Understanding OCDS: The Open Contracting Data Standard Explained

What is OCDS

The Open Contracting Data Standard (OCDS) is an open, non-proprietary JSON schema for publishing structured data about the entire contracting process — from planning to tender to award to contract execution. Developed by the Open Contracting Partnership (OCP), a global non-profit, OCDS was first released in 2014 and is now used by 50+ countries and international institutions to publish public procurement data in a consistent, machine-readable format.

The core idea is stage-based: every procurement is a "contracting process" that moves through defined stages (planning, tender, award, contract, implementation), and OCDS captures the data emitted at each stage. Instead of every country inventing its own format, OCDS gives a common vocabulary so procurement data becomes globally comparable — an Estonian award notice and a Colombian award notice can be analyzed side-by-side by the same tool.

The OCDS release model

OCDS publishes data as time-stamped "releases" keyed by an OCID (Open Contracting ID). Each release contains a snapshot of everything known about the contracting process at that point in time — parties, tender terms, awards, contracts. A single contracting process typically has multiple releases as it moves through stages:

• Planning release — budget allocated, project defined.
• Tender release — RFP published, criteria known, deadline set.
• Award release — winner selected, price known.
• Contract release — contract signed, terms attached.
• Implementation release — deliverables, payments, modifications logged over time.

Publishers can either post individual releases (immutable snapshots) or maintain a "record" — a compiled current-state view merging all releases for one process. Most implementations do both.

Who publishes OCDS

Government adopters (partial list, adopters grow annually):

• UK — Contracts Finder and FTS publish OCDS extracts.
• Ukraine (ProZorro) — the flagship OCDS implementation; every ProZorro tender is OCDS-compliant.
• Colombia (SECOP II) — full OCDS publication across national government.
• Paraguay, Honduras, Mexico — Latin American open contracting leaders.
• Moldova, Georgia, Kyrgyzstan — Eastern European adoption via OCP capacity building.
• Slovakia, Estonia, Portugal — EU member states with strong open-data mandates.

International: World Bank publishes some project data in OCDS-compatible format. Multilateral development banks including EBRD and IDB are progressively adopting.

Why OCDS matters for buyers

Buyers gain analytical capability that pre-OCDS was locked in PDFs:

• Price benchmarking — see what similar contracts cost across regions.
• Supplier concentration analysis — identify categories dominated by one vendor.
• Red flag detection — algorithms can flag single-bid outcomes, short deadlines, suspicious splitting into sub-thresholds.
• Contract lifecycle tracking — modification frequency, cost overruns, delivery delays surface systematically.

Why OCDS matters for suppliers

Even more transformative for the supplier side:

• Market intelligence at scale. You can query the entire contract history of a buyer, category, or CPV code — who won, at what value, on what terms.
• Incumbency tracking. See when contracts are due to expire and be recompeted.
• Pricing calibration. Historical award values in your category tell you what the buyer's willing to pay.
• Machine ingest. Structured JSON means procurement notices flow directly into supplier CRM, bid-tracking, or (as with TenderYeti) AI relevance scoring engines without brittle PDF-scraping.

The core schema (simplified)

An OCDS release has a top-level shape roughly like:

• ocid — unique ID for the contracting process
• date — timestamp of this release
• tag — stage (planning / tender / award / contract / implementation)
• parties[] — buyers, tenderers, suppliers with role tags
• tender — title, description, procurement method, items, dates, criteria, deadline
• awards[] — winners with value, date, suppliers, related lots
• contracts[] — signed contracts, milestones, modifications, transactions
• planning — budget, project rationale

Codelist enums for procurement methods (open / selective / limited / direct), award criteria (priceOnly / costOptimal / bestProposal / ratedCriteria), tender status (planning / active / cancelled / unsuccessful / complete / withdrawn), etc.

Extensions

The OCDS core covers ~80% of what most publishers need; the rest happens via extensions — modular add-ons that publishers can opt in to. Common ones:

• Bid statistics — number of bidders per lot.
• Enquiries — Q&A during the tender period.
• Additional contact points — extra buyer/tenderer contact fields.
• Framework agreements — extra fields for framework structure.

Limitations

• Publication quality varies. Even adopters have data completeness issues — missing dates, non-standard codelists, sparse award info.
• Not universal. Major publishers (US SAM.gov, most Middle East governments) don't yet publish OCDS.
• Language. OCDS is a schema, not a translator — narrative fields are in the publisher's language.
• Attachments still PDF. Bid documents, specifications, and contract text are typically referenced as PDF URLs, not structured within OCDS.

Where TenderYeti fits in

TenderYeti's scraping stack reads OCDS wherever it's published (Ukraine ProZorro, Slovakia, Moldova, UK Contracts Finder, etc.) and normalizes non-OCDS sources into a common internal schema so all 490+ portals become queryable through the same interface. See portal coverage.

Frequently asked questions