SMS Verification API
for growing companies

Verify your users anywhere in the world with the best prices, top deliverability, and zero spam with Prelude, the SMS API empowering your growth.

sms verification

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Trusted by leading companies

Reduce costs by 75%

Less attempts by authentication, the best price for each countries and no mark-up on SMS prices: Prelude helps you save user verification costs.

Reach a 95% conversion rate

Boost your verification  conversions worldwide with unmatched deliverability and no downtime, with our multi-routing and instant-fallback API.

Block 99% of spam

40% of your user authentication budget is wasted on spam and fraud. Our API prevent fraud before it impacts your bill, so you can send SMS to real users only.

SMS Deliverability

Achieve unstoppable global delivery rates

Prelude ensures global reach by connecting you to 30+ providers and 4 channels, optimizing routes for the best performance at the lowest cost.

With instant fallback to the next best route, enjoy 99.99% deliverability and a 95% conversion rate across four channels—no downtime, ever.

Anti Fraud

Stop SMS pumping from draining your budget

Connect only with real users, even in countries with a high incidence of fraudulent traffic.

With four layers of protection, Prelude prevents fraud with the utmost precision, blocking 99% of spam and saving our users thousands of euros.

Analytics

Connect with trustworthy phone numbers only

Check the risk-scoring of any number with our Look-Up API.

Prelude goes beyond than your standard SMS OTP Service

Features Large

Instant implementation

Implement SMS OTP into your app in less than a sprint using Prelude API. It works with any technical setup and programming language.

No more registration pain

Prelude is registered worldwide with all providers so you can start sending OTP right away. Our pre-approved templates are optimized for conversions.

Dedicated customer support

Access our premium support at no additional charge through dedicated support channels on Slack, email, or phone. We make your issues ours.

Optimized routing

Our multi-route SMS OTP Service saves you money by selecting the most efficient carrier from major global providers to ensure user authentication.

Customization

Customize your Sender ID and OTP message to match your brand identity, build trust and brand recognition.

Scalability

Access over 1000 routes in 230 countries, allowing your company to expand globally without needing new providers or APIs.

A price that doesn’t punish your success

Prelude leverages real-time competition among providers to boost conversion rates at minimal cost. With no added margins on SMS prices, growing with Prelude is easy due to our lower prices and higher deliverability.

€0 mark-up on message price

€0 for fraud protection

€0 for customer support

Explore our pricing
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Frequently asked questions

What are the benefits of an SMS Verification API?

Used by 90% of consumers, SMS is the most popular 2FA. Sticking with this method ensures a high authentication rate.

SMS OTP prevents 99% of automated intrusions, making it one of the most secure means of authentication against phishing and spoofing. It also enhances data security and GDPR compliance.

Over 25% of online users abandon transactions due to security concerns. Don’t lose these customers. Show them their data and financial information is safe with your company.

How does our SMS Verification API work?
  1. Your user initiates a login or a transaction requiring OTP verification.
  2. Your application calls Prelude API to generate and send an OTP to the mobile number.
  3. Prelude API generates a unique OTP sent to the user’s registered mobile number via SMS.
  4. The user enters the OTP into your application.
  5. Prelude API validates the OTP if it matches the generated one within the valid time window.
How to get started with Prelude?
  1. Initialize the SDK: We provide SDKs in all the major programming languages to make your life easier and your users safer.

  1. Send and verify a code Receive a code by calling the Authentication endpoint with your phone number and return it to the Check endpoint.

  2. Add fraud signals Add signals such as your user’s IP address or App version to your Authentication requests to better prevent fraud and reduce your expenses

  3. Start verifying at scale! You’re all set! You can now access your dashboard and monitor the OTP sent.

Check our Quickstart Guide →

When should you use an user verification API?
  • Two factors authentication: Verify your user identify during account registration, login or password recovery.
  • Financial operations and online payment: Keep your user transactions safe by adding an extra layer of security.
  • Protecting access to high-value information: Protect your user sensitive informations by requiring a SMS OTP authentication.