ooni.org

One-line introduction

ooni.org is an open-source project launched by OONI (Open Observatory of Network Interference), a global internet freedom initiative. It aims to detect network blocking, traffic manipulation, and censorship worldwide through distributed measurement points. By running OONI Probe—available for desktop, mobile, and command line—users can collect data on traffic filtering in their local network environment and upload the results to a public dataset, helping researchers and the public understand the current state of internet control. The project is nonprofit, transparent, and community-driven, making it suitable for technical users interested in censorship research, data sovereignty, or internet transparency.

Business overview

OONI is operated by a nonprofit under the Tor Project and has been measuring global network interference since 2012. Its core offering is a suite of open-source network measurement tools, including OONI Probe for desktop (Windows/macOS/Linux), mobile (Android/iOS), and command line. Once installed, the tool automatically runs a range of tests, such as HTTP request blocking detection, DNS tampering identification, HTTPS interference checks, and connectivity tests for popular apps such as Telegram and WhatsApp. After anonymization, all test results are synced to OONI’s public database, OONI Explorer, where researchers, journalists, and civil society organizations around the world can analyze them. OONI is not a commercial service but a research project, so it does not offer paid plans or SLA guarantees. In its field, it is a benchmark project for measuring internet censorship, alongside organizations such as GreatFire and Citizen Lab, with a stronger emphasis on community participation and open-source collaboration.

Who it is for

OONI is aimed at individuals or organizations with some technical background, especially internet freedom activists, academic researchers, journalists, VPN provider QA teams, and ordinary users concerned about network sovereignty. For individual users who want to know whether their home broadband or mobile network is subject to specific blocking—for example, whether certain websites are inaccessible or throttled—OONI Probe provides easy-to-understand local test reports. For research institutions, the large datasets in OONI Explorer can be used for long-term trend analysis, such as comparing changes in internet controls across countries during major events. However, it is not suitable for businesses that need real-time network monitoring or commercial-grade anti-censorship solutions, because the tool itself does not bypass blocking; it only performs passive measurement.

Key features and highlights

• Open source and transparent: All code is hosted on GitHub, and the testing methods, algorithms, and result data are fully public and auditable, with no hidden backdoors.
• Multi-protocol measurement: Supports interference testing for common protocols and services including HTTP, HTTPS, DNS, TLS handshakes, and Tor connectivity, offering broad coverage.
• Global data aggregation: OONI Explorer provides interactive maps and timelines for viewing blocking trends in specific countries or regions, with real-time data updates.
• Lightweight deployment: The mobile app only requires a few dozen MB of storage and can run in the background without affecting daily use; the command-line version is suitable for long-term operation on servers or Raspberry Pi devices.
• Automation and scheduled testing: Users can configure automated testing schedules, such as once per hour, to continuously collect data on network changes without manual intervention.
• Privacy-first design: Apart from the IPs and domains being tested, it does not collect user location, device information, or real IP addresses, and test results are anonymized by default before upload.

Pricing analysis

OONI is a completely free open-source project with no plans or subscription fees. Users can download the tools, run tests, and access public data without paying monthly or annual fees. That said, running a measurement point consumes network traffic depending on the frequency and type of tests, though the usage is usually very small—typically within a few dozen MB per month. If users want to deploy a large-scale measurement network, such as running OONI on multiple cloud servers, they must cover the server or VPS costs themselves. The project accepts donations, but they are not mandatory. Overall, OONI is a zero-cost option among similar tools and offers excellent value, provided users can handle technical deployment and result interpretation on their own.

How Chinese users can use it

Network accessibility: OONI Probe’s official website, ooni.org, and OONI Explorer are directly accessible from mainland China, but downloading the tools—especially from the GitHub Release page—may require a proxy. When running tests, some items such as Tor connectivity tests may be interfered with by the firewall, leading to incomplete results; basic HTTP/DNS tests usually work normally.
Payment methods: There is no paid process, so payment methods are not a concern.
Is circumvention required: It is recommended to enable a stable proxy before running tests to ensure that all test items, especially HTTPS- and Tor-related ones, can be triggered properly. However, note that the results will reflect the network conditions under the proxy environment and may not accurately represent the native network.
Domestic alternatives: There are currently no directly comparable, publicly available open-source tools in China. Some domestic security teams use in-house scripts or commercial platforms such as Alibaba Cloud CloudMonitor to check CDN node availability, but these lack OONI’s global collaboration and censorship-measurement dimensions. For ordinary users, GreatFire’s test results are a useful supplementary reference.

Pros and cons

Pros

• ✅ Completely free and open source, with no commercial lock-in risk.
• ✅ Public and transparent data, suitable for academic research and fact-checking.
• ✅ Multi-platform support and flexible deployment.
• ✅ Strong privacy protections and a high degree of user anonymity.
• ✅ Active community, with developers continuously updating the test library.

Cons

• ❌ Requires some technical knowledge, such as installing command-line tools and interpreting JSON reports.
• ❌ Does not provide censorship circumvention; it only performs passive detection.
• ❌ No Chinese interface or documentation, making it less friendly for non-English users.
• ❌ Some tests in China require a proxy, and results may be affected by the proxy environment.
• ❌ No after-sales support; users need to rely on the community or GitHub Issues for troubleshooting.

Comparison with similar products

• GreatFire（GFW Test）: Focuses on detecting the Chinese firewall and offers simpler web-based tests, such as checking whether a website is accessible, but it is not open source and its data is not public. OONI is better suited to a global perspective and long-term data collection.
• Citizen Lab（NetAlert）: Also a nonprofit research project, but it focuses more on application-layer blocking, such as WeChat and WhatsApp, and its testing tools are relatively limited. OONI offers broader protocol coverage.
• Commercial monitoring platforms（such as ThousandEyes）: Provide enterprise-grade network performance monitoring and support blocking detection, but are expensive, often costing thousands of dollars per month. OONI is a zero-cost alternative, but lacks an SLA and a visual management console.

Final recommendation

OONI is best suited for technical users who want a low-cost, open-source way to understand local network blocking, especially researchers or journalists who need to track changes in internet controls over time. For ordinary Chinese users, if the goal is simply to confirm whether a certain website is blocked, it is better to start with GreatFire or manual testing. If you need to systematically record the filtering rules of a home broadband or mobile network and are willing to spend time configuring the tool and interpreting the data, OONI is an excellent choice. It is not suitable for scenarios that require immediate censorship circumvention, where a VPN or Tor would be more appropriate; commercial-grade reporting, where a paid service is better; or complete beginners, who should start with the automatic mode in the OONI Probe desktop version or mobile app. Since the project is completely free, it is worth downloading and trying directly without worrying about payment risk.