Stampery

Stampery Review Guide: Everything You Need to Know + FAQ

Ever needed to prove you created a file first—without paying a notary, emailing yourself a copy, or trusting a third party that might disappear? If that’s your world, you’re in the right place.

When you’re shipping a product, drafting a contract, submitting research, or logging an incident, you don’t just need a file—you need proof. Proof that it existed at a specific time. Proof it hasn’t been changed. Proof that holds up even if the vendor changes their pricing or shuts down.

“If your evidence depends on a vendor staying alive, it’s not a proof—it’s a hope.”

That’s the promise of Stampery: cryptographic proof for your documents and data, anchored on public blockchains like Bitcoin and Ethereum, so you can verify it anytime—without exposing your content.

The problem: proving authorship, integrity, or timestamps is harder than it looks

Old-school tricks and one-off fixes don’t cut it when real stakes are involved:

• Emailing yourself a file can be faked, backdated, or challenged. It’s weak evidence in any serious dispute.


• Traditional notarization is slow and doesn’t scale for teams or frequent releases. It’s also expensive for repeat workflows.


• Cloud storage timestamps aren’t designed as legal proof. Providers can change metadata, and access logs aren’t always airtight.


• Vendor lock-in is risky: if the service holding your proof shuts down, what happens to your evidence?

Real-world stakes make this urgent:

• IP and authorship: Proving who had a design first—before a pitch or a client handoff.


• Contracts and policies: Freezing the exact version both parties agreed on.


• Research and lab work: Establishing tamper-proof, time-stamped records of experiments and results.


• Security and compliance: Locking in incident timelines and system logs to prevent later tampering.

Courts and regulators are catching up too. In 2018, China’s Supreme People’s Court confirmed that blockchain records can be used as evidence in internet courts. In the U.S., states like Vermont created a presumption of authenticity for blockchain records (12 V.S.A. § 1913), and Arizona acknowledged smart contracts and blockchain signatures in commerce (HB 2417). In the EU, eIDAS gives legal weight to electronic timestamps (blockchain can support these workflows, even if not all services provide “qualified” timestamps). The short version: technical proofs are increasingly welcome in serious settings—when done right.

The promise

Stampery creates a tamper-proof fingerprint (hash) of your data and anchors it to public blockchains. You keep your content private; the chain proves the existence and integrity of whatever you hashed, at or before a specific time. Anyone can verify it later—independently.

• No file exposure: Only the cryptographic hash is anchored, not your content.


• Independent verification: Proofs can be checked on public chains, not just on the vendor’s servers.


• Strong security model: Bitcoin/Ethereum anchoring means tampering is prohibitively expensive.

Who this is for

• Creators and startups: Designs, drafts, demos, and release snapshots you can actually defend.


• Developers: CI/CD releases, commit hashes, SBOMs, and supply-chain attestations.


• Legal and compliance teams: Contract versions, policy changes, and audit trails that don’t depend on trust.


• Researchers and labs: Time-stamped notebooks, datasets, and results without leaking IP.


• Security and ops: Immutable logs and incident timelines for postmortems and regulators.

What you’ll get in this guide

I’ll walk you through how blockchain timestamping works in practice, where Stampery fits, and how to use it with confidence—without fluff.

• Clear overview of the tool and how the proofs actually work


• Real workflows for product releases, contracts, research, and logs


• Pricing and limits: what typically drives your bill


• Security and privacy: what’s stored, what isn’t, and why it matters


• Pros, cons, and alternatives: when to pick SaaS vs open-source


• Straight answers to common questions: “Is it legal?”, “Is it free?”, “What if the service shuts down?”, “How do I verify proofs without the website?”

Curious how Stampery actually works under the hood—and what, precisely, it proves? That’s next. Ready to see the simple version and then the technical one?

What is Stampery? The simple version and the technical one

Think of Stampery as a “truth machine” for your files. You take a document, photo, contract, commit, or data blob, and turn it into a unique fingerprint (a cryptographic hash). Stampery anchors that fingerprint to public blockchains like Bitcoin and Ethereum, then gives you a certificate that anyone can verify independently, now or ten years from now.

“Don’t trust. Verify.”

