> ## Documentation Index
> Fetch the complete documentation index at: https://e2b.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# How do I increase my concurrency limit?

You can raise your number of [concurrent sandboxes](/docs/billing#plans) by purchasing self-serve concurrency add-ons from the [dashboard billing tab](https://e2b.dev/dashboard?tab=billing).

For higher limits at lower prices, commit to a minimum monthly usage for a year on the [Enterprise plan](/docs/billing#plans) by [contacting sales](mailto:enterprise@e2b.dev).

<AccordionGroup>
  <Accordion title="How much concurrency does each add-on add, and what's the self-serve maximum?">
    Each add-on adds 500 concurrent sandbox slots. On the Pro tier, you can scale this way up to 1,100 concurrent sandboxes. To go higher, you need an Enterprise plan.
  </Accordion>

  <Accordion title="What's the per-unit pricing?">
    \$500/month per add-on (500 slots), charged on top of your usage bill.
  </Accordion>

  <Accordion title="Does the increase take effect immediately?">
    Yes. The higher limit applies as soon as you purchase the add-on, with no provisioning delay.
  </Accordion>

  <Accordion title="Can I scale the add-ons back down later?">
    Yes. Add-ons are billed monthly and are non-refundable, but you can remove one to stop future charges, so you are not locked in beyond the current billing period.
  </Accordion>

  <Accordion title="How is a mid-cycle purchase billed?">
    The dashboard shows the exact amount you will be charged before you confirm the purchase.
  </Accordion>
</AccordionGroup>