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Get verified in a flash

Meet Flash Call Verification: the faster, more cost efficient alternative to traditional SMS verification. Multi-factor authentication has never been so smooth!

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The power of Flash Call Verification

The best option for you and your customers

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    Reduced friction

    With Sinch Flash Call, numbers can be verified using Android flash call verification, without any user interaction at all or a web application verification with minimal user interaction.
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    Speed is of the essence! If you’re looking to verify customers quickly, our Flash Call Verification is ready for the job. Flash Call is by far the fastest verification method.
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    Lower costs

    Yes, you can get premium service while saving money. With Flash Call Verification (using SMS as a fallback), you can save up to 70% on OTP costs compared to traditional SMS.
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Boost conversions and build a better UX

Don’t lose customers at the first hurdle. Build verification solutions to match expectations – quick and easy all the way. Multi-factor authentication has never been so smooth! 

Competitive and transparent pricing

With our direct local operator connections and intelligent routing we ensure your Flash calls always get through.

Get started

Get started in no time with our easy integration

Integrate using our REST API or SDK for iOS, Android and JavaScript through this two easy steps:

  1. Request verification Flash-call, see sample curl command on the right
  2. Report verification Flash-call
curl -X POST \
-H "Content-Type: application/json" --data " \
{ \
"identity": { \
"type":"number", \
"endpoint":"+1555123123" \
}, \
"method":"flashcall" \
}" \

Use cases

Verify users. Fight fraud. Build trust.


Ensure the highest level of security

Truecaller, the mobile app that's transforming the phonebook, has over 100 million customers around the world. With 2-Factor Authentication (2FA)key to the business, they turned to Sinch for Flash Call technology to verify user numbers.

badoo logo

Global reach

Popular app Badoo makes it fun to connect with new people locally to chat, date, meet up, or make new friends. Operating in 180 countries, Badoo needed a global verification solution - which they found in Sinch.

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A superior customer experience

Glide is the all-in-one app for live streaming video, text, and chat. Glide wanted to offer friction-free number verification to its growing global user base - and Sinch Flash Call verification proved a perfect match. "Ever since we integrated Sinch's Flash Call verification, we've seen a record increase in successful verifications across the globe," says Ari Roisman, Co-Founder and CEO at Glide.


One solution - all your verification needs

Easy integration

Using the lightweight Sinch Flash Call Verification SDK or our REST API, you can integrate Flash Call Verification into Android and web apps with just a few lines of code, & get verified in double quick time.

Route optimization

We continously optimize for the best routes, using the real time feedback from our Reporting API, leading to the highest possible conversion rates.

Top-notch security

Thanks to our pool of 100,000 numbers, which we draw on to make authentication calls, this is equivalent to a 5 digit SMS OTP code. Plus if needed, we can add higher security!

Seamless user experience

Our Android SDK will manage the complete call verification action on the device, guaranteeing a great use experience.

Automatic OTP interception

With Flash Call verification, the one-time password (OTP) is intercepted automatically - making the customer experience seamless from the first touchpoint!

Committed to data protection

Strong privacy, data protection and security are at the heart of our mission - so of course we do our best to make sure we're compliant with GDPR and other privacy policies.

Our transparent and competitive pricing to meet your business needs

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    Quick & easy sign-up
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    Free test credit
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    Easy to implement APIs & SDKs

Other questions about pricing? Talk to a pricing expert.


Frequently asked questions

Need more help?

Check out our extended FAQ here.

Talk to our experts

Contact our expert team to discuss our products and solutions

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    Reduced friction
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    Lower costs
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Enhance business and account security with Sinch Flash Call Verification

Start validating users phone numbers quickly and efficiently with easy and reliable integration through Sinch SDK or REST API. We are also available to discuss your business needs and find the right solution for you.