Open Science Framework API

Free Open Science Framework API with no key for public data: projects, registrations, preprints, files and contributors in JSON:API format. Tested example and live response.

No API key requiredHTTPSFree tier

Endpoint tested and returned HTTP 200 on 2026-08-21

What is the Open Science Framework API?

The Open Science Framework API is a free REST interface to OSF's public research projects, preregistrations, preprints and files. Public data is readable without authentication; a personal access token is only needed for private content or to write.

OSF is where a large slice of psychology, education and social science now keeps its preregistrations, materials and data. The API exposes all of the public side: projects (called nodes), their contributors, their file trees, registrations and the preprint servers OSF hosts. For meta-research and reproducibility tooling it is the primary source, because preregistrations carry timestamps that cannot be edited after the fact.

The API follows JSON:API strictly, which is a mixed blessing. Every object separates `attributes` from `relationships`, and relationships are returned as links rather than embedded data — so getting a project's contributors means following `relationships.contributors.links.related.href` rather than reading an array. Bracketed query parameters (`page[size]`, `filter[title]`) need URL-encoding in most HTTP clients. Anonymous access is throttled fairly aggressively, so anything beyond casual polling wants a token even though the data itself is public.

Quick facts

Base URL: https://api.osf.io/v2
Authentication: No key needed to read public nodes, registrations and preprints. A free personal access token raises the rate limit and is required for private projects or any write operation.
Rate limit: Anonymous requests are throttled per IP and will return HTTP 429 under sustained use. Authenticated requests with a personal access token get a substantially higher allowance.
Pricing: Free. OSF is run by the non-profit Center for Open Science; individual projects set their own licence, exposed as `node_license`.
CORS: Not enabled — call it from your server
Official docs: Read the docs

How to use the Open Science Framework API

Every request below was executed against the live API on 2026-08-21, and the response shown is the real body it returned — not an illustration.

1. List public OSF projects, one per page

GET https://api.osf.io/v2/nodes/?page%5Bsize%5D=1

curl

curl 'https://api.osf.io/v2/nodes/?page%5Bsize%5D=1'

JavaScript (fetch)

const res = await fetch("https://api.osf.io/v2/nodes/?page%5Bsize%5D=1");
if (!res.ok) throw new Error(`Request failed: ${res.status}`);
const data = await res.json();
console.log(data);

Python (requests)

import requests

res = requests.get("https://api.osf.io/v2/nodes/?page%5Bsize%5D=1", timeout=20)
res.raise_for_status()
print(res.json())

Response — HTTP 200

{
  "data": [
    {
      "id": "wmx2h",
      "type": "nodes",
      "attributes": {
        "title": "The effect of anonymity on willingness to testify",
        "description": "",
        "category": "project",
        "custom_citation": null,
        "date_created": "2025-02-05T10:40:56.699961",
        "date_modified": "2026-08-21T07:38:31.695545",
        "registration": false,
        "preprint": false,
        "fork": false,
        "collection": false,
        "tags": [],
        "access_requests_enabled": true,
        "node_license": null,
        "analytics_key": "",
        "current_user_can_comment": false,
        "current_user_permissions": [
          "read"
        ],
        "current_user_is_contributor": false,
        "current_user_is_contributor_or_group_member": false,
        "wiki_enabled": true,
        "public": true,
        "subjects": []
      },
      "relationships": {
        "children": {
          "links": {
            "related": {
              "href": "https://api.osf.io/v2/nodes/wmx2h/children/",
              "meta": {}
            }
          }
        },
        "collected_in": {
          "links": {
            "related": {
              "href": "https://api.osf.io/v2/nodes/wmx2h/collections/",
              "meta": {}
            }
          }
        },
        "comments": {
          "links": {
            "related": {
              "href": "https://api.osf.io/v2/nodes/wmx2h/comments/?filter%5Btarget%5D=wmx2h",
              "meta": {}
            }
          }
        },
        "contributors": {
          "links": {

Parameters

Parameter	Type	Required	Description
`page[size]`	query	Optional	Results per page, up to 100. Bracket characters must be URL-encoded. `10`
`page`	query	Optional	One-based page number. `1`
`filter[title]`	query	Optional	Filter nodes by title substring. Most attributes support a `filter[...]` form. `replication`
`embed`	query	Optional	Embed a related resource inline instead of returning a link, saving a round trip. `contributors`
`sort`	query	Optional	Sort field; prefix with `-` for descending. `-date_modified`

Response fields

data[].idstring: The five-character OSF GUID, which is also the public URL path for the project.
data[].typestring: JSON:API resource type — `nodes`, `registrations`, `preprints`, `files` and so on.
attributes.title / descriptionstring: Project title and description as entered by the researchers.
attributes.categorystring: Self-declared project type such as `project`, `data`, `analysis` or `methods and measures`.
attributes.registrationboolean: True for frozen preregistrations, which cannot be edited after submission.
attributes.publicboolean: Whether the node is publicly visible. The anonymous API only ever returns true here.
relationshipsobject: Links to related resources. Follow the `related.href` values, or use `embed` to inline them.

What you can build with the Open Science Framework API

Harvest preregistrations for a meta-research study
Mirror a lab's public project list onto its own website
Monitor a project for new files or contributors
Cross-reference preprints to their underlying data and materials
Check whether an analysis plan was registered before data collection

Common errors and how to fix them

429

Anonymous throttle exceeded.

Fix: Slow down and cache. A free personal access token, sent as a bearer header, raises the ceiling considerably.

400 on filter or page parameters

Square brackets were sent unencoded.

Fix: Encode them as `%5B` and `%5D`. Several HTTP clients do this automatically and several do not.

Empty relationships

JSON:API returns links, not embedded objects.

Fix: Follow `relationships.<name>.links.related.href`, or add `embed=<name>` to inline the resource in the same response.

404 on a project you can see in a browser

The node is private or view-only.

Fix: Anonymous API access sees public nodes only. View-only links are a web-interface feature and do not extend to the API.

Open Science Framework API — frequently asked questions

Do I need an OSF account to use the API?

Not for reading public projects, registrations and preprints — those work anonymously. You need a free personal access token for private content, for writing, and in practice for any sustained read volume because of the anonymous rate limit.

What is the difference between a node and a registration on OSF?

A node is a live project that contributors can edit. A registration is a frozen, timestamped snapshot of a node, typically a preregistered analysis plan, which cannot be changed afterwards. That immutability is why registrations are the interesting object for meta-research.

Why are contributors not included in the project response?

OSF follows the JSON:API specification, which returns relationships as links rather than embedded data. Either follow the link in `relationships.contributors` or request `embed=contributors` to have it inlined.

Can I download files through the API?

Yes. File objects carry download links that resolve through OSF's storage service. The metadata API describes the file tree; the actual bytes come from those separate URLs.

Tools that pair with this API

JSON Formatter

Format, beautify and minify JSON online with 2-space, 4-space or tab indentation. Sort keys alphabetically and catch syntax errors instantly — free and private.

JSON Path Finder

Evaluate a dot/bracket path against your JSON and list every leaf path for discovery. Free online JSON path finder that runs 100% in your browser.

JSON to CSV Converter

Convert a JSON array of objects to CSV online. Automatic column headers from the union of all keys, delimiter choice and proper quoting — all in-browser.

Open Science Framework is an independent third-party service and is not affiliated with ByteTools or ByteVancer. Details on this page were verified on 2026-08-21; always check the official documentation before relying on this API in production, as terms and limits can change.