> ## Documentation Index
> Fetch the complete documentation index at: https://www.helius.dev/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Preprocessed Transactions FAQs

> Answers to common questions about the preprocessedSubscribe endpoint

## Using Preprocessed Transactions

<Accordion title="Can you update preprocessed subscription filters live?">
  No, the filter is fixed by the initial `preprocessedSubscribe`. To avoid a gap we recommend opening a second connection with the new filter, wait for its subscription acknowledgement, and then cut over your service to the new filter.
</Accordion>

<Accordion title="Is the preprocessedSubscribe concurrent subscription limit per API key or account?">
  The 10 concurrent connection limit is enforced per Helius project. Creating a second API key for the same project would share the same 10-connection limit.
</Accordion>

## Need More Help?

<CardGroup cols={2}>
  <Card title="Preprocessed Transactions" icon="layer-group" href="/docs/preprocessed-transactions/overview">
    Learn about using Preprocessed Transactions
  </Card>

  <Card title="preprocessedSubscribe API Reference" icon="headset" href="/docs/preprocessed-transactions/preprocessed-subscribe">
    Learn about subscriptions, filters, and get examples
  </Card>
</CardGroup>