions
Everything You Need to Know
Below are answers to the most common questions about using VerifyFirst—including how to timestamp, verify, add cover letters and expiration dates, and more.
General Questions
How do I create a timestamp?
To timestamp a document, navigate to the Timestamp page, upload your file (PDF, .docx, image, etc.), and optionally attach a cover letter or specify an expiration date. Once you submit, VerifyFirst computes a SHA-256 hash of your file, anchors it on the Bitcoin blockchain using the OpenTimestamps protocol, and returns a unique proof record. You’ll see a confirmation with your file’s hash and a link to download the .ots proof file for safekeeping.
How do I verify a timestamped document?
To verify that a document has been anchored on the blockchain, go to the Verify page. You can either upload the same file again (VerifyFirst will hash it in your browser) or upload the .ots proof file. Once submitted, our system will check the associated proof against the blockchain and display the verification status, including block height and transaction ID. If confirmed, you’ll know that the document existed at the timestamp you originally requested.
How do I add an expiration date to my timestamp?
When creating a timestamp, the Timestamp form includes an optional “Expiration Date” field. Enter the number of months (e.g., “6” for six months) or pick a specific date. VerifyFirst will automatically schedule email and webhook notifications to alert you (or your chosen recipients) when the document is within seven days—or any custom period—of expiring. You can manage these notifications in your account settings.
How do I include a cover letter with my timestamp?
If you want to attach a cover letter (for example, a PDF that explains the context or purpose of the timestamp), click “Add Cover Letter” on the Timestamp page. Upload your cover letter file in the designated field. VerifyFirst will hash your main document and the cover letter separately, anchor both proofs on the blockchain, and store them together in your record. This is useful when you need to package a legal declaration, terms of use, or any additional instructions with the original file.
How do I log in and manage my API keys?
To access the API or view your timestamp history, you need a VerifyFirst account. Visit Login (or Register if you’re new) and create a username/password. Once logged in, navigate to “API Keys” under your profile menu. From there, you can generate new keys, set monthly quotas, and view usage stats. Use these API keys to authenticate any REST calls to POST /verifyfirst/v1/timestamp, GET /verifyfirst/v1/verify/{file_hash}, or other endpoints.
Can I revoke a timestamp? What happens then?
Yes. If you need to invalidate a previously anchored proof—because ownership changed or the document is no longer valid—you can use our Revoke API or the “Revoke” dashboard in your account. Once revoked, the record’s status changes to “Revoked,” and any future verification attempts will show the proof as invalid. We store a revocation hash on the blockchain to indicate the timestamp has been intentionally canceled, preserving transparency and auditability.
How private is my document? Does VerifyFirst store my file?
By design, VerifyFirst only stores the SHA-256 hash of your document and not the plaintext file. During timestamping, we compute this hash on your device or our server (depending on your chosen mode) and anchor it. The original file itself is never publicly exposed, and any uploaded files are deleted immediately after hashing. Only the resulting .ots proof and your hash are kept, so the content of your document remains private and confidential.
How do I download and store my .ots proof file?
After successfully timestamping, your dashboard and the confirmation email will include a link to download the .ots proof file. You can also find it later under “My Timestamps” in your account. Click “Download Proof” to save the file locally—keeping it alongside your original document is recommended. This .ots file is the cryptographic proof you or any third party can use to verify existence and timestamp without re-uploading the actual document.
Where can I find API documentation?
Our full developer documentation (including endpoints for Timestamp, Verify, Revoke, and Webhook setup) is available at /api-docs. It provides request/response examples in cURL, Python, and JavaScript, along with authentication instructions, rate limits, and sample code snippets to integrate VerifyFirst into your application quickly.
Still Have Questions?
If you don’t see your question here, get in touch with our support team or explore our API documentation for more details.
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