Contents:
1. What are Prolific ID’s?
2. Why do we record Prolific ID’s?
3. How do I set up my external survey tool?
4. How can I record Prolific IDs?
- URL parameters
- Securing the URL parameters
- What is ‘Secured External URL’?
- How do I use the ‘Secured External URL’?
- Why has this been implemented?
- A question in my study
- I don’t need to record these

What are Prolific ID’s?

Prolific IDs help identify participants who complete your study through an external provider. When participants are sent to your external survey tool of choice Prolific will add the following three IDs with the link, so that each participant is identifiable:

  1. Prolific PID - the ID that uniquely identifies a Prolific participant
  2. Session ID - the ID of the submission associated with that connection to the survey tool
  3. Study ID - the ID of the Prolific study associated with the submission

Why do we record Prolific ID’s?

As mentioned above, Prolific IDs help identify participants who complete your study through an external provider. Since Prolific collects demographic information about study participants, as a researcher you will need to link survey responses to this demographic data. Prolific IDs make this connection possible.

For API users, the three ID’s mentioned above can also be used to authorise access in the external survey tool. This can be done by calling the GET submission endpoint and validating the returned participant and study ids.

How do I set up my external survey tool?

To set up your external survey tool and use secure external URLs, check our integration guides and select your preferred tool.

How can I record Prolific IDs?

When setting up your study, you'll be asked how you want to record the IDs. There are three options: ‘URL parameters’, ‘a question within your study’, or ‘I don't need to record these’. Below is an explanation of what each option means and how to set them up.

URL parameters

To link participant demographic data from Prolific with your study submissions, you'll need to configure your external survey tool to capture unique IDs.

Each external survey tool set-up is different, check out our integration guides for more detailed information on how to set this up with your preferred tool.

Securing the URL parameters

If you’re looking for extra assurance that the URL parameters haven’t been tampered with in the transit from Prolific to the external survey tool, you can enable “Secure External URL” when creating the study.

This feature is only available to certain workspaces. However, if you’re interested please reach out to discuss enabling this for you.

What is ‘Secured External URL’?

  • When enabled, this setting allows Prolific to securely sign all URL parameters before redirecting participants to the survey tool. The URL will include a JSON Web Token containing these secured parameters.

How do I use the ‘Secured External URL’?

  • When the participant enters the survey tool, it will need to verify the JSON Web Token before authorising the participant to take the study.
  • Here are our API integration docs for what to verify in the JWT. It includes a new property on the create draft study endpoint with information on how to verify.

Why has the ‘Secured External URL’ been implemented?

Securing the parameters provides you with two key assurances:

  • The Prolific IDs are accurate and protected from tampering
  • The token expires after 2 minutes, enhancing security by preventing participants from reusing the URL after their initial eligibility check.

Using our ‘Secured External URL’ feature is mainly for, but not limited to, researchers who are building their own integrations/survey tools, and are looking to integrate their platform to Prolific.

A question in my study

Alternatively, you can include a question like "What is your Prolific participant ID?" directly in your survey. This response can then be used to link survey answers to the Prolific participant.

This method relies on participants entering their ID correctly—it's vulnerable to both honest mistakes and deliberate misuse. While some survey tools may not support query parameters, this approach can work for studies where 100% accurate participant linking isn't essential.

I don’t need to record these

If you choose not to record Prolific IDs using either of the option above, you won't be able to link survey responses to Prolific participants, access their demographic data or reject poor quality submissions. Please consider this choice carefully, as you cannot reverse this decision once the study has been published.

To change it once published, they would have to stop the study, duplicate it, change the setting and publish the duplicated study.