That’s the core value here. No need to reveal your content, no need to beg a third party to vouch for you, and no awkward “emailing it to myself” games. You get math and public ledgers on your side.

How blockchain timestamping works (in plain English)

Here’s the simple mental model I use when I explain it to teams:

• Fingerprint your data: Your file is turned into a short, unique code using a one-way function (e.g., SHA-256). Change a single pixel or character and the fingerprint changes completely.


• Batch and anchor: Stampery aggregates many fingerprints into a Merkle tree (a cryptographic structure) and publishes the tree’s root on a public blockchain transaction.


• Public timestamp: The transaction gets confirmed in a block with a network timestamp. That block is globally replicated and practically immutable.


• Independent verification: Later, you re-hash your file, reconstruct the Merkle path from your certificate, and check the on-chain transaction. If everything matches, you’ve proven the file existed at or before that time and hasn’t been altered.

Here’s a concrete example from my own workflow:

• I stamped Design_v12_final.pdf and got a proof showing the SHA-256 hash, a Merkle proof, and a Bitcoin transaction ID.


• Months later, I re-hashed the same file locally and confirmed the hash matched my proof.


• I checked the transaction on a public blockchain explorer and saw it confirmed in a block from that date. Result: I can prove the file existed unchanged back then—without showing anyone the file itself.

If you like to nerd out (I do), this approach aligns with how independent experts describe blockchain-based proofs of existence and integrity. See NIST’s “Blockchain Technology Overview” (NISTIR 8202) for a neutral, technical framing.

What you can prove with Stampery

At a practical level, this unlocks a bunch of “I need to be able to show this happened, exactly like this, at that time” moments:

• Existence and timestamp: Your research notes existed by March 3rd, 14:22 UTC.


• Integrity: The source code you shipped last quarter is byte-for-byte the same as what you present today.


• Version snapshots: A design or contract version was the “final” one everyone signed off on.


• Chain-of-custody: Security logs and incident evidence were not altered before review.


• IP groundwork: Early artifacts of an invention or creative work can be reliably tied to a time.

Notice what’s missing: your actual content. The proof anchors only the fingerprint, so your data stays private. Anyone can verify the proof without seeing the file’s contents.

Is this the same as a notary?

Not exactly. A blockchain timestamp is a strong technical proof. It demonstrates existence and integrity at a point in time with transparent, tamper-resistant backing. A traditional notary, on the other hand, is a legally designated witness who verifies identity and intent. In many scenarios, teams use both: the blockchain proof for airtight technical integrity and the notary or e-signature for formal legal process.

Two notes from the trenches:

• Evidence quality: Courts and auditors increasingly accept cryptographic timestamps as part of a broader evidence package, especially when procedures are consistent and well-documented. That’s consistent with general guidance on the reliability of digital evidence.


• Jurisdiction matters: Laws differ by country. Some regions have specific frameworks for qualified electronic timestamps, while others evaluate digital evidence on reliability and provenance. The tech proof is powerful, but pair it with good process.

Here’s the emotional kicker: when something is on the line—your reputation, your product launch, your IP—the last thing you want is doubt. “Can we prove this?” shouldn’t keep you up at night. With a good stamping habit, it won’t.

So what does this look like in action, step by step, from upload (or hash) to a certificate you can verify years later—without depending on any one company’s server? Ready to see it done in under a minute?

Hands-on: how to use Stampery step by step

I like tools that get out of the way. In a few minutes you can create a proof that’s tamper-evident, timestamped on public chains, and easy to verify years from now. Here’s exactly how I do it—no fluff, just the clicks and checks that matter.

Creating a proof (web or via hash)

First stamp, start here. I recommend organizing proofs by project so audits make sense later.

• Create a workspace/project: Think “Design v1.2” or “Q3 Contracts.” Clean names now save headaches later.


• Choose your input:
  
  
  
  • Upload the file: Easiest path. The app hashes the file and schedules an anchor on Bitcoin and/or Ethereum.
  
  
  • Or submit a hash only: For sensitive data, hash locally and paste the hash.
    
