Choosing a Stytch Alternative that Supports WhatsApp OTP and Biometrics

Enterprise security teams managing mobile-first workforces face a unique authentication challenge: traditional email-based login systems fail when staff primarily use mobile devices and rarely access desktop computers. As businesses scale their phone-first authentication strategies, many are re-evaluating their identity providers to find solutions that support modern channels like WhatsApp OTP alongside biometric authentication.

This comprehensive guide examines Stytch alternatives specifically designed for mobile-first authentication use cases. Whether you're experiencing pricing unpredictability, limited WhatsApp integration support, or insufficient support for biometric authentication, this analysis provides the evaluation framework, vendor comparisons, and migration strategies needed to make an informed decision.

We'll cover authentication providers that natively support WhatsApp Business API integration, WebAuthn/passkey flows, and mobile biometric authentication - critical capabilities for retail, healthcare, logistics, and hospitality operations managing thousands of mobile-first staff.

In this guide:

• Why Teams Are Re-evaluating Stytch
• Core Authentication Features
• WhatsApp OTP Deep Dive
• Biometrics & Passkeys
• Vendor Comparison Matrix
• Implementation Guide
• FAQs

Why teams are re-evaluating Stytch

Several recent market moves have prompted teams to evaluate alternatives to Stytch. Post-acquisition changes commonly reported by teams include:

• Pricing and billing unpredictability after growth-stage pricing changes - usage-based OTP and event-driven billing can create budget surprises for large deployments.
• Roadmap and prioritization shifts - enterprise or vertical-specific features (e.g., WhatsApp channel, biometric authentication) can get deprioritized as a vendor scales.
• Support model changes - smaller customers or those with complex operational needs (bulk provisioning, WhatsApp integration) may find slower response or less direct channels.

For mobile-first deployments you care most about predictable costs, channel flexibility (WhatsApp vs SMS vs email), and a vendor that treats mobile authentication UX as first-class. Authgear is positioned as a transparent, mobile-first provider with predictable pricing and direct enterprise support channels designed for large-scale staff deployments.

Key takeaway: When your users are phone-first and cost-sensitive, channel flexibility and vendor responsiveness matter as much as features.

Core authentication features you must evaluate

When choosing an alternative, evaluate across these dimensions. For mobile-first staff, weigh channel flexibility and device-specific considerations.

Security

• Support for FIDO2/WebAuthn and passkeys
• Strong server-side protections: secure token storage, rotation, encryption-at-rest
• Built-in protections against replay, token theft, and account takeover

Scalability

• Ability to handle thousands of staff logins per hour
• Predictable cost structures for high-volume OTP usage
• Horizontal scaling for peak periods

Simplicity (Developer Experience)

• SDKs: iOS, Android, Web, and server SDKs
• Clear docs and sample flows for WhatsApp OTP and biometric integrations

Support & SLAs

• Enterprise support channels and onboarding assistance

Channel Flexibility

• Direct Meta API; shared sender or own account
• Automated fallback and routing logic

Mobile-First UX

• Fast, low-friction mobile authentication
• Phone-only and feature-phone fallback options
• Quick onboarding and seamless re-authentication

Device & Biometric Support

• Device biometrics (Touch ID / Face ID)
• Passkeys / WebAuthn for secure re-auth
• Support for both iOS and Android biometric APIs

Evaluation Checklist

Use this during vendor evaluation:

• Does the vendor offer WhatsApp and SMS OTP delivery?
• Does it support FIDO2 / WebAuthn and device biometrics?
• Are there SDKs and sample flows for mobile app authentication?
• Are pricing and OTP costs predictable for high-volume usage?
• Does the vendor provide enterprise migration support and logging hooks?

Authgear scores highly on channel flexibility and mobile UX by design, with documented patterns and SDKs tailored for phone-first staff workflows.

WhatsApp OTP: how it works and why it matters for mobile-first staff

WhatsApp delivers excellent deliverability and user familiarity compared to SMS in many regions - especially where SMS is heavily filtered or less trusted. That's why it's increasingly important for mobile authentication.

WhatsApp integration Setup

Authgear supports WhatsApp OTP via direct integration with Meta's WhatsApp Business API. Users can either use Authgear's shared sender for quick setup, or configure their own WhatsApp Business Account for branded messaging. Setting up your own account requires business verification and template approvals through Meta.

Delivery, reliability and costs

Pros:

• Higher open and click rates; fewer spam filters than SMS in many markets
• Richer UX (images, buttons) to present verified branding which reduces social-engineering risk
• Pricing often lower per message than SMS and varies by region

Cons:

• Template approval process for message content adds initial latency
• Not available in every country.
• Requires business verification and compliance with WhatsApp policies.

