We provide a range of dynamic services to help IWF Members safeguard their business from the upload, sharing, storage and sale of criminal child sexual abuse images and videos.
In 2025, more than 200 Members from across technology and internet-based industries used our services to prevent the exploitation of their services.
Our Members share our vision to put an end to child sexual abuse imagery online and trust the expertise of our analysts, our technical innovation and unique datasets.
Through IWF membership, organisations gain access to a curated suite of services designed to help them detect, remove and prevent child sexual abuse images. This include the IWF Hash List, URL List, Keywords List and Non-Photographic Imagery (NPI) List.
URL List
Our dynamic URL List provides a comprehensive list of webpages where we have confirmed the presence of child sexual abuse images or videos where the URLs link to or were found advertising such content. Since each URL (Uniform Resource Locator) identifies a unique webpage, image link, or website address, we can be precise about the exact location of the criminal imagery to ensure we never over-block a legitimate website.
We provide a list of these webpages to our Members who can then block or filter this material, affording greater protections to their users and to the children depicted in the criminal imagery.
Our analysts monitor these URLs daily to see if the sites are still online and remove those that aren’t from our URL list that same day. The list is updated twice a day, with URLs added and removed as content is identified or taken down.
During 2025:
- A total of 260,699, unique URLs were included on the list.
- On average, 1,212 URLs were added each day up from 1,129 per day in 2024 (an increase of 7%).
- The list contained an average of 6,923 URLs on any given day.
Criminal URLs on the list will depict a whole range of children, all ages, sexes and varying categories of severity of sexual abuse.
The role of takedown notices
We issue notice and takedown requests (also known as takedown notices) for websites hosted in the UK only. When content is hosted outside the UK, we notify the relevant international hotlines and law enforcement agencies to enable action to be taken locally. With agreement, our Hotline also supports the removal of international child sexual abuse material by following up on IWF notifications and contacting the hosting provider directly. This is an additional service we provide to limit the global availability of child sexual abuse imagery.
We conduct daily checks of the IWF URL List. If content is not removed within an appropriate timeframe, the IWF may issue removal notices directly to the relevant hosting provider in the country where the content is hosted. Once the criminal content has been taken down, the associated URLs are removed from the list to ensure it remains as accurate and up to date as possible.
Hash List
We use our own software, IntelliGrade, which generates a unique digital hash using advanced mathematical algorithms. These hashes are automatically created when our assessors complete the image-level assessment and the imagery is classified as criminal child sexual abuse. Each criminal image or video receives its own unique hash, which is then added to our Hash List. This list is regularly updated and shared with trusted partners across industry and law enforcement. We also support the safety tech sector to generate their own proprietary hashes using the images that we hold.
By integrating the list into their systems, organisations can automatically detect and block previously identified child sexual abuse imagery by matching uploads against our database of known hash values. This prevents the need to view, store or re-share the original content and prevents further revictimisation of the children depicted in this criminal imagery.
This rapid matching process prevents thousands of known criminal images from being uploaded to the internet again.
To date we have 3,224,085 criminal hashes on our list.
To learn more about our Hash List, visit our All-time hash data page.
Non-Photographic Imagery (NPI) URL List
Our Non-Photographic Imagery URL List identifies webpages hosting non-photographic representations of child sexual abuse, such as computer-generated images (CGI), cartoons, manga images and drawings.
URLs included on the list have been assessed by IWF analysts as breaching UK legislation. Prohibited non-photographic imagery is assessed under a separate legal framework (Section 62 of the Coroners and Justice Act 2009) to indecent images that fall under the Protection of Children Act 1978 and Section 160 of the Criminal Justice Act 1988.
- In 2025, we identified 439 URLs of non-photographic child sexual abuse imagery (a slight decrease from the 460 in 2024);
- 8,988 criminal images and videos were identified as prohibited.
- Only 1 of these was confirmed as UK-hosted content, for which we issued a notice requesting its removal.
While non-photographic imagery is outlawed in the UK, this isn’t the case for many other jurisdictions around the world.
If we find this content hosted in the UK, we issue a notice to the hosting provider, who removes it. For companies based elsewhere in the world, we’re unable to seek the removal of this content. Therefore, our NPI URL List provides a vital lifeline to support companies who want to prevent access to this content.
As of 2025, several international technology companies use this list to protect their services for their customers.
- At the end of 2025, 465 unique URLs of non-photographic child sexual abuse imagery were listed on the NPI URL List.
Keywords List
Our Keyword List brings together terms, phrases and codes developed by offenders to disguise and circulate criminal child sexual abuse material online. This intelligence is shared with IWF Members to:
- Support the identification and prevention of illegal content across their platforms and networks, and
- In moderation in environments such as chat services, social media, file or video sharing platforms and online forums, where coded terminology is often used to evade detection.
- It can also be used to filter search engine results, helping reduce the risk of users inadvertently encountering criminal content, and to flag files or domains that may require further investigation.
Our analysts are constantly identifying and evaluating new terminology to add to the list. Each month new additions are tested, with each term undergoing rigorous quality assurance before upload. The list continues to expand through our collaboration with law enforcement agencies and partners across the technology and internet industry.
Some readers may find the following descriptions distressing, please feel free to skip this section.
As analysts, we understand that some of the darkest parts of the internet exist on some of the world’s most popular platforms. We recognise the internet isn’t confined by borders, and the intelligence that we collect shouldn’t be either. Whether it be a new term popping up, a platform shift, or a special way offenders communicate, this global intelligence feeds directly into one of our most hands-on tools: the Keywords List.
The Keywords List isn’t static; it evolves as we learn, and only an analyst could understand the full context of some of the keywords we use. Keyword terms are not always obvious, they may be slang words or phrases that pertain to child sexual abuse in one language, but when translated to English mean something entirely different. Understanding keywords and the context behind them provides vital clues for how child sexual abuse material is shared online and this intelligence helps us fight its spread and accessibility.
Keyword intelligence is vital to the work we do in-house at the IWF and also to our wider impact through our Members. This year, the expansion of our keywords service has translated into fewer missed cues and a clearer path for our Members to intervene in the sharing of child sexual abuse that often occurs in plain sight. This service means intelligence evolves beyond stagnant information, and becomes tangible leads to follow, directly protecting children online regardless of their geographical location.
This year has highlighted that as global connectivity grows and reaches more parts of the world, having services and knowledge that span that breadth is essential. Our mission to protect children isn’t confined to those that speak English, and our international understanding has been key in spanning that reach, making sure no child is left behind regardless of where they are. Protecting children in all corners of the earth starts with analysts like us, and our tools reflect that.