Telephony and contact center

Check phone numbers, carriers and phone complaints in Talkdesk

Look up a caller or a customer number inside a Talkdesk flow and use the country, format and number type the numbering plan gives it to route the interaction.

Why the data matters in Talkdesk

A contact center decides where an interaction goes from the data on its first line. In Talkdesk that is often the caller number or the number a customer typed into a form, and when it is malformed or carries the wrong country, the flow falls through to a generic queue, a callback is dialed wrong or a record lookup comes back empty. A clean number at the top of the flow keeps queue choice, callbacks and customer matching honest.

What LookValid checks

LookValid checks for Talkdesk
Product	What it does here	Credits
Phone Numbering-Plan Validation	Normalizes a number to international format so a customer lookup finds the same record whichever way the number was typed. Returns the number type from the numbering plan, so a flow can skip toll-free and premium-rate numbers. US and Canada numbers usually come back as fixed line or mobile. It cannot confirm the line is reachable.	1 credit per valid number
Carrier Lookup (original carrier)	For US numbers, returns the carrier originally assigned the number block and its state and rate center. A number that has moved to another carrier still shows the original one.	1 credit per lookup (numbers outside the covered numbering plan areas are free)
Phone Spam Check	Returns the count of public consumer complaints filed against a number, a hint for agents handling an unknown caller. It is a count of reports, not a ruling.	1 credit per number with complaints on record

Connect it in four steps

Open a LookValid account, then generate a key under the API keys section of your dashboard.
When you configure the custom action, put the key in the connection or authorization settings of the action as a bearer credential, so Studio flows that execute the action never carry it in the flow itself.
In the flow, run the action with the caller or customer number; branch on found:false to a fallback route, and let an error answer end the step instead of guessing.
Map the returned values into variables of the flow, such as phone_type and phone_international, and use them in the routing and callback steps that follow.

A custom action that a Talkdesk Studio flow runs through its Execute Action component, set up to call the LookValid phone endpoint. The call is POST https://YOUR_API_HOST/v1/phone and costs 1 credit per valid number.

HTTP request step

1POST https://YOUR_API_HOST/v1/phone
2Authorization: Bearer {{LOOKVALID_API_KEY}}
3Content-Type: application/json
4
5{
6  "phone": "{{value}}"
7}

Where to read each value in the LookValid response
Response field	Goes into
data.valid	phone_is_valid
data.international_format	phone_international
data.number_type	phone_type

The recipe returns nothing when the lookup finds nothing, which costs no credits for this product, and stops with the error code and fix on a failed request.

Without code

Talkdesk is already built around calling outside systems from a flow, so the no-code route is the action itself: define an HTTP call to the phone endpoint with the bearer header and a JSON body, then run it from Studio. If instead you move customer numbers through an automation platform, a generic HTTP request step does the same job, with no dedicated app, between the trigger that carries the number and the step that updates the record.

REST and MCPOne shared credit balance

Questions

What does a Talkdesk lookup cost in credits?

It is billed as a normal phone lookup. The current amount is on the pricing page.

Does the check tell me who currently serves the number?

The phone check does not. The carrier lookup for US numbers shows the carrier a number block was first assigned to, which may differ if the number was moved since.

Where should the key be kept so agents never see it?

In the authorization settings of the custom action, not in a flow variable or a script, so it stays out of what an agent or a flow editor sees.

Sources

Talkdesk documentation: Executing an Action https://docs.talkdesk.com/docs/executing-an-action.md, read 2026-10-18
Talkdesk documentation index (llms.txt) https://docs.talkdesk.com/llms.txt, read 2026-10-18
LookValid API reference: Phone Numbering-Plan Validation https://lookvalid.com/docs/api/phone, read 2026-10-18

LookValid is run by Meralume Labs. It is not connected to, endorsed by or a partner of any company or product named on this page, and every product name belongs to its owner.

LookValid bills every lookup in credits from one shared balance, so the same key works for each check above.

See Phone Numbering-Plan Validation