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Licenses of Pdftools products

A valid license key is required to use the Pdftools products without limitations. Some products allow you to try them without a license key with watermarked results. See the list below for more details:

  • Pdftools SDK: Watermarked results without a valid license key. Use a valid license key to remove the watermark.
  • Conversion Service: Use a valid license key to try or work with the product.
  • PDF Viewer SDK: Watermarked results without a valid license key. Use a valid license key to remove the watermark.

Other shell tools and SDKs:

  • PDF Toolbox SDK: Use a valid license key to try or work with the product.
  • 3-Heights SDK: Use a valid license key to try or work with the product.

Do you need a full product license, a new license key, or an upgrade to your current license, or do you want to ask us anything else? Get in touch with our team through the Contact page.

Identifying a license key

This section helps you identify the product for which a specific license key can be used. To identify the product, compare your license key with the following examples:

  • Value PDFSDK indicates that the license key belongs to Pdftools SDK.
  • Values such as V1 and V4 change depending on the release version.
  • To correctly validate the license key, include the angle brackets (<>) at the beginning and the end of the license key.

License key activation

The process of activating and using a license key varies depending on the Pdftools product or version. See the respective product pages for detailed license information:

Frequently asked questions

Questions commonly asked about licenses:

Error activating license (...) License already activated 1 times

Check that you haven't activated the license already on another machine. If so, deactivate the license on that machine. To deactivate a license, see Deactivation section in Technical Note: License Keys.

If the error persists, contact Pdftools Technical Support.

The license added in the License Manager stops working. A red cross appears and the software doesn't work.

Some Pdftools licenses need to be activated. The license works for approximately 10 days without activation. The date after which it requires activation is displayed in the License Manager in "Activation necessary starting...".

To activate a Pdftools license for PDF Toolbox SDK and PDF Viewer SDK, see License activation.

To activate a 3-Heights product license, see License activation.

Error connecting to the licensing server

Pdftools SDK
Check your network connection. If the SDK is unable to connect to the licensing server, the license (and the product usage) is blocked. To be able to activate licenses and use the product offline, you must have set up the Licensing Gateway Service.

PDF Toolbox and PDF Viewer SDK
If the License Manager is unable to connect to the Licensing server, you can update, activate and deactivate the license offline. See Offline usage.

If you use a proxy server, ensure that the proxy allows connections via HTTP CONNECT to and add the license server URL to an allow list in your firewall.

The licensing server returned an error: 301 Moved Permanently

You are using an old version of the License Manager (older than, which doesn't use HTTPS.

Update to the latest version of the License Manager and try to deactivate, activate, and update the license again.

Error updating the license key in the License Manager

Check that:

  • The license key is still active for the product and hasn't expired. Evaluation licenses expire after 30 days.
  • The format of the license key is correct for the product. See Identifying a license key section.
  • The license hasn't been installed on another machine. Otherwise, you need to deactivate the key on another machine before you can add it to the new machine.
  • The license hasn't already been installed on a machine. An Error storing key: File exists message appears.
Error storing key: The license key has been manipulated
  1. A typographical error in the license key. Try typing the key again. Make sure no blanks are added when copying the key.
  2. Example key (1-XXXXX-XXXXX-XXXXX-XXXXX-XXXXX-XXXXX-XXXXX) is used. The X character represents a numerical value and is not an active license key.
  3. Download the key from My PDF Tools Portal and add/store it on the machine.
LIC_E_FEATURE error: The use of this function requires additional features activated in the license key

Some Pdftools products include optional features that require activation in the license key. If you receive this error, contact Pdftools Sales to request the feature.