    
    
    • macOS: open Terminal and run shasum -a 256 yourfile.pdf
    
    
    • Windows: open PowerShell and run CertUtil -hashfile yourfile.pdf SHA256
    
    
    • Linux: run sha256sum yourfile.pdf
    
    
    
    
  
  
  
  


• Batching: Drop multiple files at once. They’ll be aggregated into a Merkle tree so you get one efficient on-chain anchor for many items.


• Anchoring cadence: Choose “as soon as possible” for time-sensitive stuff or larger batching windows for cost efficiency. More on how this affects your bill in the next section.


• Get the proof/certificate: You’ll receive a proof containing the file hash, the anchor transaction(s), block references, and a Merkle path. Save it as a JSON (and/or PDF export if available).

Tip: Store your proof files in the same repo or folder as the artifacts they certify. Future-you will thank present-you.

Real-world example I’ve used: I uploaded Alpha_Spec_v1.2.pdf, batched it with two PNG mockups, and anchored the set. I saved the certificate next to the spec in a /proofs subfolder and tagged the project in my tracker. Later, when someone asked “Did we have this wording in March?”, the proof answered for me.

Why SHA‑256? It’s a NIST-recommended hash function with strong collision resistance, and it’s the standard choice for this purpose. If you like to read the underlying guidance, check NIST FIPS 180‑4 at csrc.nist.gov.

Verifying a proof (now and years later)

Verifying should not depend on any single company. That’s the point of using public chains.

• Quick check: Use the built-in verifier—upload the certificate or paste the proof data. It should confirm the hash, show the on-chain transaction(s), and the earliest trustworthy timestamp.


• Independent check (no platform needed):
  
  
  
  • Recompute the file hash locally (use the same SHA‑256 commands as above).
  
  
  • Open the transaction IDs from the certificate in a public explorer (for example, any reputable Bitcoin or Ethereum explorer).
  
  
  • Confirm the transaction is in a block with sufficient confirmations and note the block time.
  
  
  • Validate the Merkle path from your proof file to the anchor root. If your proof is OpenTimestamps- or Chainpoint-compatible, open-source verifiers can do this. One popular starting point: OpenTimestamps.
  
  
  
  


• Backups: Keep a 3–2–1 backup of your proof files (3 copies, 2 different media, 1 off-site). If you lose the certificate, you lose easy verification.

“Trust is good; math is better.”

If you’re new to this, the first independent verification might feel technical. It quickly becomes second nature: hash the file, check the tx, confirm the Merkle path. That’s it.

API and integrations for teams

For teams, the magic is in automation. Stamp the things that matter, exactly when they matter, without extra clicks.

• CI/CD releases: After your build produces an artifact (zip, container image, binary), compute the hash, call the API to stamp, save the returned certificate as a build artifact, and attach its tx IDs in your release notes.


• Log integrity: Roll logs hourly/daily, hash the roll, stamp the hash, and store the certificate alongside the log archive. This creates a tamper-evident audit trail for incident response.


• Design and doc portals: When a doc is marked “Final,” trigger a webhook that stamps the PDF and posts the certificate link to Slack or email for sign-off.


• Data pipelines: Hash snapshots of datasets at ingestion or transformation checkpoints. Stamp those hashes so any later analysis can prove exactly which data version was used.

What an API response typically contains: your submitted hash, anchor IDs (Bitcoin/Ethereum tx hashes), a Merkle path, timestamps, and a signature from the service. Store the raw JSON. It’s your self-contained proof package.

Common workflows and use cases

• Product design sign-offs: End of sprint, export the final PDF mockups, stamp them, attach the certificate to the sprint ticket. Now that “final” really is final.


• Contract finalization snapshots: Before you send a contract for signature, stamp the exact PDF. If edits happen, stamp again. You’ll always know which version was signed and when it existed.


• Research and lab notebooks: Zip your daily notes, raw data slices, and scripts. Stamp the zip. Later publications can reference the hash—provenance matters in peer review.


• Source code releases and commits: Stamp the release tarball or container digest. Mention the proof’s tx ID in the Git tag message so anyone can verify the build wasn’t swapped.


• Security logs and incident timelines: During incidents, stamp timeline notes or critical evidence bundles. If something is questioned later, you’ve got a tamper-evident clock.

