Data sources
Every fact in the reviews is based on an official page from the service provider. Below are the specific sources for each product and the date we last went through them. If you find something that doesn’t match, write to us: we fix errors and add a new check date.
What we count as a source
- The service provider’s official pricing and help pages.
- The provider’s news page — only for the status of new features and markets.
- Competitors’ official pages — only where their facts are used in a comparison table.
We don’t use forums, reviews written for search engines or unofficial prices as sources of facts. The prices you see in the price blocks are approved manually by the administrator — together with the source, check date and method.
Sources by product
Products: 57. Click a name to see that product’s sources.
Amazon Prime Video — 1 source
Checked . Amazon Prime Video review
Bitdefender — 1 source
Checked . Bitdefender review
ChatGPT — 4 sources
Checked . ChatGPT review
Coursera — 1 source
Checked . Coursera review
CyberGhost VPN — 2 sources
Checked . CyberGhost VPN review
ExpressVPN — 3 sources
Checked . ExpressVPN review
Google One — 1 source
Checked . Google One review
HBO Max — 1 source
Checked . HBO Max review
Microsoft OneDrive — 1 source
Checked . Microsoft OneDrive review
MyFitnessPal — 1 source
Checked . MyFitnessPal review
Nintendo Switch Online — 1 source
Checked . Nintendo Switch Online review
NordVPN — 3 sources
Checked . NordVPN review
Perplexity — 4 sources
Checked . Perplexity review
PlayStation Plus — 1 source
Checked . PlayStation Plus review
Private Internet Access — 1 source
Checked . Private Internet Access review
Proton Drive — 1 source
Checked . Proton Drive review
Proton VPN — 3 sources
Checked . Proton VPN review
Surfshark — 1 source
Checked . Surfshark review
Xbox Game Pass — 1 source
Checked . Xbox Game Pass review
Zwift — 1 source
Checked . Zwift review
Duolingo — 6 sources
Checked . Duolingo review
Babbel — 4 sources
Checked . Babbel review
TIDAL — 4 sources
Checked . TIDAL review
Udemy — 3 sources
Checked . Udemy review
WHOOP — 2 sources
Checked . WHOOP review
Garmin Connect+ — 2 sources
Checked . Garmin Connect+ review
McAfee — 2 sources
Checked . McAfee review
Lifesum — 3 sources
Checked . Lifesum review
Why the dates matter
Some information goes out of date quickly: sports rights, regional availability of features, catalog size and promotions. That’s why the reviews show the check date next to such claims: we don’t treat them as permanent properties of the product. You’ll find the methodology on the methodology page.