I've had to decline/accept cookies for a while now. But something I've noticed on a handful of websites are now suggesting that the cookies have 'legitimate interest'? I have a legitimate interest in IRL cookies I can eat, but I do not know what it means for a website to share that interest for internet cookies?

What's more interesting/puzzling whereas most websites have all cookies opted out (where possible), the ones that do suggest 'legitimate interest' are always switched on.

What do these settings mean for me? Can I allow them, or should I have them all switched off as I do with other non-essential cookies?

  • 14
    Might be better asked at law.stackexchange.com, which has a whole tag for GDPR-related questions.
    – user1686
    Feb 8, 2021 at 15:05
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    @user1686 I don't need a legally informed answer, but one for a layman website user. Otherwise that would be a good idea Feb 8, 2021 at 15:30
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    For a majority of websites, logins don't work without cookies. There are ways to design websites that don't depend on cookies for example using unique query parameters as pseudo cookies (an old hack before cookies were invented) and using localStorage instead of cookies (it's still basically cookies but not using the cookie mechanism - basically a DIY cookie) but most websites still use cookies to manage sessions
    – slebetman
    Feb 9, 2021 at 6:00
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    @slebetman Or you can use the good old HTTP Basic Auth mechanism to authenticate user on every page, thus you don't need cookies for login.
    – raj
    Feb 9, 2021 at 10:12
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    @Pureferret: But "Legitimate Interest" is a specific legal term from the GDPR with a precise definition in relation to the GDPR. These two words in this combination in this context have nothing to do with the English words "legitimate" and "interest". They mean precisely what the GDPR says they mean, nothing more, nothing less, in exactly the same way that the word "cookie" in this question has a precise technical meaning that has nothing to do with the normal English meaning. That is, unfortunately, how jargon works. Feb 9, 2021 at 20:24

3 Answers 3


Legitimate interest is a legal term from GDPR. You should read the GDPR to get a detailed explantion what it is :), but in short it's any legal reason that justifies the need to process your personal data by the site. For example, if you order something from an Internet shop, the shop's legitimate interest to process your data is the need to complete your order.

However, the legitimate interest concept is often abused by sites and they list for example tracking users in order to "protect from fraud" as legitimate interest. If there is an option to turn this off, turn off whatever possible. If there is something that is really needed for the site to function, you won't be able to turn that off :)

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    Good answer but possibly a bad example. Fraud prevention is explicitly defined in GDPR as a legitimate interest. Section 47 : “The processing of personal data strictly necessary for the purposes of preventing fraud also constitutes a legitimate interest of the data controller concerned.” Of course this may be abused...
    – lx07
    Feb 8, 2021 at 16:01
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    Yes, but I was thinking specifically about misusing this, ie. the site tells you that it is collecting data for the purpose of fraud prevention and lists this as a legitimate interest "just in case", regardless of whether it actually uses the data for that purpose or not. I have probably similar experience to OP: I have seen sites that list a dozen of different "legitimate interests", turned on by default, but you can turn them off. If you can turn them off, then they aren't probably actually so necessary to the site...
    – raj
    Feb 8, 2021 at 16:08
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    @BernhardDöbler sorry, but I don't remember all the sites where I had to turn off all the "legitimate interests" they displayed to me. It would be absurd to remember that. However, there was a significant number of them, it wasn't just one or two sites.
    – raj
    Feb 9, 2021 at 14:23
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    @BernhardDöbler Try sussexlive.co.uk and see if you can work out what "Legitimate Interest" is supposed to mean.
    – Simon B
    Feb 9, 2021 at 20:20
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    -1 This is incorrect, legitimate interests is a different ground for processing than 'to fulfill your contract' of which 'complete your order' is an example. Feb 9, 2021 at 21:35

Under GDPR there are 6 grounds based on which anybody can process personal data. Those are:

  • Consent

    You explicitly agreeing to it. This needs to be opt-in, informed, specific and freely given, but also gives the greatest freedom to a company.

  • Contract

    This is the basis which raj's answer confused with legitimate interests. This is the processing that is required to fulfil a contractual obligation (note that contracts do not always need to be signed, e.g. an order from an eshop).

    need to process someone’s personal data:

    • to deliver a contractual service to them; or
    • because they have asked you to do something before entering into a contract (eg provide a quote).

             Source: ico.org.uk

  • Legal obligation

  • Vital interests

  • Public task

  • Legitimate interests

    Legitimate interests are the most flexible lawful basis for processing personal data. In the words of the UK's ICO 1:

    It is likely to be most appropriate where you use people’s data in ways they would reasonably expect and which have a minimal privacy impact, or where there is a compelling justification for the processing.

             Source: ico.org.uk (worth reading!!!)