Small pro tip: pair stamping with consistent naming. For example, project_v1.4_2025‑03‑10.pdf plus a matching project_v1.4_2025‑03‑10.proof.json. When everything lines up, audits are boring—in a good way.

At this point, the natural question is: how often should you anchor, and what does that cost versus batching? Is hourly stamping overkill for your team—or surprisingly cheap insurance? Let’s break down real pricing patterns and the gotchas next.

Pricing, limits, and the real costs to expect

Let’s talk money. You’re not just paying for a “stamp”; you’re paying for an audit trail that can stand up in front of a skeptical auditor or an angry competitor. The sticker price is one thing, but the real bill depends on how often you anchor, how you batch, and how your team uses the API.

“The cheapest proof is the one you can win with.”

Free vs paid: what’s included

I’ve seen a common pattern across blockchain timestamping tools like Stampery:

• Free tier: a small number of stamps per month, manual uploads, single user, basic certificates, and access to a web verifier.


• Paid tiers: higher monthly stamp limits, API access, team seats, batch processing, exportable proofs, multiple projects, priority anchoring cadence, and support/SLA.

The big difference isn’t just “more stamps.” It’s automation, governance, and reliability. If you plan to wire this into CI/CD or compliance workflows, assume you’ll graduate to a paid plan quickly.

What impacts your monthly bill

Here’s what actually moves the needle on cost:

• Anchoring frequency: hourly vs daily vs weekly. Faster cadence = more on-chain commits, which vendors price into plans. Priority anchoring (faster publication) often carries a premium.


• Batching (Merkle trees): smart batching compresses thousands of file hashes into a single on-chain anchor. Better batching = lower effective cost per proof.


• API usage: requests per minute/day, webhook retries, and overages if pipelines get noisy.


• Volume of files: raw count matters, but so does how they’re grouped. Ten thousand tiny files can be cheap if batched; a stream of unbatched one-offs is not.


• Projects and governance: more workspaces, audit logs, and role-based access sometimes live on higher tiers.


• Multi-chain anchoring: anchoring to Bitcoin and Ethereum adds redundancy and longevity—and vendors may price accordingly.


• Support/SLA: enterprise response times, legal-ready reports, and dedicated support often live behind higher plans.

One more thing to watch: gas and network volatility. Bitcoin and Ethereum fees swing with demand—vendors typically shield you with fixed pricing, but some reserve the right to apply surcharges during extreme spikes. Historical fee swings aren’t theoretical; check the data:

• Bitcoin average transaction fee trends: bitinfocharts


• Ethereum gas tracker: Etherscan

Hidden or easy-to-miss costs

• Fair use caps: some plans say “unlimited” with reasonable-use limits—hit them and you’ll face throttling or surcharges.


• Overages: per-stamp or per-API-call charges after you cross plan limits.


• Priority anchoring: shorter lag from upload to chain inclusion often costs extra.


• Seats and SSO: more users and enterprise SSO/SAML usually sit on higher tiers.


• Audit log retention: extended retention windows can be a line item.


• Your own storage: timestamping tools anchor hashes, not content. You’ll still pay for document storage (S3, SharePoint, Git, etc.).

Real-world examples you can model

1) Product design team, weekly anchors

• Files: 1,200/month (CAD and PDFs)


• Flow: batched daily, anchored weekly (7 on-chain commits/month)


• Impact: excellent per-proof efficiency; predictable bill; 5–7 day max time-to-proof


• Use when: you need audit-ready trails without near-real-time publication

2) Software team anchoring releases hourly

• Artifacts: 3 build artifacts/hour, 10 hours/day, 20 days/month → 600 artifacts


• Flow: API submits per commit; service batches hourly → ~200 on-chain commits/month


• Impact: higher cost than weekly, but aligns with release integrity and incident timelines


• Tip: anchor commit hashes and artifact manifests, not every file inside the build, to cut volume

3) Replacing traditional notarization

• Docs notarized today: ~25/month


• Typical U.S. notary cost: $5–$15 per signature in person; remote online often $25–$50 each (National Notary Association overview)


• Conservative monthly spend today: $125–$1,250+ depending on method


• Timestamping: a predictable subscription often replaces these one-offs, and you can stamp every iteration, not just finals

A simple way to forecast your cost

Use this quick mental model before you pick a plan:

• Proofs needed per month = files you care about × versions worth proving (not every save)


• Anchors per month = proofs ÷ average batch size × anchoring cadence


• API buffer = expected calls × 1.2 (to cover retries and spikes)


• Plan = pick the tier that covers proofs + API + seats + desired anchoring speed without relying on overages

If you aren’t sure about cadence, anchor slower by default and fast-path only the events that matter (final design, signed contract, release candidate). That hybrid model keeps bills low and compliance tight.

