What Data Does the Tor Metrics Portal Provide?

The Tor Metrics portal serves as the primary public analytics archive for the Tor anonymity network, aggregating and visualizing historical and real-time data regarding the network’s ecosystem. This article outlines the specific categories of data available on the portal, including user adoption estimates, relay and bridge infrastructure metrics, network performance measurements, onion service activity, and censorship tracking indicators.

User Estimates and Demographics

Tor Metrics does not track individual IP addresses or personal identities, but it provides statistical estimates of the total daily active user base. Key user-related datasets include:

• Users by Country: Estimated number of daily connecting clients grouped by geographic origin.
• Direct vs. Bridge Connections: Counts distinguishing between users who connect directly to public relays and those using unlisted bridges.
• Transport Protocol Usage: The adoption rate of pluggable transports (such as obfs4, Snowflake, and meek) utilized to bypass local network censorship.

Relay and Bridge Infrastructure

The portal tracks the servers that form the backbone of the Tor network, offering comprehensive infrastructure analytics:

• Node Counts: The total number of running relays, exit nodes, and bridges over time.
• Network Bandwidth: Total advertised bandwidth, bandwidth capacity, and actual consumed bandwidth across the entire network.
• Geographic and Autonomous System (AS) Distribution: Relay locations by country and hosting provider/AS number.
• Platform Diversity: Operating system versions and Tor software release versions running on active relays.
• Relay Flags: The distribution of operational roles assigned to nodes, including Guard, Exit, Fast, Stable, and HSDir flags.

Network Performance

To monitor network quality and speed, Tor Metrics uses automated testing systems like OnionPerf to collect data on:

• Download Times: The time required to fetch files of various sizes (e.g., 50 KiB, 1 MiB, 5 MiB) over Tor circuits.
• Circuit Latency: Time to first byte (TTFB) and circuit construction latencies.
• Failure Rates: The percentage of circuit build attempts and data transfer requests that fail or time out.

Onion Services

Tor Metrics provides aggregate statistics regarding hidden services without revealing the identity or location of specific service operators:

• Hidden Service Count: An estimate of the total number of active .onion domains present in the network.
• Onion Traffic: The total volume of traffic routed to and from onion services, measured in gigabits per second (Gbit/s).

Applications and Censorship Tracking

The portal acts as a resource for researchers and advocates monitoring digital rights and internet freedom:

• Application Downloads: Download and update counts for the Tor Browser, segmented by operating system and language.
• Anomaly Detection: Sudden spikes or drops in user numbers that correlate with state-sponsored censorship events, network blocks, or civil unrest.