429 errors usually appear when you've attempted to reserve a study, and is triggered if you've sent too many requests to our platform in a short period of time. For example, repeatedly trying to reserve a place on a study over a short space of time. This is a protective measure to ensure stable performance for all Prolific users.
Why this happens
Rate limits prevent any single user or integration from overloading our systems. You might see this error if you're:
Refreshing pages very frequently
Running automated scripts or integrations that make many requests
Performing bulk actions in quick succession
Using multiple browser tabs or devices simultaneously
How to fix it
Wait and retry
The simplest solution is to wait a few minutes before trying again. Rate limits typically reset within 1-5 minutes, depending on the action you were performing.
Avoid refreshing repeatedly
If a page is loading slowly, give it time to complete rather than refreshing multiple times. This can trigger rate limiting unnecessarily.
Do not use scripts or automations to reserve studies
The use of scripts, bots, or any sort of automation (excluding the official Prolific Assistant extension) to automatically reserve a study is strictly prohibited on Prolific, and is a breach of our Terms and Conditions.
Any participant found in breach of this condition will have their account terminated.
Still experiencing issues?
If you continue to see 429 errors after waiting and reducing your request frequency, contact our support team. Include details about what you were doing when the error occurred and whether you're using any integrations or scripts.