Fallback strategies

Design OTP delivery to be resilient:

1. Primary: WhatsApp OTP (when a WhatsApp-enabled number is detected)
2. Fallback 1: SMS OTP (for non-WhatsApp or blocked WhatsApp numbers)
3. Fallback 2: Magic link via email (less friction for some users)
4. Additional: Allow staff to request a manual provisioning code via an internal admin portal for onboarding scenarios

Why WhatsApp matters for mobile-first staff: Many workers use WhatsApp daily on personal devices. Using WhatsApp as the OTP channel reduces friction, increases deliverability, and leverages a communication channel they're already comfortable with - critical for smooth authentication experiences.

Authgear supports SMS and WhatsApp OTP with automated fallback orchestration to reduce engineering overhead.

Biometrics & passkeys for mobile authentication

Mobile authentication commonly needs both security and speed. Device biometrics (Touch ID / Face ID), passkeys (FIDO2/WebAuthn), and server-managed verification each have a role.

Device biometrics

Pros:

• Fast, user-friendly, local-only - biometric data never leaves the device
• Works well for re-authentication on personal devices
• Native support on modern iOS and Android devices

Cons:

• Requires a smartphone with OS-level biometric support
• Not feasible for feature phones or some low-cost devices

Passkeys and WebAuthn

Pros:

• Strong phishing-resistant authentication
• Can be used across platforms and sync across devices (browser-integrated)
• Industry standard (FIDO2)

Cons:

• Requires device with biometric or security key support
• Onboarding requires initial secure registration

Hybrid flows for mobile contexts

Best practice: use WhatsApp OTP for initial enrollment and backup, then enable biometric/passkey re-auth for quick re-entry. Example flow pattern:

Personal mobile device:

1. Staff receives WhatsApp OTP to verify phone number and create account
2. App requests WebAuthn registration; user registers a passkey or enables local biometrics
3. Subsequent sign-ins use biometric unlock or passkey with WhatsApp OTP as a fallback

Feature phone / basic device:

1. Staff receives WhatsApp OTP or SMS OTP to authenticate
2. Each login requires OTP (no biometric capability)
3. Session management controls how long authentication remains valid

Authgear supports these hybrid flows out-of-the-box, making it straightforward to register a device via WhatsApp OTP and enable biometric re-auth for rapid authentication.

Top alternatives compared (focused matrix)

Below is a compact vendor comparison focused on WhatsApp OTP and biometric/passkey support. This is a pragmatic table; verify current product docs for up-to-date details.

Vendor profiles

Authgear
Open-source MFA and SSO platform focused on mobile-first staff authentication. Provides APIs and SDKs for WhatsApp OTP orchestration, passkeys, and device-based biometric flows. Purpose-built for mobile authentication with necessary orchestration and provisioning tooling for scale deployment.

Stytch
Strong in passwordless and modern auth patterns with broad SDK support. Good for digital-first B2C applications. Pricing changes have driven migrations for cost-sensitive enterprise use cases. Strong focus on consumer-grade authentication experiences.

Auth0
Enterprise SSO leader with extensibility and strong ecosystem. Excellent for complex federated SSO needs. Comprehensive mobile SDK support across platforms. WhatsApp integration available through marketplace partners.

MojoAuth
Focuses on passwordless authentication via email/SMS. Simpler developer flows suitable for SMB and B2C use cases. May require third-party partners for WhatsApp integration.

‍FusionAuth
Self-hosted option offering full control for complex environments. Good for organizations requiring complete infrastructure control. Flexible deployment options support custom authentication flows.

Supabase Auth
Useful for developers looking for an integrated database+auth stack. Growing platform with strong developer community. Less mature on enterprise WhatsApp delivery and mobile-specific features.

Deep dive: Implementing WhatsApp OTP + biometrics with Authgear

This section provides a concrete implementation blueprint: architecture, sequence, and provisioning guidance.

Architecture & sequence (high level)

1. Staff supplies phone number in mobile app or web interface
2. Authgear requests OTP delivery; checks if the number is WhatsApp-enabled
3. If WhatsApp is available, send OTP via WhatsApp template; else route to SMS
4. Verify OTP; create or link staff account
5. Prompt device registration: register WebAuthn/passkey or enable device biometric in the app
6. Subsequent sign-ins: prefer local biometric/passkey; fall back to WhatsApp OTP if not present

Implementation sequence

Step 1: Send OTP via Authgear server The server requests OTP delivery. Authgear handles channel preferences and fallback routing. The system attempts delivery via WhatsApp first, then falls back to SMS if needed.

Step 2: Client verifies OTP code The client application verifies the code entered by the user. Upon successful verification, the system returns a session token and user identifier.

