To make Deployments, the Vercel platform must first build a project. Building projects in the cloud is much faster than building locally, however, it is possible for builds to get queued when making multiple deployments at the same time.
By default, Vercel accounts have access to a single concurrent build slot. This means that only a single deployment can be building at any one time unless additional concurrent build slots are purchased. The maximum number of concurrent build slots is dependent on the account plan, this is shown below:
- Hobby (1)
- Pro (12)
- Enterprise (no limit)
If the number of builds to process is greater than the number of concurrent build slots available, some of these builds will be queued.
It is not possible to increase the number of concurrent build slots available for Hobby accounts, if your project would benefit from additional build slots, you may wish to consider upgrading to a Pro team plan.
Additional concurrent build slots can be purchased for Pro team plans from the Vercel Dashboard. To do so, select the Pro team you wish to add the additional build slots to from the team picker in the header. Then, click "Settings" and select the "Billing" section.
From the "Billing" section, find the fieldset labelled "Concurrent Builds" and enter the total number of build slots required before clicking "Confirm". The fieldset is shown below: