Between Lexical Computing CZ s.r.o. and you, the customer

The Sketch Engine, as installed at is a web service belonging to Lexical Computing CZ s.r.o. (LCC) and used under permission by the customer. The Sketch Engine will normally be available continuously. It is hosted on a cluster of dedicated servers owned and operated by LCC in datacenters.

Electronic access to the Sketch Engine servers is by username and password using standard security protocols. The integrity of the servers in relation to hacker attacks and similar is closely monitored. Access protocols involve two-factor security mechanisms and are regularly updated.

New versions of the software are tested extensively before they are brought into service. We try hard to make Sketch Engine working with majority of web browsers (mainly focusing on Google Chrome and Mozilla Firefox) but generally require users to use the most recent versions of these browsers and may require to use a particular browser type and version in case of difficulties.

LCC stipulates that all incidents are to be reported using e-mail to and not any other address (in particular not e-mail addresses of individual Sketch Engine team members) or using the online feedback form in Sketch Engine. All bug reports and incidents are counted as such from the time they are first reported by the customer.

LCC operates backup servers in addition to its main servers. Backups are conducted twice a week. In the event of a major failure, main servers are rebuilt from the backup server.

LCC guarantees that:

  1. Any individual outage in excess of twelve hours outside the working week will constitute a violation.
  2. Any sum of outages exceeding twelve hours in any period of consecutive 30 days will constitute a violation.
  3. The Sketch Engine team will respond to incidents that prevent or severely limit more than 10 users from using the service within 24 hours and resolve the problem within further 24 hours. Missing any of these metrics on an incident will constitute a violation.
  4. The Sketch Engine team will respond to service incidents that prevent or severely limit an individual user from using the service within 48 hours and resolve the problem within further 48 hours. Missing any of these metrics on an incident will constitute a violation.
  5. The Sketch Engine team will respond to non-critical inquiries within 72 hours. Missing this metric will not constitute a violation. A non-critical inquiry is defined as a request for information that has no impact on the service quality if not answered or acted upon promptly.
  6. Incidents will not be classified as violations if they are caused by:
    • force majeure
    • the customer, customer’s employees or customer’s auxiliary persons
    • unavoidable service impairments due to changes in the service which have been ordered by the customer, or have become mandatory because of legal or regulatory demands
    • scheduled maintenance, as long as it does not exceed 96 hours in total in any period of consecutive 30 days.
  7. In addition to the main service, LCC will usually operate a beta (i.e. testing) service at The beta service is not covered by this agreement.
  8. The Sketch Engine team will announce scheduled maintenance which may have an effect on the customer’s services at least three working days in advance. This announcement will be made on the login screen.
  9. LCC is only liable for non-compliance with the service level specified if it is solely responsible for the non-compliance. In particular incidents will not count as violations if the incident results from:
    • external DNS server problems, electronic attacks on LCC’s servers, network or e-mail infrastructure, and failures of parts of the internet not under the control of LCC
    • customers, especially breakdowns due to incoming or outgoing hacker attacks (DoS) resulting from faulty or insufficient maintenance of the customer’s network.
      If LCC can prove for any asserted claim by a customer that it is not a valid warranty claim, the error diagnostics and troubleshooting will be at the expense of the customer.
  10. Number of violations per year and associated penalties
    • 1–3 violations: no penalty
    • 4–8 violations: 10% reduction in licence fee for the year
    • >8: 20% reduction in fees plus LCC to provide customer with a plan to improve the service, to be ratified by the customer.
  11. The service is subject to a fair use policy (FUP) in order to prevent massive overloading by individual users at the cost of others. The FUP limit applies to the number of requests (not to the volume of data transferred) per one minute, one hour and one day and defaulting to 100, 900 and 2,000 requests, respectively. Further requests will be denied automatically upon exceeding any of these limits. Applying FUP does not constitute a violation and LCC reserves the right to take measures to prevent customers violating the FUP from using the service.

Last modified 25th April 2018.