M-Lab NDT
M-Lab NDT measures a network connection’s capacity for bulk data transfer and reports upload speed, download speed, and latency.
What M-Lab NDT is
M-Lab NDT measures a network connection’s capacity for bulk data transfer and reports upload speed, download speed, and latency. Each test begins when a person runs it and measures how the network responds to a synthetic data stream. The free service is available through web, Android, iOS, Linux, and API clients. NDT supports ndt7, which uses TCP BBR where available and HTTP(S) ports 80 and 443, as well as ndt5 for legacy-client compatibility. M-Lab encourages integrations to use ndt7; support for ndt5+raw ended in January 2024. Test results are published for Internet research, and NDT data can be queried in BigQuery at no charge through Google Group subscription. Results include the connecting IP address and are retained publicly without a per-test deletion option. M-Lab says tests do not collect information about other Internet traffic or personally identifiable information. Organizations meeting its registration and technical requirements can host servers using Docker Compose.
Good
- Reports upload, download, and latency metrics
- Free access across web, mobile, Linux, and API
- Supports ndt7 and legacy ndt5 clients
- NDT data is available through BigQuery
Watch out
- Published test results include the connecting IP address
- Individual test data cannot be deleted
- ndt5+raw support ended in January 2024
Who it suits
NDT suits people who want to measure connection speed, and researchers, operators, regulators, or public-interest groups examining Internet performance. Its public results also make the connecting IP address visible indefinitely.
Verdict
NDT provides connection measurements and research data without a fee. Consider its indefinite public retention of results, including IP addresses, before running a test.
The facts
Each one read from M-Lab NDT's own pages, with the date it was checked.
What it does
- Audience
- M-Lab says its free, open Internet measurement data is intended to help researchers, regulators, advocacy groups, and the public understand Internet performance.checked 7 Oct 2026
- Client integrations
- M-Lab lists reference clients for Go and JavaScript and community-supported clients for iOS, Android, and C++.checked 7 Oct 2026
- Collected information
- NDT collects the user’s IP address along with measurement results; M-Lab says NDT does not collect information about the user as an Internet user.checked 7 Oct 2026
- Data collection
- NDT collects the user’s ISP-provided IP address with measurement results and publishes test results to support Internet research.checked 7 Oct 2026
- Data retention
- M-Lab says test data is published publicly and retained indefinitely, and it cannot delete data associated with an individual test once collected.checked 7 Oct 2026
- Diagnosis
- M-Lab describes NDT as testing connection speed and providing a sophisticated diagnosis of problems limiting speed.checked 7 Oct 2026
- Host eligibility
- Host-managed contributions are accepted from organizations such as ISPs, hosting providers, network operators, universities, research institutions, public-sector bodies, and qualifying nonprofits.checked 7 Oct 2026
- Hosting limits
- Host-managed nodes require Linux with Docker and tcp_bbr support, at least four 2 GHz CPUs, 4 GB RAM, 50 GB disk, and specified network connectivity and ports.checked 7 Oct 2026
- Host-managed data
- M-Lab says it does not manage host-managed servers or their software services, and keeps their data separate from data produced by M-Lab-managed servers.checked 7 Oct 2026
- Integrations
- M-Lab publishes NDT data through BigQuery and archives raw measurement data in Google Cloud Storage.checked 7 Oct 2026
- Intended users
- M-Lab describes its platform as supporting researchers and says its open performance data can be used by consumers, operators, regulators, researchers, and civil society.checked 7 Oct 2026
- Open source
- M-Lab states that all hosted tests are open source and created and maintained by researchers.checked 7 Oct 2026
- Privacy
- M-Lab says its tests do not collect information about other Internet traffic or personally identifiable information, while collected test data, including connecting IP addresses, is made public indefinitely and cannot be deleted per individual test.checked 7 Oct 2026
- Protocols
- NDT supports ndt5 for compatibility with legacy clients and ndt7, which uses TCP BBR where available and operates on HTTP(S) ports 80 and 443.checked 7 Oct 2026
- Protocol status
- M-Lab says support for ndt5+raw ended in January 2024 and encourages client integrations to use ndt7.checked 7 Oct 2026
- Purpose
- NDT measures a connection’s capacity for bulk transport and reports upload speed, download speed, and latency metrics.checked 7 Oct 2026
- Raw data
- Raw data and log files from the measurement fleet are archived in Google Cloud Storage, including packet captures for most NDT tests.checked 7 Oct 2026
- Research data
- NDT results are published for Internet research, and M-Lab offers query access to NDT data in BigQuery for free by Google Group subscription.checked 7 Oct 2026
- Self hosting
- Organizations can host M-Lab servers using Docker Compose, subject to M-Lab registration and technical requirements.checked 7 Oct 2026
- Support
- M-Lab directs NDT users to contact [email protected] for support.checked 7 Oct 2026
- Test method
- M-Lab tests run only when a person starts them and measure the network’s response to a synthetic data stream.checked 7 Oct 2026
- Transfer limit
- The ndt7 client supports an opt-in data transfer limit.checked 7 Oct 2026
Where it runs
- Client platforms
- The NDT page links to community-supported iOS and Android clients and reference Go and JavaScript clients.checked 7 Oct 2026
The company
- Founded
- 2009checked 28 Sep 2026
Alternatives to M-Lab NDT
- 1
PingPlotter
Free planiOSWebAPILinux8.2From $6.99 a month - 2
iPerf2
Free planOpen sourceAndroidiOSLinuxmacOS7.8Free plan - 3
GitHub CodeQL
Free planWebExtensionLinuxmacOS7.5From $30 a month - 4
Avidemux
Free planOpen sourceWebLinuxmacOSWindows7.3Free plan - 5
EVE-NG
Free planWebLinuxmacOSSelf-hosted7.0Free plan - 6
Netpicker
Free planWebAPILinuxSelf-hosted6.8From $7,500 a year