Frequently Asked Questions

You’ve Got Questions. We’ve Got Answers.

What is Holiday Oracle?

Holiday Oracle is a machine learning based holiday date prediction service which uses open data from open data projects and open source software projects to generate consensus holiday rules and date predictions. It may be consumed as a RESTful API or a Smart Contract Oracle.

Off Chain Data’s Holiday Oracle uses open data from open data projects and/or open source software projects. Projects currently used:

Date Holidays ISC License
Charlie HR MIT License
Enrico MIT License
Flagday MIT License
Nager MIT License
Python Holidays MIT License
Workalendar MIT License
Yasumi MIT License

We thank the open projects for making their software code available.
We may change the projects which are used in Holiday Oracle in the future and are currently assessing various sources of open data to determine how they may be used in Holiday Oracle in the future.

The projects listed above, and any other projects used in the future, are not associated with Off Chain Data, nor do they endorse or attest to the results of Off Chain Data’s Holiday Oracle.

Off Chain Data is supportive of the efforts of the open data and software communities and will make donations, grants and report issues to projects. Off Chain Data does not, however, control any of these projects.

An open data or open source software project might be a great option for your use case, and we encourage you to check out the projects listed above, as well as the many others out there. You might consider Holiday Oracle for your project if:

  1. You haven’t the time, skills or inclination to assess the holiday dates generated by the open data or open source software projects in order to select just one
  2. The open source software project in your preferred programming language doesn’t support the countries or subdivisions your software project needs
  3. You don't want to maintain code, and instead prefer to consume holiday dates via an API
  4. You need control over the holidays that your App or dApp uses (through adjusting the consensus score)
  5. Your dApp or smart contract needs the trustless approach of a consensus based date oracle

Yes, there is a subscription fee to access Off Chain Data’s Holiday Oracle as an API or via Smart Contract Oracle.

We decided to release Holiday Oracle as a commercial service, and to share our success with the open data and/or open source software projects which the Holiday Oracle system uses. Our pledge is to donate 15% of our revenue (excluding any sales, goods/services or value added taxes or charges which may be applicable) from the licensing of Holiday Oracle with open data and/or open source software projects used in the Holiday Oracle system. We hope our contributions will enable open data moderators and open source software developers to maintain and improve existing projects, and possibly also kickstart new ones.
We also plan to make grants for new projects and datasets. If there are particular holiday dates that your App or dApp needs that aren't currently supported, please contact us so we can consider your use case(s) when deciding future grants. We are keen to support the growth of the open data community.

Three ways:

  1. Donations to help them maintain existing projects
  2. Grants to kickstart the establishment of new projects
  3. Feedback from us and our users about date errors and omissions

We’ve made ad hoc monetary donations and grants, and our pledge is to share 15% of our revenue from the licensing of Holiday Oracle with open data and open source software projects.

We are also committed to report bugs and improvements to the open data and open source software projects so that they may continually improve. If you spot an error, please let us know.

We periodically search for new sources of open date data, and automatically pull updates from our existing sources. Whenever we locate an update, Off Chain Data’s Holiday Oracle will automatically re-generate new holiday rules and date predictions, and push these via the API or Smart Contract Oracle.

Test us before you sign-up - you may access all of our 2019 date predictions here to test if they are suitable for your software project or use case.

You may also cancel your subscription any time in the first 30 days for a full money back guarantee. is owned by Off Chain Data, a Sydney based business passionate about technology and data driven change. Read more about us here.

It’s easy to access Holiday Oracle via our API - click here to access the Off Chain Data API documentation.

Our license agreement is accessible here. You will need to accept this to use the Holiday Oracle service.