My browser is saving a copy of the web pages I visit on my computer. How is that not copyright infringement?

in this answer I read:

I would hazard a guess that displaying an HTML webpage online is implicitly allowing others to read that code

How does that imply that you can make a local copy, when a web page includes a copyright note, or does not mention copyright at all (in which case standard copyright rules apply)?

I suspect that the only possible way out would be stating that digital text is not the same thing as printed text and therefore the same rules should not apply, but we are constantly told the opposite, aren't we?


I'm adding some quotes from the only answer and comments below, to bring more elements for further answers that I hope will come, since I'm still not convinced that this situation makes completely sense.

It has been pointed out that

Fortunately I don't need to be convinced, as I'm not a judge on a relevant case (Jon Story. I changed "you" from the original comment to "I")

And that's totally true, so I feel like reassuring that my question comes only out of my couriosity and noone needs to answer if they don't wish to satisfy that.

I'd like to receive an answer that copes with some alternative views seen here, possibily making me understand which one is right (or more logical, or more convincing). I don't mean to make this question become too broad, so we are still dealing with the original problem: whether browser cache violates (US and EU) copyright laws in theory. I do hope this is a good subjective question.

Please be aware that I believe the term Intellectual Property, which appeared in the comments, to be misleading. It refers to patents, trademarks, copyright and other stuff, while we're just discussing about copyright here.

Quotes from answer and comments:

  • Copyright is not about copying, it is about use (Jon Story)

  • Many misconceptions are based on copyright being about use. Copyright is not about use, it is about copying (Marcks Thomas)

  • To expand on the point about use, not copying, being the main issue, it would be a violation of copyright to take a BD and project it onto a large screen and charge money for people to watch it. I didn't copy the disc, just played it for profit (or even if i didn't charge, as a public performance) and I'd go to jail (Andy)

  • You wouldn't say the optical fiber the data was sent through was copying the data? (kasperd)

  • In order to read printed text, your eyes make a copy of that work (in a different format, made up of neurons firing in your brain) (Jon Story)

  • routers don't copy the data in full. They process one packet at a time, which by no means is enough to contain the full work. A packet is more comparable with a citation, than a copy of the work. (kasperd)


I'm going to start a bounty on this question. Here I add the parts of the current answer (Jon Story's) I'm less satisfied with:

Because you are not duplicating the content or re-publishing it

I'm clearly doing the first of these two things.

The web page is publicly available anyway (or at least, accessible by you), so you have permission to read it: copyright is about whether you have permission to access and read the file, not about whether you have permission to make a copy of the file as part of the technical process of accessing and reading it.

I'm almost certain that copyright is not about the permission to read and access the text, but about the permission of making copies, modifying, redistributing and other stuff like that. For instance, I don't think you can make a copyright note that does not allow reading your content. Is fair use the key point here? That may be, and in the comments I was almost convinced. However, I've never known that fair use could justifiy copying the entire text. They won't let me photocopy an entire copyrighted book for personal use, I guess.

  • 7
    Well technically every server and router between you and the site are making copies.
    – Andy
    Commented Sep 1, 2015 at 1:57
  • 4
    @Andy: Right, so we have the same issue there... Commented Sep 1, 2015 at 5:14
  • 1
    @kasperd Well, you don't really know that there aren't any other servers (proxies) in play. And some routers get every package, like the one at your ISP, but even the ones that don't, you're still not allowed to copy and sell a single chapter from a book without the rest; I'm fairly certain that would still be infringement. Its not as clear cut as you're trying to make it sound, and ultimately how much infringement there is would be decided by a judge, if it got that far.
    – Andy
    Commented Sep 9, 2015 at 15:15
  • 1
    @Andy I do not know whether the serving infrastructure chosen by the copyright holder involves any proxies, but I would consider those outside the scope if this question, because any copies made by those proxies would be authorized by the copyright holder. I know an ISP could deploy a proxy with host of their customers not noticing, but I am one of those who would notice, and I have yet to experience an ISP pulling such a trick.
    – kasperd
    Commented Sep 9, 2015 at 15:25
  • 1
    Why dwell on caching? Don't you make a copy of the page on your screen, or paper (if you prefer to print the article and read it offline)? Commented Oct 24, 2020 at 19:07

6 Answers 6


I'm only going to consider US perspectives, which may or may not answer your question entirely. Also, I'm not going to address the guesses in other answers because, and except to say, they don't appear to be based in law, but rather (mis)understandings of law.

