If you’ve ever tried to add OTP login to a WooCommerce or Shopify store, you already know the problem isn’t finding an OTP service. It’s finding one that doesn’t turn into a two-week integration project. There are dozens of OTP and passwordless authentication tools out there, and most comparison articles about them read like they were copied from each vendor’s own marketing page. This one won’t. We looked at three specific platforms people keep asking us about, Authyo, OTPLESS, and otp.com, and pulled the actual numbers and features straight from their pricing and product pages rather than guessing.

Quick disclosure before we go further: we built Authyo. That doesn’t mean the other two aren’t worth using; it means we’re going to be upfront about where they’re a better fit than we are, and specific about where we aren’t.

The short answer

If you run a store on WooCommerce, Shopify, or Magento and want passwordless login plus order notifications without writing backend code, Authyo is built for exactly that. If you’re a developer who wants a bare-bones OTP API with published per-message pricing and nothing else, otp.com is the leanest option on this list. And if you’re building a fraud-sensitive product, like a fintech app, and you’re fine going through a sales conversation instead of a signup form, OTPLESS‘s device-and-behavior based approach is worth a look.

Here’s the detail behind that.

Authyo vs OTPLESS vs otp.com at a glance

	Authyo	OTPLESS	otp.com
Store plugins	Shopify, WooCommerce, Magento, Flutter	None — SDK only	None — API/SDK only
Login methods	OTP (SMS/Email/WhatsApp/Voice), magic link, passkeys, social login	Phone/email OTP, social login, device & behavior signals	OTP only (SMS, WhatsApp, Telegram, Email)
Fallback if a code fails	Yes, across channels	Not applicable — leans on risk signals instead of retries	Yes, automatic, billed per attempt
Pricing shown publicly	Yes — pay-as-you-go with volume discounts	No — sales quote only	Yes — exact per-country, per-channel rate card
Free to start	Yes, no card required ($1 credit given)	No free tier	Yes, $3 credit, no card required
Setup effort	Plugin install or shortcode — little to no code	SDK integration — needs a developer	REST API/SDK — needs a developer

Sources: Authyo pricing page, otp.com pricing page. OTPLESS does not have any live webpage

What you actually have to build to get each one working

This is the part most comparison posts skip, and it’s the part that matters most if you’re the one doing the integration.

Authyo ships as a plugin for Shopify, WooCommerce, and Magento, plus a package for Flutter apps. On WordPress, you can drop in a shortcode like “authyo_login” and get a working OTP login form without touching PHP. That’s the whole pitch: someone running a store who isn’t a developer can wire this up in an afternoon. It also supports magic links, passkeys, and social login (Google, Facebook, Microsoft, GitHub) if you want to go beyond OTP entirely.

otp.com gives you a REST API and official SDKs for Node.js, Python, Go, and PHP, plus an MCP server if you’re wiring this into an AI agent workflow. There’s no plugin for WooCommerce or Shopify. You send a phone number or email to /otp/send, it returns an ID, and you call /otp/verify with the code the user typed. It’s about as simple as an OTP API gets, but you’re building the login UI and the store integration yourself.

OTPLESS also ships SDKs rather than store plugins, and its main selling point isn’t the integration speed, it’s what happens after integration: it scores login attempts using device fingerprinting and behavioral signals so returning users often don’t see a code at all. That’s a genuinely different model from Authyo and otp.com, which are both fundamentally “send a code, check a code” systems.

Pricing: what you’ll actually pay

This is where things get concrete, because two of the three publish real numbers.

otp.com charges per verification sent, not per attempt to check a code. As of this writing, SMS to a US number costs $0.0132 per verification, while WhatsApp and Email are a flat $0.0012 worldwide and Telegram is $0.0120 worldwide, regardless of country. Checking the code a user typed is free no matter how many tries it takes. If your fallback chain needs to retry on a second channel because the first one didn’t land, that resend is billed as its own verification. New accounts start with $3 in free credit and no credit card is required. It’s transparent enough that you can model your exact monthly cost before you sign up.

Authyo runs on a pay-as-you-go model with volume discounts that kick in as usage grows, and a committed-use discount tier available if you talk to sales. You can start free with no credit card. The pricing calculator on the site is interactive and varies by country and plan, so rather than quote a number that might be stale by the time you read this, we’d point you to the live pricing page to plug in your own volume and country.

OTPLESS doesn’t publish pricing anywhere on its site. You’ll need to book a call or fill out a contact form to get a number. That’s not unusual for enterprise-leaning security tooling, but it does mean you can’t compare it on cost until you’re already a few steps into their sales funnel.

Which one should you actually pick

• Running an online store (WooCommerce, Shopify, Magento) and want OTP login plus order notifications without hiring a developer: go with Authyo. The plugin does the heavy lifting.
• Building a custom app or backend and want the cheapest, most transparent per-message OTP cost with full control over the login UI: otp.com fits. Just budget for the engineering time to build the UI around it.
• Building something in fintech or another fraud-sensitive space, with engineering resources and no urgency to see pricing upfront: OTPLESS’s device-and-behavior model is worth evaluating, even without a public rate card.

Frequently asked questions

Which OTP service works with WooCommerce out of the box?

Authyo is the only one of these three with a dedicated WooCommerce plugin. OTPLESS and otp.com are both SDK/API-first, so you’d need a developer to wire OTP login into a WooCommerce checkout yourself.

Is there a free OTP verification API?

Both Authyo and otp.com let you start for free without a credit card. otp.com gives new accounts $3 in credit to test with; Authyo’s free tier is available directly from its pricing page. OTPLESS does not offer a free plan.

How much does OTP verification cost per message?

It depends on the channel and country. On otp.com, US SMS is $0.0132 per verification, while WhatsApp and Email are a flat $0.0012 worldwide. Authyo uses a pay-as-you-go rate with volume discounts rather than a single flat number, so check its live pricing calculator for your country and plan. OTPLESS doesn’t publish per-message pricing.

Does otp.com support WhatsApp OTP with automatic fallback?

Yes. otp.com routes across SMS, WhatsApp, Telegram, and Email, and will automatically try the next channel in your routing order if the first one fails to deliver. Each attempt is billed as its own verification.

What’s the cheapest OTP API for developers?

On pure per-message cost, otp.com is the most transparent option to compare, since its rates are published for all 199 countries it supports. Whether it’s actually the cheapest for your use case depends on your channel mix and volume; Authyo’s volume discounts can make it more cost-effective at scale for a store already using its plugin ecosystem.

Ready to try Authyo on your store? Get started free, no credit card required.

Authyo WordPress Plugins : https://wordpress.org/plugins/search/authyo/
Authyo Shopify : https://apps.shopify.com/authyo

Note: Pricing and features referenced above reflect each provider’s public pages as of the time of writing and can change without notice. Always confirm current details directly on the vendor’s site before making a decision.