Data standard for public procurement – Open Contracting

New to data standards? Please read these introductions.

About Open Contracting Data Standard

The Open Contracting Data Standard (OCDS) was created “to provide shareable, reusable, machine-readable open data on public contracting across the entire cycle of public procurement.”

Publishing contracting data benefits governments, businesses and society as a whole. As stated on the Open Contracting Partnership website, it can help stakeholders:

  • deliver better value for money for governments,
  • create fairer competition and a level playing field for business, especially smaller firms,
  • drive higher-quality goods, works, and services for citizens,
  • prevent fraud and corruption,
  • promote smarter analysis and better solutions for public problems.

As Open Contracting Partnership (OCP), the entity behind the standard, has excellent documentation of the procurement process, data standard, use cases and impact of  openness online, I will quote it extensively to provide a general overview.

What kind of data is covered?

If you’re not familiar with the contracting process, the OCP has a great short guide on the contracting process. It starts with a summary of what data is covered:

 ocds_green_planning-svg  ocds_green_tendering-svg  ocds_green_awarded-svg  ocds_green_signed-svg  ocds_green_implementation-svg
Planning Initiation (Tender) Award Contract Implementation
Project plans
Procurement plans
Market studies
Public hearing info
Tender notices
Line items
Details of award
Bidder information
Bid evaluation
Final details
Signed contract
Progress updates
Completion or Termination info

Value of standardization and linked data

Information on the procurement processes is inherently connected to other types of data such as: budget lines within which tenders are made, procuring agencies and buyers on the one side and suppliers on the other and contracts. OCDS takes the approach of providing both machine-readable data that can be cross-referenced with data stored in other standards, as well as human-readable descriptions that can be used on their own.

The example below presents a functional classification for the contracted item. It contains everything: a human readable description, an unique ID within the given scheme of European Union Common Procurement Vocabulary (CPV) and a URI which  points to the detailed information of the related CPV code.
    “description”: “Cycle path construction work”,
    “id”: “45233162-2”,
    “scheme”: “CPV”,
    “uri”: “”

OCDS data can be linked to data in other repositories that use known standards and specifications. Budget lines can link to data in Fiscal Data Package, procuring agencies can link to Popolo-standardized datasets, suppliers and commercial procurers can link to OpenCorporates datasets. The more connections one includes, the easier it is to navigate and analyze the data.

Who uses the standard? Where to find the data?

The power of the standard comes from the power of all the stakeholders using it. So who uses OCDS?

The Open Contracting Partnership keeps a crowd-sourced database of all efforts to open and analyze procurement processes worldwide. In the CEE region, there are a handful of initiatives which have already started to or have already incorporated the Open Contracting Data Standard.

The highlight of the civil society efforts is the Ukrainian ProZorro e-procurement system. Started by activists, ProZorro quickly gained the support of multiple commercial procurement platforms, as well as the institutional support of Transparency International Ukraine. First implementations have resulted in greater transparency and reduced costs. Talks about transferring the system from a non-profit to the government body have begun, and have resulted in commitments, bills and a four-month process of security and-stress-testing the system to handle the load of a country-wide implementation. Since August 1st, 2016, ProZorro has became an obligatory system for  publishing of all tenders above 200,000 UAH for goods and services and 1,500,000 UAH for infrastructure projects nationwide. Over the last year e-procurement in Ukraine grew from 3 separate commercial platforms to 10 platforms synchronised via ProZorro’s central database.

The Open Contracting Partnership highlights this case in Why Open Contracting:
“In Ukraine, government, business, and civil society have already built a world class, transparent procurement system called ProZorro to rebuild trust with both citizens and local businesses. ProZorro has now run over 26,000 tenders for $240 million in goods. Apart from doing this fully openly and fairly, it has helped save an average of 13% on budgeted spending too. New businesses participate in the procurement process and win contracts. This early impact has led to principles of open contracting including open data and citizen monitoring being enshrined in a new procurement law. ProZorro, despite the ongoing governance challenges in the Ukraine, is now being scaled up across government.”

Apart from ProZorro there are several other civil society projects dealing with procurement, but at  the time of writing (2016-07-29), it was the only project to use OCDS.

