freetsa.org

What It Is

FreeTSA.org is a free timestamp authority service. Its core capability is issuing trusted UTC time proofs for files, code, PDFs, electronic signatures, images, videos, or hash lists based on the RFC 3161 timestamp protocol. Its value lies in proving that a given piece of data existed at a specific point in time, and in verifying whether the content has been changed after the timestamp was issued. The page also states that it provides public services such as OCSP, CRL, NTP, DNSCrypt, DNS, and DNS over TLS.

Core Features and Developer Integration

FreeTSA’s main endpoint is https://freetsa.org/tsr. Developers can use OpenSSL to generate a TimeStampRequest, then submit it with curl as application/timestamp-query to obtain a TimeStampResponse. The documentation provides complete commands for creating a tsq, submitting it to the tsr endpoint, downloading tsa.crt/cacert.pem, and verifying the result. It also includes an example TCP-based Perl client with IPv4/IPv6 support. In terms of algorithms, the main text lists sha1, sha224, sha256, sha384, and sha512, while the PDF guide mentions additional hashes and recommends SHA-512. The service also supports a Tor onion address, and its online signing tool states that files are not uploaded, making it suitable for lightweight proof-of-existence use cases.

Pricing and Compliance Boundaries

The main page clearly states that timestamp issuance and related network services are free. If a project or company wants to use FreeTSA for timestamping, the page recommends getting in touch to discuss specific requirements, but it does not disclose commercial plans, quotas, SLAs, payment methods, or support tiers. One important caveat is that the page also notes that legally binding timestamps depend on whether a timestamp authority is accepted under local law. As a result, FreeTSA is better suited to technical proofs and general evidence preservation; serious legal, judicial, or heavily regulated scenarios should be evaluated carefully.

Pros, Cons, and Best-Fit Users

Its strengths are adherence to open standards, low integration cost, clear command-line examples, and additional resources such as certificate hashes, a PDF signing guide, Tor access, and mobile browser usage instructions. The downsides are limited service governance information: it does not specify rate limits, availability commitments, audit reports, customer support channels, or self-hosting options. The PDF tool guide was also last updated quite some time ago, so some instructions may not apply to newer software versions. FreeTSA is a good fit for developers, open-source projects, individuals signing documents, and teams that need to prove the existence of file hash lists at a given time.

Access from China and Alternatives

The crawled content does not provide information about network availability in mainland China, payments, or local compliance, so its accessibility from China should be considered unknown. For formal electronic seals/signatures or judicial evidence preservation, it is advisable to also evaluate locally compliant Chinese e-signature or timestamp services. For purely technical verification, alternatives such as DigiCert, GlobalSign, Sectigo Timestamping, or OpenTimestamps can also be compared.