    The underlying text from the GDPR itself (definitions and links added are mine)

    processing is necessary for the purposes [=a specific minimal type of processing] of the legitimate interests pursued by the controller [=the company wanting to process your data] or by a third party except where such interests are overridden by the interests or fundamental rights and freedoms of the data subject [=you] which require protection of personal data, in particular where the data subject is a child.

             Source: GDPR Article 6(1f)

    So basically a legitimate interest claim by a company is them saying 'we are convinced that our interest outweigh the negligible impact on the privacy of the people whose data we process'. This doesn't give them a free pass though, as GDPR also gives the right to object

    The data subject shall have the right to object, on grounds relating to his or her particular situation, at any time to processing of personal data concerning him or her which is based on point [public interest] or [legitimate interest] of Article 6(1), including profiling based on those provisions.

             Source: GDPR Article 21(1)

    Which then require the company to either concede and stop the processing or justify their claim. Companies in practise have taken this to mean they can basically just do a bunch of processing and as long as they make the objection process (=opt-out) easy enough the theory is that they will get away with it.


1 The UK left the EU, but they still have by far the best English language resource explaining GDPR and for the time being "UK GDPR" matches "EU GDPR" one on one as far as I am aware.

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    I think it's worth pointing out here that all of these claims are limited in scope, so, consenting to your data being used to prevent fraud doesn't give rights for the company to add you to their mailing list. Similarly, processing data for the legitimate interest of fraud prevention doesn't give free rein for the company to use it in analytics -they're supposed to spell out exactly what they'll use your data for.
    – lupe
    Feb 10, 2021 at 15:13
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    Your summing up of what a legitimate interest is is a bit underspecified. For example, an ecommerce store would use legitimate interest to process a customer’s address; no customer would feel strange about that. On the other hand, the legitimate interests in the newer popups are, to be frank, an attempt to work around the rules. Feb 11, 2021 at 11:03
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    @RobinWhittleton To process an address to do what? Processing an address to send you their order would be processing based on a contract, not a legitimate interest. Processing an address to send you marketing materials would require consent. Processing past addresses by themselves (=pseudo anonymised) to evaluate which delivery company would be on average cheapest for your customers could be justified based on a legitimate interest. Feb 11, 2021 at 12:49
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    No, the site would have to store and potentially process the address before a contract is in place. For example, your system might use a postcode to find out whether it was possible to ship to an area. Feb 11, 2021 at 15:30
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    @RobinWhittleton A postcode by itself wouldn't be personal data (postcode + house number would sometimes be though). And even if you would use the full address for that, that's explicitly covered under the contract ground for processing (ico's summary: "because they have asked you to do something before entering into a contract (eg provide a quote).") Feb 11, 2021 at 16:04

Since the question is about cookies, an answer that is based solely of the GDPR would be incomplete.

The confusing facts are that:

  • It is the ePrivacy Directive which controls the use of cookies (“the Cookie Law”)
  • It is the GDPR that controls the data which cookies process.

The GDPR defines six grounds for keeping user data that include Consent, Contract, Legal obligation, Vital interests, Public task and Legitimate interests. But because of the ePrivacy Directive, it is Consent that is mandatory, much before Legitimate interests. This means that Legitimate interest must still require consent.

Even if the website deems processing to be necessary, legitimate interest must be weighed against the fundamental rights and freedoms of the users.

The GDPR highlights the following as specific types of processing that are considered legitimate interest:

  • Fraud prevention
  • Network and information security
  • Indicating possible criminal acts or threats to public security
  • Processing employee or client data, direct marketing and intra-group administrative transfers will probably also be considered legitimate interest.

Recital (47) of the GDPR says: “The processing of personal data for direct marketing purposes may be regarded as carried out for a legitimate interest”. But the word "may" here does not give the website carte blanche for keeping user data.

The website must balance its interests against the individual’s. If the individual would not reasonably expect the processing, or if it would cause unjustified harm, his interests override the website's legitimate interests.

Legitimate interest is actually pretty troublesome to use by a website. The website must document its justifications for using it, and must supply this documentation for any inquiry by users or the authorities. It must include details of its legitimate interests in its privacy information. It must also keep a record of its legitimate interests assessment (LIA), to help demonstrate compliance if required.

To that end, the UK’s data protection authority, suggests using a three-part test that includes the following:

  • Purpose test – is there a legitimate interest behind the processing?
  • Necessity test – is the processing necessary for that purpose?
  • Balancing test – is the legitimate interest overridden by the individual’s interests, rights or freedoms?

Having good answers available for all these three points is required to demonstrate legitimate interest. This rather heavy process should make a website think twice before claiming legitimate interest.


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