17 U.S. Code § 512 provides protections for service providers when providing content, online. This expressly includes caching. In Viacom Int'l, Inc. v. YouTube, Inc., 676 F.3d 19 (2d Cir. N.Y. 2012) at 39, the Court held that to exclude these functions from the safe harbor would remove protections for service providers under subsection (c).

The answer, however, lies in Perfect 10 v. Google, Inc., 416 F. Supp. 2d 828 (C.D. Cal. 2006), in footnote 17, at 852:

  1. Local caching by the browsers of individual users is noncommercial, transformative, and no more than necessary to achieve the objectives of decreasing network latency and minimizing unnecessary bandwidth usage (essential to the internet). It has a minimal impact on the potential market for the original work, especially given that most users would not be able to find their own local browser cache, let alone locate a specific cached copy of a particular image. That local browser caching is fair use is supported by a recent decision holding that Google's Click for Enhanced Coverage Linking Searches own cache constitutes fair use.

The case referred to is Field v. Google, Inc, 412 F.Supp. 2d 1106 (D. Nev. 2006).

Although the Perfect 10 v. Google, Inc. was overturned on appeal - Google was permitted to utilise thumbnails in their search pages - and the above is merely obiter, it is the closest to a ruling on browser caching I have been able to find.

In short: Google's caching has been found to be fair use. It is unlikely that your local cache would not, as it is generally done automatically.

  • 7
    You can't violate copyright, at least in the United States, by using a work in the ordinary and expected way. So you can color in a coloring book even if it creates a derivative work. Commented Apr 22, 2023 at 17:13

I'll consider the EU perspective, which is that browser caching is legal.

Article 5(1) of Directive 2001/29/EC, the Copyright Directive, states that:

Temporary acts of reproduction ... which are transient or incidental [and] an integral and essential part of a technological process ...1 shall be exempted from the reproduction right.

Article 5(5) specifies that this exemption only applies

... in certain special cases which do not conflict with a normal exploitation of the work or other subject-matter and do not unreasonably prejudice the legitimate interests of the rightholder.

On June 5th, 2014, the CJEU ruled that browser caches, and indeed also the on-screen copies do in fact satisfy the provisions for an exemption under Article 5. They summarized their ruling as such:

Article 5 of [the Copyright Directive] must be interpreted as meaning that the copies on the user’s computer screen and the copies in the internet ‘cache’ of that computer’s hard disk, made by an end-user in the course of viewing a website, satisfy the conditions that those copies must be temporary, that they must be transient or incidental in nature and that they must constitute an integral and essential part of a technological process, as well as the conditions laid down in Article 5(5) of that directive, and that they may therefore be made without the authorisation of the copyright holders.

1) The CJEU did not consider this portion of Article 5(1) as these conditions were already considered to be satisfied in the case at hand. It states that acts of reproduction are only exempted when their

... sole purpose is to enable:

  • (a) a transmission in a network between third parties by an intermediary, or
  • (b) a lawful use

of a work or other subject-matter to be made, and which have no independent economic significance.

Browser caching might then be illegal when done as part of an illegal act, or the use is commercial, but these cases are probably not what the question was meant to address.


I believe this question is much simpler than it appears. The browser can cache pages because it was given explicit permission to do so.

You see, when you're requesting a web page from a server, then together with the page itself you and the server exchange some additional meta-information about the page, called HTTP Headers. One of those headers, Cache-Control describes what the server allows the client to do with respect to caching. So if the server sends

Cache-Control: no-store

then the client won't store the page and no copyright violation occurs. If the server, however, says

Cache-Control: public

(or other value with a similar effect), then the server effectively grants you a permission to store the copy of the page in a cache. Thus, no copyright violation occurs in this case either.

