# Sendblue, free: Phone validation API

> Detect iMessage availability before sending. Route iPhone users to iMessage and Android users to SMS or RCS — all from a single API call.

Sendblue's Free Sandbox plan for the phone validation API costs $0.00 per 1,000 phones. We check each provider's docs for 9 fields. Sendblue's docs list 1: Number.
Sendblue limits how many calls you get but gives no number.
We haven't run Sendblue through [our phone validation API benchmark](https://datacircle.dev/best-phone-validation-api.txt) yet.
This plan is free. We rank 1,342 plans for phone validation APIs by price. Half the plans cost $3.867 or less per 1,000 phones. [See the best free phone validation API plan.](https://datacircle.dev/best-phone-validation-api.txt)
[GuGuData's CNY 124 (about $19) monthly plan](https://datacircle.dev/validate-phone-apis/gugudata/cny-124-monthly/llms.txt) is the cheapest paid plan per 1,000 phones. GuGuData's CNY 124 (about $19) monthly plan charges nothing per call. You get as many phones as GuGuData's rate limit allows. [Keyronne's pay-as-you-go plan](https://datacircle.dev/validate-phone-apis/keyronne/pay-as-you-go/llms.txt) costs the least for 10,000 phones a month: $0.20.
[Trestle](https://datacircle.dev/validate-phone-apis/trestle/top-up-from-10-self-serve-pay-as-you-go-get-3-0-phone-intel-phone-validation-api/llms.txt), [Signal House](https://datacircle.dev/validate-phone-apis/signal-house/top-up-from-10/llms.txt) and [Data247](https://datacircle.dev/validate-phone-apis/data247/12-pack-membership-get-v3-0-verify247-phone/llms.txt) are the best phone validation API providers in the Datacircle benchmark.

- This page: https://datacircle.dev/validate-phone-apis/sendblue/free
- [Phone validation API in 2026: the best of 60+ compared](https://datacircle.dev/best-phone-validation-api.txt)
- Get it: https://www.sendblue.com/pricing?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=phone-validation-api-pricing
- Request: `GET https://api.sendblue.com/api/evaluate-service`
- API key: with the plan, on https://www.sendblue.com/pricing?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=phone-validation-api-pricing
- Its API docs: https://docs.sendblue.com/api/resources/lookups/methods/lookup_number?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=phone-validation-api-pricing
- Sold by: Sendblue (https://www.sendblue.com?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=phone-validation-api-pricing)
- Checked: 2026-11-09

## In the answer

- Completeness: 11%
- Number: ✓

## Price

- $ per 1,000 phones: $0.00
- Per: call
- Billing: free

## Aggregators

- Aggregators: none

## Charges

- Also pays for: 53 other Sendblue calls

## Not found

- $ per 1,000: $0.00

## In their words

- Their pitch: Detect iMessage availability before sending. Route iPhone users to iMessage and Android users to SMS or RCS — all from a single API call.

## Data

- What it checks: messaging apps
- Keep data: no limit
- Use data: Subject to your adherence to the terms set forth herein, Sendblue grants you the rights to use and employ the outputs generated from Sendblue services ("Outputs") in your operations. These Outputs may be influenced by proprietary algorithms and, as such, could be subject to certain third-party rights.

## Plan

- Pay: $0

## Rate limit

- Batch: 1

## Speed

- Answer: in the call

## The call

- You send: number
- Method: GET
- Path: /api/evaluate-service

## About the plan

- Plan: Free Sandbox
- Who can get it: anyone

## The 2 fields the plan's answer can hold

normalized number, iMessage support

## Sendblue's plans (3)

- [Sendblue, free](https://datacircle.dev/validate-phone-apis/sendblue/free/llms.txt): $0.00 per 1,000, 11% complete
- [Sendblue, $100 monthly](https://datacircle.dev/validate-phone-apis/sendblue/100-monthly/llms.txt): $33.333 per 1,000, 11% complete
- [Sendblue, contact us](https://datacircle.dev/validate-phone-apis/sendblue/contact-us/llms.txt): 11% complete

## Sendblue's calls (1)

- `GET /api/evaluate-service`: [Sendblue, free](https://datacircle.dev/validate-phone-apis/sendblue/free/llms.txt)

## Sendblue's APIs (1)

- [Sendblue: phone validation API pricing, 3 plans](https://datacircle.dev/validate-phone-apis/sendblue/free/llms.txt)

## Sendblue: phone validation API alternatives

- [Data Soap, £4.99 pack](https://datacircle.dev/validate-phone-apis/data-soap/4-99-pack/llms.txt): $33.271 per 1,000, 56% complete, live
- [Listar, top-up from €100,000, Diamond, POST /search/verify-phone-ownership](https://datacircle.dev/validate-phone-apis/listar/top-up-from-100000-diamond-post-search-verify-phone-ownership/llms.txt): $33.759 per 1,000, 67% complete, live
- [Endereco, pay as you go, Pro: 10,000-50,000 API requests a month](https://datacircle.dev/validate-phone-apis/endereco/pay-as-you-go-pro-10000-50000-api-requests-a-month/llms.txt): $33.759 per 1,000, 56% complete, live
- [LOX24, top-up, Direct](https://datacircle.dev/validate-phone-apis/lox24/top-up-direct/llms.txt): $33.759 per 1,000, 33% complete

## Sources

From each provider's own pricing page and docs, and from what providers tell us. We read this row from these pages on 2026-11-09.

- https://docs.sendblue.com/api?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=phone-validation-api-pricing
- https://docs.sendblue.com/api/resources/lookups/methods/lookup_number?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=phone-validation-api-pricing
- https://docs.sendblue.com/guides/check-imessage-support?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=phone-validation-api-pricing
- https://docs.sendblue.com/limits?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=phone-validation-api-pricing
- https://www.sendblue.com/features/number-lookup?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=phone-validation-api-pricing
- https://www.sendblue.com/pricing?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=phone-validation-api-pricing
- https://www.sendblue.com/terms-of-service?utm_source=datacircle.dev&utm_medium=referral&utm_campaign=phone-validation-api-pricing