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M-Lab NDT
What it is
M-Lab NDT measures a connection’s capacity for bulk data transfer and reports upload speed, download speed, and latency. A test runs when a person starts it and measures the network’s response to a synthetic data stream. NDT supports ndt7, which uses TCP BBR where available and HTTP(S) ports 80 and 443, and ndt5 for compatibility with legacy clients. M-Lab encourages integrations to use ndt7; support for ndt5+raw ended in January 2024. The service is free, with web, Android, iOS, Linux, and API access. Results are published for Internet research, and NDT data can be queried in BigQuery for free through Google Group subscription. Published test results include the connecting IP address and are retained indefinitely; M-Lab says it cannot delete data from an individual test after collection. It also says tests do not collect information about other Internet traffic or personally identifiable information. Organizations that meet registration and technical requirements can host M-Lab servers using Docker Compose.
For and against
For
- Reports upload, download, and latency metrics
- Tests start only when a person runs them
- Free access through web, mobile, Linux, and API
- NDT data is available through BigQuery
- Organizations can host servers with Docker Compose
Against
- Published test results include the connecting IP address
- Test data is retained indefinitely
- Individual test data cannot be deleted after collection
- Support for ndt5+raw ended in January 2024
The verdict
NDT provides on-demand connection measurements and makes results available for Internet research. Before running a test, consider that its results include the connecting IP address and remain public indefinitely.
Who it suits
NDT suits people who want to measure connection speed and organizations or researchers who use Internet performance data. Its published results may also serve consumers, operators, regulators, and civil society.
On the record
- Audience
- M-Lab says its free, open Internet measurement data is intended to help researchers, regulators, advocacy groups, and the public understand Internet performance.measurementlab.net · read 7 Oct 2026
- Client integrations
- M-Lab lists reference clients for Go and JavaScript and community-supported clients for iOS, Android, and C++.measurementlab.net · read 7 Oct 2026
- Client platforms
- The NDT page links to community-supported iOS and Android clients and reference Go and JavaScript clients.measurementlab.net · read 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.measurementlab.net · read 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.measurementlab.net · read 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.measurementlab.net · read 7 Oct 2026
- Diagnosis
- M-Lab describes NDT as testing connection speed and providing a sophisticated diagnosis of problems limiting speed.measurementlab.net · read 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.measurementlab.net · read 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.measurementlab.net · read 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.measurementlab.net · read 7 Oct 2026
- Integrations
- M-Lab publishes NDT data through BigQuery and archives raw measurement data in Google Cloud Storage.measurementlab.net · read 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.measurementlab.net · read 7 Oct 2026
- Open source
- M-Lab states that all hosted tests are open source and created and maintained by researchers.measurementlab.net · read 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.measurementlab.net · read 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.measurementlab.net · read 7 Oct 2026
- Protocol status
- M-Lab says support for ndt5+raw ended in January 2024 and encourages client integrations to use ndt7.measurementlab.net · read 7 Oct 2026
- Purpose
- NDT measures a connection’s capacity for bulk transport and reports upload speed, download speed, and latency metrics.measurementlab.net · read 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.measurementlab.net · read 7 Oct 2026
