What is OONI (Open Observatory of Network Interference)?

OONI is a global community project that measures internet censorship around the world. It runs two main tools: OONI Probe, which you install to test whether websites and apps are blocked and to measure network speed and performance, and OONI Explorer, a public interface for tracking censorship worldwide in near real time. The project publishes its measurements as an open dataset — millions of measurements collected from more than 200 countries since 2012 — which makes it useful if you want to check whether a specific site or service is reachable from a given network, or if you need evidence for research, journalism, or advocacy.

What OONI actually does

OONI collects data by having volunteers run tests from their own networks. Each test produces a measurement: a record of what happened when a specific site, app, or service was accessed from a particular location at a particular time. Those measurements are then aggregated and published.

Two components do the work:

• OONI Probe — the client software you run to perform the tests. According to OONI's own description, it is used to "test the blocking of websites and apps" and to "measure the speed and performance of your network."
• OONI Explorer — the web interface for browsing the resulting data. OONI describes it as a way to "track internet censorship worldwide in near real-time," and it hosts what the project calls "the world's largest open dataset on internet censorship."

The data behind it

Because the dataset is open, you are not limited to reading OONI's own summaries — you can look at the underlying measurements for a country, a time window, or a specific service.

What the data is used for

OONI's published research shows the range of questions the measurements can answer. Recent examples listed on the site include:

• Italy blocks reproductive health websites — Women on Web (WoW) and Women Help Women (WHW)
• Collateral damage of IP-based blocking during LALIGA football streaming in Spain — evidence drawn from OONI measurements
• Abortion access denied — an investigation into global censorship of Women on Web
• How internet censorship impacts the women's rights movement in Iran — insights from OONI data and activist interviews
• Throttling of social media in Türkiye during protests — an analysis of OONI data

These illustrate the two common uses: documenting that a block or throttle is happening, and connecting that technical finding to its social or legal consequences.

When OONI is the right tool

OONI fits situations where you need network-level evidence of blocking or throttling from real vantage points, rather than a single test from one machine. It is a good match if you are:

• A researcher or journalist who needs citable, timestamped measurements
• An advocate documenting censorship of a specific site or category of sites
• Someone who wants to contribute measurements from your own network by running OONI Probe

It is less suited to questions OONI does not claim to answer — for example, why a block was imposed, or whether a service is down for reasons unrelated to censorship. OONI measures interference; interpreting cause and intent is a separate step, which is why its research posts pair measurements with context and interviews.

How to start

1. To contribute data: install OONI Probe and run the tests. The site's "Get Involved" section is the entry point.
2. To look at existing data: open OONI Explorer and browse by country or service.
3. To understand the methodology: OONI publishes its testing methodologies, plus a glossary and FAQ for terminology.

If you only need a quick answer to "is this site blocked where I am," running OONI Probe from that network and then checking the result in OONI Explorer covers both the test and the comparison against other measurements.