The difference between publish, start, and pause

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Throughout your experimentation, you can publish, start, and pause your experiments many times.


Publish saves and stages your experiment's changes. If you have not started or have paused the experiment, visitors cannot see your changes when you publish. A common use case for publishing changes to experiments that are not running is using Optimizely Experimentation's Experiment Scheduler to start your experiments.

If you publish changes to an experiment that is running (an experiment you have started but have not paused), visitors see your changes immediately. Optimizely Experimentation does not recommend publishing changes to a running experiment.


Start makes your experiment live to all visitors in your targeted audience and changes the experiment status to Running.


Pause stops your experiment and changes the experiment status to Paused. No new visitors see a paused experiment until you restart it.

You can use pause to send all traffic to the winning variation or re-launch an experiment that is not working correctly or delivering a poor experience.