# SignalWire, top-up from $5, Prepaid balance, GET /api/relay/rest/lookup/phone_number/{e164_number}, Look up phone number, full: Phone validation API

> Returns validity and formatting information for any supplied E.164 phone number, with optional carrier and caller-name data.

SignalWire's phone validation API on its Prepaid balance plan. It costs $13.00 per 1,000 phones. It returns 6 of the 9 key fields we check: Number, Formats, Validity, Type, Carrier, Place.
Half of the 235 plans we rank by price cost $5.401 per 1,000 or less. This plan costs less than 18% of the 235 plans.
The cheapest plan we rank by price is [Twilio, top-up](https://datacircle.dev/validate-phone-apis/twilio/top-up/llms.txt), at $0.00 per 1,000.

- This page: https://datacircle.dev/validate-phone-apis/signalwire/top-up-from-5-prepaid-balance-get-api-relay-rest-lookup-phone-number-e164-number-look-up-phone-number-full
- [Best phone validation API in 2026](https://datacircle.dev/best-phone-validation-api.txt)
- Get it: https://signalwire.com/pricing/rates
- Its API docs: https://signalwire.com/docs/apis/rest/phone-number-lookup/lookup-phone-number
- Sold by: SignalWire (https://signalwire.com)
- Checked: 2026-10-25

## In the answer

- Completeness: 67%
- Number: ✓
- Formats: ✓
- Validity: ✓
- Type: ✓
- Carrier: ✓
- Place: ✓

## Price

- $ per 1,000: $13.00
- Billing: pay first

## Aggregators

- Aggregators: none

## Charges

- Per: call

## In their words

- Their pitch: Returns validity and formatting information for any supplied E.164 phone number, with optional carrier and caller-name data.

## Data

- Freshness: live
- Keep data: no limit
- Use data: "Customer retains ownership of all right, title, and interest in and to the Customer Content", which means content "generated by Customer via use of the SignalWire Services" (Cloud Agreement 4.D), "Customer may not engage in the illegal, harmful, or inappropriate use of the SignalWire Services" (6.B)

## Plan

- Pay: $5
- You get: $5
- Enough for: about 384 calls

## Rate limit

- Batch: 1

## Speed

- Answer: in the call

## The call

- You send: e164_number, include "carrier,cnam"
- Method: GET
- Path: /api/relay/rest/lookup/phone_number/{e164_number}

## About the plan

- Plan: Prepaid balance
- Who can get it: anyone with a SignalWire space and a payment method, new accounts stay in Trial mode until at least $5 of credit is added

## The 19 fields the plan's answer can hold

country calling code, national number, possible number, valid number, national format, international format, E.164 format, location, country ISO2 code, time zones, number type, carrier OCN, carrier LATA, carrier city, carrier state, carrier jurisdiction, carrier LEC, line type, caller ID name

## SignalWire's plans (1)

- [SignalWire, top-up from $5, Prepaid balance, GET /api/relay/rest/lookup/phone_number/{e164_number}, Look up phone number, full](https://datacircle.dev/validate-phone-apis/signalwire/top-up-from-5-prepaid-balance-get-api-relay-rest-lookup-phone-number-e164-number-look-up-phone-number-full/llms.txt): $13.00 per 1,000, 67% complete, live

## SignalWire's calls (2)

- `GET /api/relay/rest/lookup/phone_number/{e164_number}`, Look up phone number: [SignalWire, top-up from $5, Prepaid balance, GET /api/relay/rest/lookup/phone_number/{e164_number}, Look up phone number](https://datacircle.dev/validate-phone-apis/signalwire/top-up-from-5-prepaid-balance-get-api-relay-rest-lookup-phone-number-e164-number-look-up-phone-number/llms.txt)
- `GET /api/relay/rest/lookup/phone_number/{e164_number}`, Look up phone number, full: [SignalWire, top-up from $5, Prepaid balance, GET /api/relay/rest/lookup/phone_number/{e164_number}, Look up phone number, full](https://datacircle.dev/validate-phone-apis/signalwire/top-up-from-5-prepaid-balance-get-api-relay-rest-lookup-phone-number-e164-number-look-up-phone-number-full/llms.txt)

## SignalWire's APIs (1)

- [SignalWire: phone validation API pricing, 1 plan, {e164_number}, Look up phone number, full](https://datacircle.dev/validate-phone-apis/signalwire/top-up-from-5-prepaid-balance-get-api-relay-rest-lookup-phone-number-e164-number-look-up-phone-number-full/llms.txt)

## SignalWire: phone validation API alternatives

- [seven.io, top-up, Prepaid balance, GET /api/lookup/hlr](https://datacircle.dev/validate-phone-apis/seven-io/top-up-prepaid-balance-get-api-lookup-hlr/llms.txt): $11.253 per 1,000, 78% complete, live
- [VerificarEmails, €10 pack, MNP: 1,000 Phones, GET /phonemnp/validate/single](https://datacircle.dev/validate-phone-apis/verificaremails/10-pack-mnp-1000-phones-get-phonemnp-validate-single/llms.txt): $11.253 per 1,000, 67% complete, live
- [HLR Lookups, top-up, 1 - 1M, POST /hlr-lookup](https://datacircle.dev/validate-phone-apis/hlr-lookups/top-up-1-1m-post-hlr-lookup/llms.txt): $11.253 per 1,000, 56% complete, live
- [1Lookup, $7,990 yearly, Professional (annual), POST /hlr-lookup](https://datacircle.dev/validate-phone-apis/1lookup/7990-yearly-professional-annual-post-hlr-lookup/llms.txt): $13.317 per 1,000, 67% complete, live

## Sources

From each provider's own pricing page and docs, and from what providers tell us. We read this row from these pages on 2026-10-25.

- https://info.signalwire.com/hubfs/PDFs/SignalWire-Cloud-Agreement.pdf
- https://signalwire.com/docs/apis/rest/phone-number-lookup/lookup-phone-number
- https://signalwire.com/docs/apis/rest/space/balance/create-top-up
- https://signalwire.com/docs/platform/auto-top-up
- https://signalwire.com/docs/platform/rate-limits
- https://signalwire.com/docs/platform/trial-mode
- https://signalwire.com/legal
- https://signalwire.com/pricing/rates