Frequently Asked Questions

About Omnipedia

What is Omnipedia?

Omnipedia is an offline encyclopedia app that lets you read high-quality articles without an internet connection. It’s designed for students, travelers, researchers, or anyone who wants fast, distraction-free access to knowledge – even in remote or low-connectivity environments. It’s great for all those random moments when you don’t have internet access.

To make this possible, we reprocess and compress all articles available on Wikipedia into a compact package that will fit comfortably on your device. We do this in full compliance with Wikipedia’s Creative Commons license, and while access to Omnipedia is only available on a subscription basis, the content itself remains free to use, share, and adapt under the same terms.

Why pay for Omnipedia, when Wikipedia is free?

We strongly support Wikipedia’s mission of free knowledge for everyone. What Omnipedia offers is an enhanced way to use Wikipedia’s rich content: offline access, private on-device search, fast incremental library updates, and a mobile-friendly reading experience. Our goal is to increase the freedom of Wikipedia articles by making them available in even more places, at even more times, and to even more people. Our subscription fees support the development and maintenance of this enhanced experience.

Do you collect any data from the app?

We do not routinely collect any personal information, even if you are a subscriber. We also do not collect any information or statistics about what you search for, what articles you read, or how you use the app. Your bookmarks and reading history remain on your device and you can rest assured that you will always have a completely private reading experience.

We do keep some logs of the number of library downloads and updates, and we temporarily log your IP address during the download process. However, we only use this information for normal service provision and it is not directly linked to your identity. Additionally, Apple provides us with some general statistics, such as the number of downloads and subscriptions from each country; but, again, such statistics are not linked to you personally.

You can find more information in our Privacy Policy.

Who runs Omnipedia?

Omnipedia is made by Recursive Ink, a small independent developer based in the UK.

Subscriptions

Why does Omnipedia require a subscription?

We think subscription-based pricing makes sense for three reasons:

  1. Omnipedia libraries are complex to create and maintain, and they are costly to store and distribute over the internet. Subscription revenue allows us to cover these ongoing costs in a way that is sustainable.
  2. Subscriptions keep us accountable to you and ensure that our interests are always aligned with yours. We do not make decisions based on short-term profiteering or the interests of advertisers.
  3. With ongoing revenue, we can continue to improve the Omnipedia app to give you an excellent reading experience that stays up-to-date with the latest features of iOS and continues to work on the newest devices.

How much does Omnipedia cost?

We offer a single annual subscription plan – no confusing tiers, upsells, or hidden charges. See the App Store or the app itself for pricing in your region and currency.

Can I try the app before purchasing a subscription?

Yes. The Omnipedia app is free to download and comes bundled with a demo library of 100 articles so that you can quickly try it out. The demo has no time limit – you can use it for as long as you like. Once subscribed, you can download complete libraries containing millions of articles.

Can I still use Omnipedia if I decide not to renew my subscription?

Yes. The libraries that you’ve already downloaded to your device will continue to work indefinitely. However, if you do cancel your subscription, you will no longer have access to library updates, so the articles on your device will gradually become stale and inaccurate over time. In addition, you will not be able to re-download a library, which may present a problem if you upgrade to a new device or if you want to temporarily remove the library to free up some space. In cases such as these, you will need to make your own backup. See the Technical Details section of this FAQ for more information on this process.

How do I cancel my subscription?

Your subscription is managed entirely by the App Store and follows standard App Store policies. You can cancel your subscription at any time up to 24 hours before your renewal date. You will continue to have full access to Omnipedia, including library updates, until your subscription expires. You can cancel within the Omnipedia app, from the App Store app, from iOS Settings, or at account.apple.com.

Article Content

Do you make any changes to the original Wikipedia articles?

