Discover the product, its API and read the FAQ

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Woleet is a data anchoring and signing platform. This service is accessible in several ways:

With the web application the user can directly manage his own anchors and edit their metadata manually, with the API, applications can integrate the data anchoring feature without friction.

User Manual

The Dashboard

What you can see in your Dashboard:

  • Your remaining credits
  • Your anchor list in a sortable table

What you can do with the Dashboard:

  • Search for anchors by name
  • Search for anchors by tags
  • Edit your anchors if necessary
  • Download your anchoring receipts (once the transaction is confirmed).

Data Anchoring

The anchor creation process is very simple. You just have to select or drag and drop the file you want to anchor and fill additional information if needed (metadata). Metadata will be printed when the anchor will be verified.

Step 1: File(s) selection
You can select files either by clicking on the dropzone or by dragging and dropping the files on the zone.

Step 2: Hash calculation
Once the file selected the brower will calculate its hash and create an anchor. To discover the details of the anchor or edit its properties, click on the green bar. Note that the file is not uploaded on our severs and stay under your entire control.

Step 3 (Optional): Add metadata
You can add as many metadata as you want to your anchors. You just need to add a list of key/value that will be added in the anchoring receipt and displayed when the file will be verified. To do so, enter key name (only with letters and digits with no spaces), click on the plus button (+) . Then you can enter the value corresponding to that key. You can also delete metadata by clicking on the minus button (-).

In this screen you can see:

  • The name of the anchor (name of the file by default, but you can change it)
  • The hash of the file linked to this anchor
  • The tags of the anchor
  • The metadata of the anchor (by default the size and type of the file)

Step 4: Validation
To validate the creation of your anchors, click on the « Create anchors » button. A validation message is displayed to confirm the creation of your anchors: note that it can take up to 24H before your anchors are written in the blockchain.

Anchor verification

In order to verify that a file is anchored in the blockchain, you need to file itself and optionally the anchoring receipt (in case anchoring was not processed by Woleet but by another provider).

A this step you cannot make any modification, it's just about verification.

Verify a file

« Verify a file » allows you to check whether a file had been anchored in the blockchain, and get the anchoring date.

You just have to drag and drop the file in the drop zone or click in the zone to choose the file.

Anchoring information about the file is printed:

  • The name of the anchor
  • The hash of the file anchored
  • Anchor tags
  • Anchor metadata
  • Hash or the file (must be identical with the anchor hash)
  • The date of the block containing the transaction used to anchor the file
  • The anchoring receipt and a download link

Verif y a Chainpoint receipt

You have the possibility to verify a Chainpoint anchoring receipt recorded in the blockchain by another compatible service.

To do so, drag and drop the file and associated receipt on the dedicated drop zones (you can also click on the zones to choose the file and the receipt).


What is data anchoring

Data anchoring on the blockchain consists in using the properties of resilience and immutability of the Bitcoin blockchain to link any piece of data to a public and tamper resistant ledger. This process builds a strong crytographic link between a timestamped transaction and data, proving that data had not been modified since the transaction's confirmation date. The proof given in return (the anchoring receipt) cand be verified without any third party by anyone possessing the data and the corresponding receipt.

What is an anchoring receipt?

An anchoring receipt is a JSON file containing all information required to verify the validity of an anchoring process. It is important to store the anchoring receipt with the anchored data, both being mandatory for verification.

What data anchoring is useful for?

There are many se cases for data anchoring: from certification to authentication, proof of existence, traceability, every use case where the date needs to be proven.

Are my data readable by Woleet?

Woleet only access to the hash of the data, not the data itself. The hash is calculated on client side and never uploaded to our servers. It is impossible to build back the data from a hash. Our client keep the content of their data safe.

What is the purpose of metadata?

Metadata enrich the anchoring receipt. They give some additional information, not contained in the data itself but are not mandatory for verification. Metada are useful for readability when the anchoring is verified.

What happens if I lose anchored data?

If you lose the anchored data, it will be impossible to prove the anchoring process. It's therefore very important to carefully save the anchored data.

What happens if I lose the anchoring receipt?

Don't panic! Woleet can generate any receipt for a data anchored by the platform as we keep the useful information to rebuild the receipt if needed. You can ask for a receipt via our web interface or our API.

What is the legal value of data anchoring in blockchain?

Data anchoring in blockchain has no clear legal value yet, but multiple initiatives are taken all around the world to give a legal recognition to blockchain proofs. Data anchoring on blockchain is regardless a totally safe mathematical proof and by anchoring your data now, you can be sure that il will be valid by the time each country legislation is ready for it, either by law or by jurisprudence.

What is the average delay for data anchoring?

The average delay for data anchoring depends on the type of contract you sign with Woleet. By default the average time for anchoring is 24 hours, but it's possible to get your data verified in one hour at best.

What happens to my anchors if Woleet disappears?

The proof format used by Woleet is open and interoperable: an anchoring receipt made by Woleet is verifiable by anyone with an internet access and tools compatible with this format.

How do I share a data anchoring proof?

You just have to share the anchoring receipt and the data to verify. The recipient will be able to use any compatible tool to verify this operation.

Which blockchain is used for anchoring?

For its security, its immutability and its open architecture, Woleet has chosen the Bitcoin blockchain for data anchoring. This choice is based on our will to base on the safest infrastructure available out there, battled tested and resilient with the highest level of security.

What is Bitcoin?

Bitcoin is a currency, a network and a protocol. Woleet uses Bitcoin as a commodity useful to share an internationaly verifiable timestamped truth.

Why not using Ethereum or other blockchains?

As we want a digital tamper-resistant digital proof, a certain degree of robustness and global security is mandatory. The security model is crucial because we need an immutable and censor-resistant ledger. Ethereum or other blockchain solutions implement other security models not suitable for the use cases offered by Woleet. Moreover, those blockchain solutions are not mature enough to consider using them in production.

Is Bitcoin secured?

Bitcoin has almost 8 years of research and development in multiple domains like cryptogrpahy, distributed computing and have seen important investment in its infrastructure globally. The maturity of Bitcoin ecosystem gives the opportunity to deploy applications in production. The decentralized model of Bitcoin moves the responsability of securing the bitcoins to the end user, by using woleet the user does not have to bother about buying or secure their own bitcoin as Woleet uses its own bitcoin and is in charge of their security.

Are bitcoin transaction reversible?

Bitcoin transaction are not reversible. Once confirmed by the network a bitcoin transaction cannot be modified or reversed. This is a crucial feature in the Bitcoin protocol and this is why Bitcoin has value.

What is the proof format used by Woleet?

The proof format used by Woleet is Chainpoint 1.1. Chainpoint 2.0 will be supported soon.

Is Woleet a trust third party?

No. Woleet is a middleware platform simplifying acces to the Bitcoin blockchain for specific use cases.


The Woleet API is a REST API specified with the Swagger/OpenAPI standard. You can therefore use the specification file to generate the client code for most programming languages by using the Swagger Editor or the Swagger Codegen tool.
In order to help you to integrate your applications, the API documentation is actionable: you can authentify, test API calls (and see their CURL equivalent) and see the results.