Filter syntax
The filter parameter uses a compact field:value grammar that replaces the individual query parameters of previous API versions.
Operators
| Operator | Meaning | Example |
|---|---|---|
, | AND across fields | funder_short_name:EC,country:GR |
| | OR within a field | funder_short_name:EC|NIH |
! | Negation | country:!DE |
> | Greater than (years) | start_year:>2022 |
< | Less than (years) | end_year:<2026 |
Filters are combined with AND (comma). Within a single field, use pipe (|) for OR. These cannot be mixed — each field entry is either a single value, a negation, a range, or an OR-list.
Filter fields
Identity
| Field | Type | OR | NOT | Facetable | Example |
|---|---|---|---|---|---|
id | string | ✓ | ✓ | — | id:100007490___::1e5e62235d094afd01cd56e65112fc63 |
code | string | ✓ | ✓ | — | code:101017452 |
acronym | string | ✓ | ✓ | — | acronym:OpenAIRE |
pid | string | ✓ | ✓ | — | pid:10.3030/101017452 |
call_identifier | string | ✓ | ✓ | ✓ | call_identifier:H2020-INFRAEOSC-2018-2 |
project_status | enum | ✓ | ✓ | ✓ | project_status:ongoing — one of completed, ongoing, planned |
Text search sub-filters
These fields allow targeted text searches within specific parts of the project. They are used inside the filter parameter, unlike the top-level search parameter which searches across all default fields.
| Field | Description | Example |
|---|---|---|
title.search | Search within the project title | title.search:open science |
keywords.search | Search within the project keywords | keywords.search:infrastructure |
default.search | Search all default fields (same as top-level search) | default.search:climate |
Funding
| Field | Type | OR | NOT | Facetable | Example |
|---|---|---|---|---|---|
funder | string | ✓ | ✓ | ✓ | funder:European Commission |
funder_short_name | string | ✓ | ✓ | ✓ | funder_short_name:EC|NIH |
funding_stream_id | string | ✓ | ✓ | — | funding_stream_id:H2020 |
funding_level_0_id | string | ✓ | ✓ | — | funding_level_0_id:ec__________::EC::FP7 |
funding_level_1_id | string | ✓ | ✓ | — | funding_level_1_id:ec__________::EC::FP7::SP1 |
funding_level_2_id | string | ✓ | ✓ | — | funding_level_2_id:ec__________::EC::FP7::SP1::HEALTH |
Country
| Field | Type | OR | NOT | Facetable | Example |
|---|---|---|---|---|---|
country | string | ✓ | ✓ | ✓ | country:GR|IT |
continent | enum | ✓ | ✓ | — | continent:europe |
is_global_south | boolean | — | ✓ | — | is_global_south:true |
continent accepts africa, antarctica, asia, europe, north_america, oceania or south_america; an unknown name is rejected with a 400 listing the valid ones. Both fields expand server-side into the matching ISO country codes — drawn from the UN Statistics Division M49 classification and the UN Finance Center for South-South Cooperation respectively — so they are not facetable.
A single field accepts at most 50 pipe-separated values; beyond that the request is rejected with a 400 naming the field. Server-side expansion such as continent:europe does not count toward that limit.
Open Access mandate
| Field | Type | OR | NOT | Facetable | Example |
|---|---|---|---|---|---|
oa_mandate_publications | boolean | — | ✓ | ✓ | oa_mandate_publications:true |
Dates and years
Date ranges use from_/to_ prefix pairs; year fields accept an exact value or an open-ended range with > / <.
| Field | Type | Format | Description |
|---|---|---|---|
from_start_date | date | YYYY or YYYY-MM-DD | Start date >= value |
to_start_date | date | YYYY or YYYY-MM-DD | Start date <= value |
from_end_date | date | YYYY or YYYY-MM-DD | End date >= value |
to_end_date | date | YYYY or YYYY-MM-DD | End date <= value |
start_year | int | YYYY | Exact start year; supports > / < (facetable) |
end_year | int | YYYY | Exact end year; supports > / < (facetable) |
active_year | int | YYYY | Projects active in the given year (started on/before and ending on/after) |
Relations
| Field | Type | OR | NOT | Facetable | Example |
|---|---|---|---|---|---|
organizations.id | string | ✓ | ✓ | ✓ | OpenAIRE organization id |
organizations.name | string | ✓ | ✓ | — | organizations.name:University of Athens |
organizations.country | string | ✓ | ✓ | ✓ | organizations.country:GR |
communities.id | string | ✓ | ✓ | ✓ | communities.id:neuroscience |
collected_from.id | string | ✓ | ✓ | ✓ | collected_from.id:openaire____::9e9e8c76d739212c63eff362e321ba33 |
Combined examples
EC H2020 projects active in 2022:
/v4/projects?filter=funder_short_name:EC,funding_stream_id:H2020,active_year:2022Greek projects starting from 2020 with an OA mandate:
/v4/projects?filter=country:DE,start_year:>2019Multi-funder, sorted by start date:
/v4/projects?filter=funder_short_name:EC|NIH&sort=start_date:desc&page_size=20