Our goal is to give you offline access to the Wikipedia articles that you love, while keeping the on-device storage footprint as small as possible. This means we need to make some trade-offs. While we do not make editorial changes to the original Wikipedia articles themselves, we do remove some components of articles in order to achieve smaller file sizes and faster downloads/updates. In deciding which parts of articles to remove, we are guided by three questions:

  1. Is the article component good “value for money”? For example, images are extremely large relative to their informational value. A single image file can be tens or hundreds of times larger than the entire article text.
  2. Is the article component actually useful in an offline context? For example, external links and references are typically not very useful when you are offline because you cannot follow the links without an internet connection.
  3. Can the article component be reliably processed and tracked over time? For example, info boxes are hard to convert into static offline articles because of Wikipedia’s complex templating system, which allows for information in one article to be dynamically incorporated into another.

With these principles in mind, we retain the following article components:

And we remove these components:

Tables are currently not included, but we are working on support for tables in a future update.

But remember: The original Wikipedia article is always just one tap away if you ever need it (and have an internet connection).

Which languages is Omnipedia available in?

Currently, Omnipedia has support for four editions of Wikipedia: English, French, German, and Japanese. Tracking the ongoing changes to millions of articles and producing monthly incremental updates is a complex challenge on our end, not least because each language edition of Wikipedia has its own individual characteristics that require careful handling. However, we want to make Omnipedia available to as many people as possible, and we are gradually rolling out support for more languages.

Can I use multiple languages?

Yes – your subscription allows you to download as many libraries as you want, so long as you have sufficient storage space.

Can I share Omnipedia libraries and articles with others?

We make a distinction between article content (Markdown-formatted articles derived from Wikipedia) and Omnipedia libraries (Codex container archives used to distribute that content).

Article content is licensed under the Creative Commons Attribution-ShareAlike 4.0 International License (CC BY-SA 4.0). You are free to share, adapt, and reuse this content, provided you follow the terms of that license. In particular, you must provide appropriate attribution to Wikipedia contributors and Omnipedia, and you must license any derivative works under the same terms.

Omnipedia libraries are under copyright and may not be redistributed in their packaged form. However, as a licensee of CC BY-SA content, you are permitted to extract and reuse the articles contained within these libraries, subject to the terms of that license (as described above).

The Omnipedia app allows you to export individual articles in Markdown or HTML format. For technical users who would like to extract many or all articles from a Codex archive, we provide an open-source Python implementation of the Codex decoder to help you do that.

You can find more information in our Terms of Service.

How do I report erroneous information or problematic content?

If the issue is with the original Wikipedia article, it is best to report the problem directly to Wikipedia. In many cases you can edit the Wikipedia page yourself, or you can discuss the issue through Wikipedia’s “Talk” pages. Once the issue is fixed in Wikipedia, it will be mirrored in Omnipedia in the next monthly update cycle.

If you discover an issue that is specific to Omnipedia, such as missing or corrupted text, please use the “Report a Problem” option from the article in question, and then give a brief description of the issue. We do not make changes to Wikipedia articles, but we can fix things if they are not displaying correctly in Omnipedia. Please do remember, however, that certain parts of the original Wikipedia article, such as images and references, are removed from the Omnipedia version by design (as described above).

Downloads and Updates

How long does it take to download?

The Omnipedia app itself is very small (~12 MB) and can be downloaded from the App Store in seconds. A complete Omnipedia library is between 3 and 10 GB (depending on the language) and can typically be downloaded in less than an hour on most home internet connections. Once you’ve downloaded a library, future monthly updates are much smaller and can usually be installed in five to ten minutes (depending on the the language, network speed, and processor speed).

How often do you publish updates?

We publish library updates once per month, typically near the end of the month (25th—28th).

Do I have to download every update?

No. You can choose when to perform updates and how often you want to perform them. It’s also possible to skip updates. For example, if you currently have the April snapshot installed, it is possible to update directly to the August snapshot without installing each of the intermediate snapshots – May, June, and July.

I got the message “Insufficient storage capacity to perform update” but I have plenty of space.