When a free plan is enough

• Side projects and invention notebooks where you stamp weekly or monthly


• Occasional contracts and research snapshots


• Manual workflows with no API or team governance needs

As soon as you want automation, multiple users, or strict anchoring SLAs, you’ll get better value—and fewer headaches—on paid.

One last question before you lock a plan: Do they store your files or just hashes, and which chains do they anchor to? The next section breaks down the privacy model, chain choices, and what that means for long-term verification. Ready to see what’s actually recorded—and what never leaves your device?

Security, privacy, and compliance

“Trust is good. Proof is better.” When reputations, IP, or legal exposure are on the line, I want proofs that stand on their own—no NDAs, no vendor lock-in, no “just believe us.” Here’s exactly how I think about Stampery’s security model, what happens to your data, and how to stay compliant without turning your workflow into a headache.

Do they store my files or just hashes?

The security promise behind Stampery is simple: turn your file into a cryptographic fingerprint (a hash) and anchor that to a public blockchain. Best practice is that only the hash is ever anchored—never your files. That keeps your content private, while still giving you a verifiable timestamp and integrity proof.

What I check in any stamping tool:

• Client-side hashing: Ideally, the browser computes the hash locally so the raw file never leaves your machine. If you want total control, pre-hash files yourself with SHA-256 and only submit the digest.


• No plaintext storage: The service should not store your files by default. Hashes are enough for proof.


• Data minimization: Certificates should contain the digest, chain used, transaction ID, and Merkle path. That’s it.

Real-world tip most people miss: hashes can confirm what a file is without revealing its content—but if someone already suspects the content (say a widely shared PDF), they can hash it themselves and match your proof. If confidentiality matters, protect yourself with a simple commitment scheme:

• Salt your data: Hash “file || secret nonce” instead of the raw file. Keep the nonce safe. When you need to prove it, reveal the nonce to reconstruct the same hash.


• HMAC with a secret: Compute HMAC-SHA256(file, secret) locally, then anchor that. Share the secret only when you need third parties to verify.

Why this matters: the collision resistance of SHA-256 and Keccak-256 is strong (see NIST IR 8202), but privacy isn’t just about math—it’s about who can link a hash to content. Add a secret, and you shut down guessing attacks.

Which blockchains are used and why it matters

Stampery anchors to major public chains like Bitcoin and Ethereum. That choice isn’t cosmetic; it directly impacts security and longevity.

• Bitcoin (SHA-256, Proof-of-Work): Ultra-high immutability and conservative design. You’ll typically wait for ~6 confirmations for practical finality. Great for long-term durability and audit trails.


• Ethereum (Keccak-based, Proof-of-Stake): Faster confirmations and economic finality within minutes post-Merge (see Ethereum docs). Ideal for frequent, near-real-time attestations.


• Multi-chain redundancy: Anchoring to more than one chain gives you independent verification paths. If one network suffers congestion or extreme fees, your proofs still stand on the other.


• Merkle batching: Your digest is placed into a Merkle tree with many others; the root is what’s anchored on-chain. This reduces fees and improves throughput without weakening your individual proof.

Bottom line: if you care about durability and public verifiability, Bitcoin and Ethereum are the most battle-tested foundations you can pick today.

Legal and compliance considerations

Is a blockchain timestamp “legal”? In most places, it’s treated as technical evidence—you’re proving existence and integrity at or before a given time. Courts don’t certify the blockchain; they evaluate the process and the credibility.

• US (Rule 901): The Federal Rules of Evidence allow authentication by showing a process produces accurate results (see FRE 901(b)(9)). A well-documented stamping workflow fits neatly here.


• EU (eIDAS): Qualified electronic timestamps have special status under eIDAS. Blockchain timestamps aren’t automatically “qualified” unless issued by a Qualified Trust Service Provider—but they’re still admissible technical evidence.


• State-level recognition: Some jurisdictions explicitly acknowledge blockchain records (e.g., Vermont’s 12 V.S.A. § 1913; link).

For regulated teams (finance, health, public sector), I run a simple blueprint that satisfies auditors without slowing the business:

• Chain-of-custody: Keep the original file, the hash, and the certificate together in a durable repository with versioning.


• Policy + SOPs: Write down when and how you stamp, how you verify, and who’s responsible. Consistency beats heroics.


• Sign + stamp: Pair e-signatures for authorship with blockchain timestamps for existence and integrity. It’s a powerful combo.


• Independent verification: Prove you can verify without the vendor. Auditors love independence.

Privacy regulations matter too. A hash of personal data can still be considered pseudonymous data (not anonymous) under GDPR—context is king. The UK ICO explains this nuance well. Practical playbook:

• Don’t anchor PII; anchor hashes only.


• Use salt/HMAC for sensitive material to prevent guessability.


• Store personal data off-chain in systems with retention controls and access logs. The blockchain holds only proofs.

And yes—NIST’s guidance on timestamping and signature timeliness is a good north star for policy folks (NIST SP 800-102).

What happens if the service goes offline?

This is the make-or-break question. The right answer is: your proofs still work. That’s the whole point of anchoring to public blockchains.

How I future-proof my proofs:

• Export certificates for each stamped item (hash, chain, txid, Merkle path). Keep them in your own storage with backups.


• Note the transaction IDs on Bitcoin and/or Ethereum. These are your anchors; explorers can find them decades from now.


• Verify independently using open tools (e.g., OpenTimestamps for OTS-style proofs; generic blockchain explorers for tx inclusion). You’re checking that your hash is included in the on-chain root via the Merkle path.


• Document the verification steps for an auditor or judge: hash → Merkle path → transaction → on-chain root. Clear, boring, undeniable.

Security hygiene still matters. Even with perfect cryptography, sloppy ops can ruin your day:

• Protect API keys with rotation, scoping, and IP allowlists where possible (see OWASP secrets management).


• Enable MFA for every account with access to proofs or stamping permissions.


• Automate logs so you can prove who stamped what, when, and from where.

Security is a process, not a product. — Bruce Schneier

One last thought: if a vendor’s marketing screams “we’re the source of truth,” I run. The blockchain should be your source of truth. The vendor is just a fast lane to get you there.

Curious where this approach shines and where it can bite you? I’m about to break down the real pros, cons, and the best alternatives—want the brutally honest version or the glossy brochure?

Pros, cons, and best alternatives

Where Stampery shines

Here’s where this kind of blockchain timestamping really earns its keep in my world.

• Proofs that don’t leak content. You stamp a hash, not the file itself. That means you can prove a document existed at a specific time without revealing what’s inside. For IP-heavy work (product designs, research notes, pre-release code), that’s gold.


• Public-chain anchoring. Anchoring to Bitcoin and/or Ethereum gives you a proof that’s verifiable outside any vendor. If you’ve ever worried about “what if the company disappears?”, this model calms that anxiety.


• Batching and auditability. Merkle aggregation keeps costs down at scale and creates a tidy audit trail. I’ve watched teams use this on release days: they stamp the release bundle, tag the commit, and attach the certificate to the changelog. Future audits become boring (which is exactly what you want).


• Low friction for teams. With an API-first approach, you can bake stamping into CI/CD, issue management, and logging. One practical example I’ve seen: a security team automatically stamps critical log checkpoints during incidents, then includes the proof IDs in the incident postmortem.

“Trust math, not memory.” Stamping makes that a daily habit, not a special event.

On risk and robustness: modern hashes like SHA-256 have no known practical collisions for real-world use, and blockchain confirmations create a time anchor that’s hard to dispute. Courts in multiple jurisdictions have accepted blockchain-based evidence to establish existence and integrity, and electronic timestamps are explicitly recognized under frameworks like eIDAS in the EU. You still need process discipline (who stamped what, and why), but the technical foundation is solid.

