Guides

The index tells you what each tool is and what it costs. These go a layer down, into the two questions a feature list cannot answer: whether a tool does what its wording implies, and how to check for yourself.

• Which PDF tools really redact

  Some tools delete the content you mark and some only draw over it, and the two look identical on screen. This is how to tell them apart, which tools do which, and how to check a document yourself in about ten seconds.

• Checking a PDF for accessibility

  What PDF/UA, WCAG, the Matterhorn Protocol and Section 508 actually are, why checking a document is not the same as fixing it, and which tools check, which repair, and which build tagged output in the first place.

• Which PDF tools keep your file on your machine

  Offline PDF tools, and the difference between a tool we watched keep the file on the device, one whose vendor claims it does, and one that sends it to a server. Which tools are which, and how to tell without trusting anybody.

• Open source PDF tools, and what their licences require

  Open source is not one thing. Some of these are permissive, some are copyleft, and seven are AGPL, which reaches through a network service and obliges you to publish source. Which tools sit in which group, with each licence as the record holds it.

Where these come from

Every verdict in both guides is generated from the same records as the tool profiles, so a corrected price or a reclassified tool changes the guide as well. Where a claim rests on our own testing rather than on a vendor's documentation, the guide says which, and each profile carries the full method.

Neither guide is sponsored, and no tool can pay to appear in one. How listings and sponsorship work .