All civil society efforts in this area are advocating OCDS-compliant data publication by governments. Some of the authorities in CEE which have adopted these recommendations include:

  • Digital Agenda Agency of Romania has pledged to adopt OCDS, but they are behind the defined schedule;
  • Moldovan Open Contracting portal published limited information (contract awards) in OCDS;
  • the Ukrainian government has adopted the ProZorro platform creating an official OCDS datasource.

Up-to-date list of the OCDS implementions worldwide can be found on

How to open up the data?

The go-to guide for  opening the data is the comprehensive OCDS online documentation. The Getting Started section will lead you through the process, starting from discussing use cases, through mapping the terminology, to the validation of published data.

One interesting resource that is not [yet] linked in the documentation is the “Localising OCDS: translations, terminology and extensions” blog post. It focuses on the mapping of the terminology from a given legal framework to OCDS (which is one of the harder steps in opening up the data). The blog post’s authors propose using a dedicated Mapping Spreadsheet. In my experience, it is a tool which can serve as the necessary bridge between legal experts and developers, and one which I highly recommend.

In the end, if you are stuck or want to consult your data opening efforts (please do!), you can contact Open Contracting Partnership helpdesk and the wider OCDS community for support.

Data bulks & API

The Data files, APIs and discovery section of the documentation provides recommendations on how to publish the data. Several methods are proposed, each comes with an explanation about optimal use scenarios.

As for the API for OCDS data, the standard is still emerging. In January 2016, a discussion on the standardization of the API for OCDS data began between the OCP and organizations that have created APIs on their own. Now, a separate repository serves as the basis for the Open Contracting Data Standard API specification: Working Draft. A blog post from June elaborates the different approaches to designing the API. Do you need an API? Then join the discussion.

The ProZorro platform serves data structured similarly to OCDS through a publicly documented API. Check a list of all tender IDs, append ID to list’s URL to get details on a given tender. There is an ongoing effort to implement full OCDS compatibility.

Which tools can process OCDS data?

There are several open source tools for processing or producing OCDS standardized data. They are dynamically developed, as both them and the OCDS standard are quite young initiatives. I will present a few examples suggested by the OCP team. Up-to-date list of the OCDS implementions worldwide can be found on

Design of the Vietnamese platform; source:

Design of the Vietnamese platform; source:

In Vietnam, non-profit Development Gateway is working with Government of Vietnam’s Public Procurement Agency (PPA) to turn procurement data from Excel files into OCDS-compliant data. This open source tool offering OCDS data export and a publicly available dashboard will be launched in the fall of 2016. Read the whole story of implementing open contracting in Vietnam on DG’s blog.



In Nigeria, the Budeshi platform is being used to carry out advocacy to public institutions seeking adoption of open contracting processes. Technically it is a simple dashboard providing some visualizations and presenting the underlying data in its raw form. Read more about this website.


Homepage of Contrataciones Abiertas website -

Homepage of Contrataciones Abiertas website –


Mexico City runs Contrataciones Abiertas website where it shares all of their procurement processes in a searchable dashboard and API serving OCDS data. BTW, government of Mexico is tagging all ocds-compliant datasets on their data portal.

Contract details on Contrataciones Abiertas website -

Contract details on Contrataciones Abiertas website –


In CEE region, the Open Procurement, a technological platform behind the ProZorro initiative is the closest to fully utilizing OCDS data on a larger scale – once full OCDS compatibility will be implemented. It is a central database of procurement processes to which end-users (procuring agencies, suppliers and other visitors) can connect through commercial web platforms that implement e-Procurement system features.

How to contribute to the standard?

All discussion about the standard take place openly in the standard’s Github repository. Open Contracting Partnership curates the standard development.

Questions concerning data modelling in specific cases and discussions about extensions are to be placed in the standard’s repository or directly to the OCDS help-desk or on a mailing list for less experienced users.


Several people has provided me with valuable input for this article. I would like to thank Duncan Dewhurst and Georg Neumann from the Open Contracting Partnership, and Yuriy Bugay, Myroslav Opyr and Andriy Kucherenko from the ProZorro initative.