Potential drawbacks

• Costs at high volume. If you stamp every tiny file separately or anchor too frequently, the bill can creep up. Batching and rules help, but ops teams should watch cadence and API usage.


• Latency vs. certainty trade-off. Faster anchoring means higher cost; slower batching means you might wait longer for an on-chain confirmation. Most teams are fine with minutes to a few hours, but if you need instant notarization-style confirmation, plan for it.


• UX and vendor support matter. The crypto plumbing is powerful, but if your team can’t navigate the dashboard, exports, or API docs, you’ll feel it. Evaluate support SLAs if this will touch audits or legal disputes.


• Jurisdiction questions. It’s strong technical evidence, but the legal weight can vary. In the EU, pairing with qualified electronic timestamps helps for regulated use. In the US, evidence rules are friendly to this kind of proof, but local expectations differ. When in doubt, pair with e-signatures or notarial steps.


• Process gaps are still on you. A perfect timestamp won’t save a messy chain-of-custody. Define who stamps, when, and how proofs are stored and referenced. I keep a simple SOP: file → hash → stamp → store certificate → reference ID in the related ticket or document.


• Privacy hygiene. Always check whether you’re uploading a file or only its hash. For sensitive data, hash locally first and only send the digest. It’s a tiny step that avoids headaches.

Alternatives and how they compare

• OpenTimestamps (open source, DIY)
  Best for: developers who want full control and minimal cost.
  What I like: anchors to Bitcoin, vendor-neutral proofs, no subscription.
  Trade-offs: no hosted UI, fewer team features, you manage scheduling, storage, and verification UX yourself. Great for power users and automated pipelines.


• OriginStamp / Woleet (SaaS alternatives)
  Best for: teams that want a hosted experience, APIs, and reporting.
  What I like: similar trust model (hash anchoring), enterprise options, integrations.
  Trade-offs: pricing and cadence rules vary; make sure export/verification formats are open and easy to check independently.


• Guardtime KSI (enterprise timestamping)
  Best for: large organizations needing high-throughput, compliance-heavy environments.
  What I like: battle-tested at national and telco scale.
  Trade-offs: procurement and integration overhead; often overkill for startups or small teams.


• e-Signature suites with trusted timestamps (DocuSign, Adobe)
  Best for: contracts and workflows where signatures are primary and timestamps are a bonus.
  What I like: strong legal recognition, especially with qualified timestamps in the EU.
  Trade-offs: not public-chain anchored by default; you’ll pay for the signature stack, not just timestamping.


• Traditional notarization (in-person or online)
  Best for: narrow cases where a notary’s formal act is required by law or policy.
  What I like: universally understood in legal settings.
  Trade-offs: slower, per-document costs add up, and it doesn’t prove content integrity the way hashing does unless you package both.

If you’re comparing, ask yourself three simple questions:

• Where will this proof be used? Internal audits vs. litigation vs. sharing with partners.


• What’s my volume and cadence? High-frequency stamping pushes you toward APIs, batching, and transparent pricing.


• Who needs to verify and when? If the answer is “anyone, years from now,” public-chain anchoring and open verification formats are non-negotiable.

When to pick what

• Solo creators and startups: a SaaS stamper is fast, affordable, and easy to explain to clients. Stamp drafts, design iterations, and release builds; keep certificates with your project files.


• Developer teams: integrate via API in CI/CD. Stamp release artifacts, SBOMs, and log checkpoints. Add the proof ID to your changelog or release notes.


• Heavily regulated orgs: combine blockchain stamping with e-signatures, document management, and a written SOP. Map it to your control framework (ISO 27001, SOC 2). Your auditors will thank you.


• Legal-heavy workflows: use stamping for existence/integrity, and layer traditional notarization only where the statute actually demands it. You’ll save time and money without compromising evidentiary strength.

Curious how courts look at these proofs, whether there’s a free plan worth using, and what happens if the service ever shuts down? I’ve got quick, straight answers to those next—want the short version or the in-the-weeds version?

FAQ and final verdict

Is Stampery legal and recognized?