  • Interesting. However, many pages give contradictory directives in plain language somewhere on the site (e.g. copyright information, terms of service), with statements such as "you may not make any copies of the site content without prior written consent." If such a contradictory statement appears, which one takes precedence? The plain language statement "may not make any copies" or the "Cache-Control: public" directive (i.e. 'you may make copies for caching purposes only')?
    – Brandin
    Commented Sep 19, 2022 at 15:09
  • I would consider the cache control directive a "prior written consent". It's prior because it technically is transmitted first and it's obviously written (albeit in technical language).
    – Marcel
    Commented Apr 21, 2023 at 6:11
  • 3
    In the US, unclear or conflicting contract terms are resolved in favor of the party that didn't write the contract by default. Commented Apr 21, 2023 at 13:27
  • Cache-control headers are optional, and the default is that the browser will cache the page; the header is used to request that the browser limit caching (so that if the site updates the page, the user won't be stuck forever with a stale version). That doesn't sound like "giving permission" to me.
    – Barmar
    Commented Apr 18 at 0:48

Because you are not duplicating the content or re-publishing it. Copyright is fundamentally about permission.

Copyright covers the use of other people's work without permission, or passing their work off as your own without permission, or using their work in a way which you do not have permission to use it.

A cache does neither of those things: all it does is store a (temporary) copy of the file to aid (speed up) retrieval if the file is requested a second time... it does not allow you to do anything differently, only to view the same file as you were able to view anyway. The permission for the computer system to make copies of the file for this sole purpose is implicit in the fact that the webpage is being delivered via this medium. If you had permission to view the file once, you presumably have permission to view it again: and if you don't, the cache would (should) clear that file anyway during the second request.

The web page is publicly available anyway (or at least, accessible by you), so you have permission to read it: copyright is about whether you have permission to access and read the file, not about whether you have permission to make a copy of the file as part of the technical process of accessing and reading it.

Note that even without a cache, your computer still makes a copy of the file in memory to even be able to display it on your screen.

In order to read printed text, your eyes make a copy of that work (in a different format, made up of neurons firing in your brain), and you even make a long-term copy of some of that work in your long term memory. Fundamentally, these are no different: they are simply the means of transferring the content from the medium it is presented, to your consciousness. A book does not have state that you have permission to read it using your eyes, nor does a web page have to give permission to make temporary digital copies for the purpose of transferring it.

  • The point of the cache being cleared when my permission is no longer valid is the only one that could convince me. The rest of your explanation doesn't: I am indeed duplicating the content. Plus, your reasoning could apply to a photocopier and a borrowed book, it's just a matter of scale. I'll think about your answer in depth, thanks. Commented Sep 1, 2015 at 13:38
  • 6
    Fortunately you don't need to be convinced, as you're not a judge on a relevant case... but actually most copyright laws do allow photocopying for reasonable use (ie to make it easier for you to temporarily view a particular few pages, or blow them up to be more visible) so if anything, I suspect you've just proven my point. I believe you're taking the "Copy" part of "Copyright" a little too literally. Copyright is not about copying, it is about use.
    – Jon Story
    Commented Sep 1, 2015 at 13:40
  • @JonStory: Many misconceptions are based on copyright being about use. Copyright is not about use, it is about copying. Commented Sep 1, 2015 at 14:23
  • 7
    Actually if we're going to be pedantic, it's about ownership of intellectual property, and is neither specifically about use nor copying: however almost all breaches of copyright come about due to the use of someone else's intellectual property, of which some uses involve copying. In terms of the question, therefore, "use" of someone else's intellectual property is the primary concern, and whether that "use" breaches the relevant copyright law.
    – Jon Story
    Commented Sep 1, 2015 at 14:42
  • 1
    @supercat U.S. copyright law does not appear to restrict projection to particular types of projectors. §109(c) reads, "...the owner of a particular copy lawfully made under this title, or any person authorized by such owner, is entitled, without the authority of the copyright owner, to display that copy publicly, either directly or by the projection of no more than one image at a time, to viewers present at the place where the copy is located."
    – cjs
    Commented Aug 29, 2022 at 1:55

When a computer program is executed or even just installed on a computer, there are zillions of copies made. In the U.S., Title 17, Chapter 1, Section 117 acknowledges this reality and the impracticality of considering each of those copies an infringement by carving out limitations to the copyright holder's exclusive rights.

