Open Contracting Data Standard (OCDS)

The Open Contracting Data Standard (OCDS) is the most widely adopted international specification for publishing public procurement data in a structured, open format. Developed and maintained by the Open Contracting Partnership, it enables governments, civil society, researchers, and businesses to access and analyse contracting information in a consistent way regardless of which country or platform produced it.

What is the Open Contracting Data Standard (OCDS)?

OCDS defines a common JSON-based schema for describing every stage of a public contracting process. A single procurement, from initial budget planning to final contract implementation, is represented as a collection of OCDS releases that are merged into an OCDS record. Each release documents what happened at a particular point in time, and the record aggregates those releases into a complete picture.

The standard organises procurement information into five lifecycle stages:

1. Planning: budget allocation, needs assessment, and early market engagement.
2. Tender: publication of the opportunity, receipt of bids, and clarification rounds.
3. Award: evaluation outcome and announcement of the winning supplier.
4. Contract: signed agreement terms, amendments, and milestone schedules.
5. Implementation: delivery progress, payments, and performance outcomes.

OCDS uses a set of standardised codelists (for currency, procurement method, award status, and so on) and allows governments to extend the core schema through OCDS extensions when local legal requirements demand additional fields.

Across Europe, OCDS adoption is growing. The European Commission's TED (Tenders Electronic Daily) portal, which publishes contract notices and award notices under the EU procurement directives, has published OCDS-compatible data feeds. Several EU member states and Ukraine have adopted OCDS as their primary open contracting format, and the UK's Find a Tender service publishes data that maps to OCDS concepts.

Why OCDS matters for bidders

For suppliers competing for European public contracts, OCDS data unlocks capabilities that raw PDF notices cannot. Because OCDS is machine-readable and consistently structured, platforms can ingest it to power opportunity search, award history analysis, incumbent identification, and price benchmarking. When a publisher releases high-quality OCDS data, a bidder can trace a buyer's historic contract awards, understand typical contract durations and values, and identify which competitors have won in a given category.

Understanding what OCDS is also helps bidders interpret platform data: fields labelled "tender stage," "award stage," or "implementation milestone" in procurement intelligence tools map directly to the OCDS lifecycle. If a platform shows incomplete data for a tender, the likely cause is that the publishing authority has not yet issued releases for later stages.

Example

A Romanian municipality publishes an OCDS record for a road maintenance contract. The record contains a planning release (budget approved), a tender release (notice published on TED), an award release (winning bidder named with contract value), and a contract release (signed agreement uploaded). An infrastructure company monitoring Romanian procurement can use OCDS data to build a complete picture of the municipality's spending patterns without manually reading dozens of PDF documents.

Frequently Asked Questions

Is OCDS mandatory in Europe?

OCDS is not yet legally mandated across the European Union, though several member states and candidate countries have adopted it voluntarily or as part of anti-corruption reform programmes. The EU Open Data Directive and the push for machine-readable procurement data are increasing alignment with OCDS principles, and TED publishes OCDS-compatible feeds. The UK government similarly publishes open contracting data through the Find a Tender service.

How does OCDS relate to EU procurement directives?

OCDS is a data publication standard, not a legal framework. Directive 2014/24/EU, Directive 2014/25/EU, and the UK Procurement Act 2023 govern what buyers must do and publish. OCDS defines the format in which that published information is structured. The two layers are complementary: the directives mandate transparency; OCDS makes that transparency machine-readable and internationally comparable.

Can I access OCDS data for free?

Yes. OCDS data is open data by design. Publishers release it under open licences, and the Open Contracting Partnership maintains a registry of known publishers. Aggregators such as the Open Contracting Data Explorer consolidate data from multiple countries into a single interface.