Privacy policy

Last updated 2 February 2018.

What is Blockmetry?

Blockmetry is a web analytics tool that measures website traffic in a privacy-conscious way. Blockmetry’s product goal is to measure website traffic while removing the possibility to identify or profile the website visitor. To rephrase, visitor privacy is at the heart of the Blockmetry product, and it’s balanced with the legitimate interest of our customers to get high-quality data to understand traffic to their websites. The full technical details about how Blockmetry works are beyond the scope of this document, although some specific points are described here as they are particularly relevant to privacy.

Who runs Blockmetry?

The Blockmetry service is owned and operated by Deliberate Digital Ltd, a company registered in England and Wales with company number 09866199. Our mailing address is:

Deliberate Digital
35 Wimbledon Hill Road, Wimbletech
SW19 7NB
United Kingdom
Our ICO registration is ZA313402.

Data processed to measure website traffic

Blockmetry processes website traffic data to produce reports that cannot identify or profile the website visitors on its own.

Sources of web analytics data

The data comes only from the standard HTTP request headers and what is available through JavaScript in browsers. This includes the user-agent string header (that identifies the browser), the header that communicates the browser’s language preference. We do not merge the web analytics data we produce with data from other sources.

No user identifiers or cookies

Blockmetry does not use unique identifiers for browsers/users. Blockmetry does not use cookies, and does not generate or use a browser or device fingerprint. Instead of tracking individuals through a unique identifier, Blockmetry assigns each measurement to a group of browsers sharing technical specs called anonymity sets or cohorts, identified by a Cohort ID.


Because Blockmetry does not track individuals, it cannot identify them nor profile them.

IP addresses and honoring the Do Not Track header

Blockmetry does not store Internet Protocol (IP) addresses, but the IP address is used as follows:

  1. The IP address is one of many signals used to identify bots (also called spiders or crawlers) that would pollute the analytics data Blockmetry produces.
  2. If the Do Not Track header is not set by the browser, the IP address is used to identify the perceived country and city the request is coming from, a step call geolocation.
  3. If the Do Not Track header is set by the browser, the IP address is ignored and the request is marked as coming from an unknown geolocation. Wikipedia has more information about the Do Not Track header.

Anonymization process

Blockmetry only processes the minimum data necessary to produce the final data for reporting. In addition to honoring the Do Not Track header, Blockmetry minimizes, normalizes, and anonymizes each measurement. This process discards a very large portion of the data Blockmetry receives with each request.

No cross-customer tracking

The process that generates the Cohort ID that identifies the anonymity set guarantees that the same browser visiting multiple Blockmetry customers will be assigned different Cohort IDs. This means it is impossible for Blockmetry or any of its customers to track visitors across websites from different customers.

EU-based data processing, export

Blockmetry supports several ways to make measurements. Regardless of how the measurements are made, the data is processed using EU-based datacenters. Blockmetry customers may instruct us to export the data outside the EU or EEA, and that’s a decision outside our service.

Why we process web analytics data

For Blockmetry customers

Blockmetry is a data processor that processes web data under the instruction of our customers. They sign up after agreeing a contract that includes:

  1. Provisions required by data protection laws such the UK’s Data Protection Act (1998) and the EU General Data Protection Regulation (GDPR);
  2. Instructions about how to customize Blockmetry’s processing about how their website (e.g. the URLs of the site) may inadvertently identify users, and how to mask these user identifiers.

For Blockmetry itself

When visiting the Blockmetry website itself, we process web analytics data because we have a legitimate interest in understanding how our visitors came to the website, what content they interacted with, and how they interacted with it.

Data processed when contacting Blockmetry

You may contact Blockmetry, for example by filling out the contact form or to sign up to use the service. If you do, we may collect your name and contact information. This data will only be used for the purpose of following up with you, and will be retained for up to a year before being deleted.

Data processed for the mailing list

You may subscribe to our mailing list. We use a third-party provider to manage our mailing list and send out the emails. You can unsubscribe any time you wish. While subscribed, our provider will store your name and email address, and we will use your details only for sending you emails via the mailing list.

Privacy policy changes

We may need to update the this privacy policy, for example, if the product changes. We will do so at our discretion, and will:

  1. Announce the change on the website;
  2. Update this page with the changes;
  3. Update the date at the top of this policy.

Questions, comments, feedback

We would love to hear any questions, comments, or feedback about this privacy policy or anything related to Blockmetry. Please fill out the form on the contact page.