During the update process, an entirely new copy of the library is created. Once the update is complete and the new copy of the library has been verified, the original copy of the library is then removed. This is to prevent the original library getting into a corrupted or partially complete state (e.g., due to an abrupt termination of the app or a loss of internet connection).

For example, if you have a 10 GB library installed and you want to update to a new version. You’ll need at least 10 GB of free space (i.e., in addition to the 10 GB already consumed by the library). Once the update process has completed, you’ll get this 10 GB back.

If you’re not able to free up sufficient space on your device to perform an update, one option is to delete the library and reinstall it. This will allow you to get the latest version, but it will take a lot longer to download. If you choose to do this, you can select the “Delete Library Archive” option, which removes the underlying archive files without deleting your bookmarks and history.

Technical Details

Which platforms is Omnipedia available on?

Omnipedia is currently available on iPhone and iPad. We also want to make Omnipedia available on other platforms too, but we can’t make any promises at the moment as to when this support is likely to arrive.

What file format does Omnipedia use to store articles?

Omnipedia libraries are stored in an archive format called Codex that was developed by the Omnipedia team for the express purpose of distributing large-scale encyclopedic content. The Codex format uses block compression to achieve a good balance between compression ratio and random access speed, and archives are broken up into many “shards” to allow for fault-tolerant, resumable downloads. The Codex format permits title searches and individual article access without decompressing the entire library on device, and it supports incremental updates, so that articles can be updated without being re-downloaded in their entirety. The articles themselves are stored in Markdown, a modern, lightweight, plaintext markup format that is human- and machine-readable.

How are the articles chosen on the Explore screen?

The articles recommended on the Explore screen are chosen pseudorandomly, with greater weight given to articles that appear more interesting based on various heuristics. However, we are working on an improved algorithm to select the articles in a more personalized way that takes your previous reading history into account.

How does search work in Omnipedia?

Because Omnipedia libraries are stored on your device in a compressed state, it is not feasible to perform a complete search of all article content in real time. Instead, when you perform a search in Omnipedia, you get a list of articles whose titles begin with your search query.

For example, if you search for “united”, you will find articles like “United Kingdom”, “United Nations”, and “United States”, but you will not find articles like “Manchester United”.

However, the search index does include all of Wikipedia’s redirection pointers. For example, “UK” redirects to “United Kingdom” and “UK Parliament” redirects to “Parliament of the United Kingdom”. So, even if you don’t know the exact title, you may be pointed to the right article anyway.

If your search doesn’t bring up any results, try to imagine what the Wikipedia title might be and rephrase accordingly. Once you’ve opened an article, there is a separate in-page search feature that allows you to search for snippets of text within the article.

Does Omnipedia sync between devices?

Omnipedia does not currently sync between devices, although we are looking into ways that we can support this in the future. You can use Omnipedia on multiple devices linked to your App Store account, but each copy of Omnipedia will function independently.

Are Omnipedia libraries backed up to iCloud?

Omnipedia libraries are not backed up to iCloud because doing so would consume a lot of your iCloud storage space. Indeed, if you’re on the free iCloud tier (5 GB), you wouldn’t have sufficient space to perform a backup anyway. However, your bookmarks and reading history are backed up to iCloud, and you can re-download Omnipedia libraries if necessary (for example, if you upgrade to a new device).

How do I make a personal backup of the library?

If you connect your device to a Mac or PC, you will be able to see the underlying Codex files associated with the Omnipedia library. These files will have names like “enwiki_20250701_complete.000.codex” numbered from 000 to 255. You can transfer these files to your computer by following the steps described in this Apple support article for Mac or this Apple support article for Windows.

To restore from a backup, you can simply copy the same files back to your device, being sure to copy them to the Omnipedia app. Note that the Omnipedia app will only recognize Codex files for libraries you installed during your subscription period. If you delete the library from the Omnipedia app, or if you delete the app itself, there will no longer be a record of which libraries you had installed and the app will not recognize the Codex files.

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