... [I]t is not an infringement for the owner of a copy of a computer program to make or authorize the making of another copy or adaptation of that computer program provided:

(1) that such a new copy or adaptation is created as an essential step in the utilization of the computer program in conjunction with a machine and that it is used in no other manner.... Section 117(a)

To understand whether this carveout applies, we have to understand whether the browser cache is making copies of a computer program.

A “computer program” is a set of statements or instructions to be used directly or indirectly in a computer in order to bring about a certain result. Section 101

The browser cache holds resources like HTML, CSS, Javascript. I think it's uncontroversial to assert those are computer programs.

Making copies of the resources is an essential step for the browser to run the computer programs that present web pages, so Section 117(a)(1) covers the browser cache's copies.

But ...

The browser also caches resources like images, audio and video clips, and even plain text files. Whether those are computer programs is perhaps not as clear cut.

Consider a word processing program that comes with a dictionary for the spelling checker feature. Just because that dictionary is stored in a separate file that is not itself a program, I believe that, for the purposes of the Section 117 carveouts, it would be considered part of the word processing program.

So I assert that all of the downloaded resources stored in the browser cache is a computer program or a portion of one.

But, but...

Hang on. Are the copies of the resources in the cache actually “copies”?

“Copies” are material objects ... in which a work is fixed ..., and from which the work can be perceived, reproduced, or otherwise communicated, either directly or with the aid of a machine or device. ... Section 101

The copies are therefore the storage devices themselves. The RAM, the hard drive, the SSD? Weird, but that doesn't seem to change anything. (I wonder if you could argue that the 100 unauthorized MP3 files on your flash drive constitute only a single infringement because the flash drive is a singular copy.)

But, but, but...

The browser cache stores stuff on the disc drive. It's a persistent copy. Making a temporary copy may be an essential step, but it's not essential for that copy to be persistent, right?

A work is “fixed” in a tangible medium of expression when its embodiment in a copy ... is sufficiently permanent or stable to permit it to be perceived, reproduced, or otherwise communicated for a period of more than transitory duration. ... Section 101

Caches, by their nature, are temporary, but that doesn't mean they won't persist data for more than a “transitory duration” (whatever that is).

I suppose the non-caching read buffer in a storage device (like a CD player) is just transitory, so it probably doesn't need to rely on a Title 117 carveout.

But that doesn't invalidate the conclusion. Title 117 doesn't say that copies must be temporary, just that they be essential.

  • The purpose of the browser cache is also to safe transmission time and cost when I view the same page multiple times. Say I look for a product on eBay. I look at multiple products, so I will be shown the same image ten times. The browser cache avoids nine of the ten downloads which is good for everyone. But it must be stored after the first download, otherwise it would have to be downloaded again the next time. It should be legal as long as it is only used to save downloads, or for playing a video without stutter.
    – gnasher729
    Commented Feb 12 at 9:26
  • Now on my computer I could open the browser cache and copy images from it. That should be treated same as any copying.
    – gnasher729
    Commented Feb 12 at 9:27
  • @gnasher729: That the cache reduces the number of downloads is useful, but I don't see how it's relevant to the legal question nor to my answer. Commented Feb 13 at 6:01

Fair use allows things to be used for "informational" purposes. What that means might be ascertained from how one tests a theory on what that means relative to its effect on the ecosystem.

I was on DeviantArt looking at a Matrix-esque picture of Mouse (from the movie The Matrix) and thought of it as copyright infringement. However, from an informational perspective it might not have been. The image was deleted, but that it was deleted does not necessarily entail that copyright law was broken (more specifically, that a negative effect on the ecosystem occurred, whereby I consider laws are never broken for persons were of the group of individuals with permission -- as per The Law -- to perform a particular act: But such does not necessarily entail it's a socially favorable act). Informationally, the picture from the movie was used...

Also, I interpret that images are code that are rendered by a computer program rather than being a computer program themselves.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .