Nimbata gives you four ways to block unwanted or spam callers.

Use whichever method best fits the type of spam you're dealing with.

Method 1. Block a specific number from the Spam Callers list

Use this to block a single caller ID you've already identified as spam.

• Go to Data Tools > Spam Callers.
• Click the + button.
• Enter the caller ID and click Add.

The number is now blocked and will appear in your blocked callers list.

Method 2. Block a number directly from the Calls log

Use this when you spot a spam number in your activity log.

• Go to Activity > Calls.
• Search for the caller ID in the search bar and select the correct date range.
• Click the arrow to expand the call details.
• Click Add to call spam numbers.

Method 3. Block entire caller ID prefixes using a call flow

Use this to block all calls from a specific area code, country code, or number pattern.

Step 1. Create a new call flow

• Go to Tracking > Call Flows.
• Click + Add.

Step 2. Add the Caller ID Prefix filter

• Click the + button on the canvas.
• Select Caller ID Prefix from the Filters menu.

Step 3. Enter the prefix and route it to Hang Up

• Type the prefix you want to block.
• Click the + below that branch and select Hang Up.

Step 4. Route all remaining callers normally

• On the remaining-callers branch, add a Dial action to your destination number.

Method 4. Use Greeting + Keypad Entry to filter spam naturally

Use this to silently deter robocalls without blocking legitimate callers.

Any caller who doesn't press a key is hung up on, while real callers proceed.

Step 1. Create a new call flow and add a Greeting

• Go to Tracking > Call Flows.
• Click + Add.
• Add a Greeting that instructs callers to press a key to continue. E.g. "Press 1 to connect."

Step 2. Add the Keypad Entry action

• Click the + below the Greeting.
• Select Keypad Entry from the Filters menu.

Step 3. Route the matching key to Dial, and Remaining Keys / No Input to Hang Up

• On the branch for the correct key press (e.g. 1), add a Dial action.
• On the Remaining Keys / No Input branch, add Hang Up.

Remove a number from the block list

• Go to Data Tools > Spam Callers.
• Select the number.
• Click the red bin icon and confirm.

Detailed Guide: How to use the caller ID prefix filter for Geo-routing

Detailed Guide: How to block calls from specific countries

Detailed Guide: How to add a keypad entry (IVR)

Updated on: 01/04/2026