Short answer: it gives you strong, technical evidence that often stands up when what you need to show is “this exact data existed by this time and hasn’t changed.” Courts typically care about method and integrity, not brand names.

• In the EU, eIDAS recognizes electronic timestamps as evidence; blockchain stamps aren’t automatically “qualified” timestamps, but they’re still admissible as proof of integrity and time when presented with proper context.


• In the U.S., FRE 901 focuses on authenticating evidence by showing how it was produced. Hashes + public blockchain anchoring fit naturally into 901(b)(9)’s “evidence about a process or system.”


• Several states explicitly nod to blockchain records (e.g., Vermont 12 V.S.A. § 1913; Arizona HB 2417).


• NIST’s guidance on trusted timestamps (SP 800-102) outlines the security model that hash-and-anchor workflows follow.

Real-world note: I’ve seen blockchain-anchored proofs used in IP skirmishes (design drafts), software release audits, and vendor disputes. The key is chain-of-custody: hash the file, anchor, and keep your certificate and original file safe. If your jurisdiction demands a specific kind of timestamp (e.g., qualified eIDAS), pair this with e-signatures or a qualified timestamp service.

Is there a free plan, and what are the limits?

Expect a starter tier that lets you stamp a limited number of files per month and then paid plans for higher volume and API access. Limits typically show up as:

• Monthly proof caps (e.g., a few dozen on free)


• Anchoring cadence (instant vs. batched)


• API rate limits and team seats

Before you commit, check the current pricing page and map it to your real workload. As a thumb rule, teams that stamp every build, every commit, and key documents should model the monthly volume. For example, 20 document proofs + 80 CI stamps + 10 incident logs = 110 anchors/month. If your plan batches multiple hashes into one on-chain transaction, your per-proof cost often stays friendly.

What if Stampery shuts down or changes plans?

Your proofs are still valid because the anchors live on public blockchains. The safety net is in your backups.

• Keep your receipts: Save the proof files/certificates (JSON/PDF), the file’s hash, Merkle path, algorithm, chain, and the TXID. Store them in at least two places (cloud + offline).


• Export regularly: I set a monthly reminder to export proofs for the prior month and drop them into a versioned archive.


• Document the process: A one-page SOP with “how we hash, how we anchor, where we store proofs” makes later validation painless.


• Redundancy helps: If the tool lets you anchor to more than one chain, use it. Independent verification paths reduce risk.

Simple mantra: Hash first. Anchor second. Back up always.

How do I verify a proof without the website?

Here’s the quick, tool-agnostic path you can follow years from now:

• Re-hash your file: Use a standard tool to compute the hash (e.g., SHA-256). On macOS/Linux: shasum -a 256 yourfile.pdf. On Windows: CertUtil -hashfile yourfile.pdf SHA256.


• Match the hash: Compare the output to the hash in your proof. They must match exactly.


• Check the Merkle path: If your proof includes a Merkle path, recompute the root using your hash and the path nodes. The result should equal the on-chain root recorded by the transaction.


• Confirm the transaction: Look up the TXID on a reliable explorer (e.g., a Bitcoin or Ethereum explorer). Verify the block number, timestamp, and the embedded root or commitment.


• Record the timestamp: The earliest credible time is the block’s timestamp. For strict audits, note the block height and explorer URL in your report.

If your certificate follows an established format (for example, OpenTimestamps for Bitcoin), you can use compatible open-source verifiers. The big win here is independence: you’re not stuck waiting on any single vendor.

Conclusion and next steps

If you need quick, repeatable proof-of-existence and integrity, this approach delivers. It’s not a silver bullet for every legal setting, but for product docs, source releases, contracts, lab notes, and security logs, it’s hard to beat the cost-to-assurance ratio.

My suggestion:

• Run a 30-day pilot across one workflow (e.g., contract finals or release artifacts)


• Verify a few stamps independently and write down the steps


• Automate the wins (CI, DMS hooks, or simple scripts)


• Back up proofs in two places and review monthly

I’ll keep tracking updates, pricing shifts, and best alternatives on Cryptolinks. If you want new picks, practical setups, and real comparison tests, check back—there’s always something worth trying in this space.