This guide walks you through enabling, expanding, and disabling fast signing for an API user via the Fireblocks Console.
Before you begin
Verify the following:
- API user paired with Co-signer: The API user must be paired with an API Co-signer (SGX, AWS Nitro, or GCP).
- Co-signer version 2026.03.02 to enable MPC-BAM. If your Co-signer's version is below the requirement, you won't be able to enable fast signing until you upgrade.
- Co-signer version 2026.09.16 to additionally enable MPC-FROST for EdDSA chains (Solana, Cardano, Polkadot). If your Co-signer is below this version, you can still enable MPC-BAM now and add MPC-FROST after upgrading.
Enabling fast signing for an API user
- In the Fireblocks Console, go to Developer center > Co-signers.
- Find (and expand, if necessary) the Co-signer with the API user you want to configure, then select More actions for that API user.
- Select the fast signing option shown — Enable fast signing, Fast signing settings, or Disable fast signing — depending on the API user's current state and your Co-signer's version.
- Review the dialog — it names which protocol(s) the action applies to — and confirm.
After confirming, keys are automatically provisioned in the background for each protocol covered by the dialog. You'll see a "Processing" status indicator next to the API user. Key provisioning typically completes within a few seconds.
During provisioning, your API user continues to use MPC-CMP for signing. There is no downtime.
Verifying fast signing is active
Once key provisioning completes, a lightning bolt icon (⚡) with an algorithm label appears under the API user's name in the Paired API users list, and a confirmation message appears:
- ⚡ ECDSA — fast signing is enabled for MPC-BAM only (Bitcoin, Ethereum, EVM chains).
- ⚡ ECDSA & EdDSA — fast signing is enabled for both MPC-BAM and MPC-FROST.
Disabling or removing fast signing
You can revert to MPC-CMP for an API user at any time:
- If only MPC-BAM is enabled, select More actions > Disable fast signing, then confirm.
- If MPC-BAM and MPC-FROST are both enabled, select More actions > Fast signing settings > Remove fast signing entirely, then select Save changes.
When reverted, the API user immediately reverts to MPC-CMP signing for all algorithms. Your MPC-BAM and MPC-FROST keys are retained but not used.
Troubleshooting
Fast signing option not available
Possible causes:
- API user not paired with an API Co-signer
- Co-signer version below 2026.03.02 (you'll see an "Upgrade Co-signer to enable fast signing" indicator)
Solution:
- Upgrade your Co-signer to version 2026.03.02 or higher
- Ensure the API user is properly paired with the Co-signer
The "More actions" option doesn't look like what I expected
The exact option and dialog depend on the API user's current state:
- No fast signing enabled, Co-signer meets both the MPC-BAM and MPC-FROST version requirements → Enable fast signing turns on both protocols together.
- No fast signing enabled, Co-signer meets only the MPC-BAM version requirement → Enable fast signing turns on MPC-BAM only; the dialog notes MPC-FROST becomes available once you upgrade.
- MPC-BAM already enabled, Co-signer now also meets the MPC-FROST version requirement → Fast signing settings lets you add MPC-FROST or remove fast signing entirely.
- MPC-BAM already enabled, Co-signer doesn't meet the MPC-FROST version requirement → only Disable fast signing is shown; upgrade your Co-signer to unlock Fast signing settings.
Key provisioning is stuck in "Processing"
Possible causes:
- Co-signer is offline or temporarily unavailable
- Network connectivity issues
Solution:
- Check that the Co-signer status shows "Online" in the Console
- Wait a few minutes and refresh the page
- If the issue persists after 10 minutes, contact Fireblocks Support