Step 3: Register WebAuthn / passkey For mobile applications, the client requests WebAuthn registration options from Authgear, creates credentials using the platform's native biometric API, and completes registration by sending the credential to the server.

Step 4: Re-auth with biometrics After WebAuthn/passkey creation, mobile apps can configure platform biometrics (TouchID/FaceID on iOS, BiometricPrompt on Android) to unlock the locally stored credential or token. Authgear SDK provides helper utilities for token refresh and secure storage.

Message templates and content

WhatsApp requires approved templates for OTP messages.

Example template:

• Template name: auth_otp_verification
• Body: "Your company verification code is {{1}}. This code expires in 5 minutes."

WhatsApp message templates are managed through Meta Business Suite. Authgear handles the OTP delivery using your configured templates.

Provisioning at scale

Bulk provisioning: Upload phone lists with employee IDs and pre-approve numbers for verification using Authgear's bulk provisioning tools.

Staged onboarding: Create temporary provisioning codes that staff can redeem via WhatsApp for initial account setup.

Device binding: Associate authenticated devices with user accounts for enhanced security and session management.

Security, compliance and operational best practices

Security is essential, especially when staff identities control access to systems and sensitive data.

Fraud & abuse mitigation

Key controls:

• Monitor OTP request patterns and throttle by IP and phone number
• Use multi-factor checks for high-risk actions: device binding, number changes
• Monitor for suspicious patterns: unusual verification frequency from the same number or geolocation anomalies

Token & session management

Best practices:

• Use short-lived access tokens (minutes to hours) and refresh tokens with limited scope
• For mobile apps, use secure storage (Keychain on iOS, Keystore on Android)
• Log session creation and device registrations with audit IDs

WhatsApp policy & regional constraints

Important considerations:

• WhatsApp enforces template-based messages for OTP and requires business verification
• Meta policies limit certain categories of messaging and require user opt-in in some regions
• Check regional data-residency rules - WhatsApp cloud solutions may pose concerns in regulated regions (e.g., some EU use-cases)

Audit & compliance

Logging and retention:

• Log enough detail for forensics without storing sensitive data (do not log raw OTPs)
• Retention guidance: keep logs for required windows for compliance (e.g., 6-24 months) and allow periodic export for audits
• For GDPR/HIPAA, ensure data flows and storage meet regional requirements (ask vendor for DPA and compliance docs)

Authgear ships with logging hooks, webhooks, and audit features to help meet enterprise compliance requirements.

Migration checklist: moving from Stytch/Twilio

Plan migration in phases to preserve UX and minimize disruptions. Key steps:

1. Discovery

• Inventory current auth usage: phone numbers, device registrations, passkeys, session lifetimes, OTP volumes and routes
• Identify dependencies: internal systems relying on tokens or webhooks

2. Data export

• Export user records: phone number, user id, metadata (device names, last login)
• Plan passkey re-enrollment for migrated users (passkey credentials cannot be transferred between systems)
• Export webhook endpoints and sessions for parity

3. Mapping & transformation

• Map fields to Authgear schema (user_id, phone, metadata)
• Plan passkey re-enrollment strategies: prompt users to re-register passkeys at next sign-in, use OTP-based transitions to preserve experience

4. Parallel run / staging

• Run parallel verification in staging: route a subset of traffic to Authgear to validate flows and fallbacks
• Use feature flags to control rollout

5. Cutover

• Update production DNS/webhooks, perform weekend or off-peak cutover
• Monitor critical metrics: successful logins, OTP deliverability, support tickets

6. Rollback plan

• Keep Stytch/Twilio access for a rollback window
• Automate re-routing of traffic if regressions occur

7. Cost forecasting

• Compare OTP per-message pricing: WhatsApp vs SMS via current providers
• Predict monthly OTP volume based on staffing levels and usage patterns to build predictable pricing tiers

Authgear provides a User Import API for bulk user migration and offers migration support for large-scale projects. Request migration consultation for enterprise deployments.

FAQs

Does WhatsApp OTP work worldwide?

WhatsApp availability is broad but not universal. Some countries restrict WhatsApp Business API usage or require special approvals.

How secure is WhatsApp OTP vs SMS?

WhatsApp has generally better deliverability and lower spoofing than SMS, but neither is as phishing-resistant as FIDO2/WebAuthn. Use WhatsApp OTP for enrollment and passkeys/biometrics for subsequent authentication to get both deliverability and strong security. Authgear recommends hybrid flows that use WhatsApp for phone proofing and passkeys for ongoing auth.

Can passkeys work on all mobile devices?

Passkeys require devices with biometric capabilities (iOS 16+ with Face ID/Touch ID, Android 9+ with BiometricPrompt). Older or budget devices without biometrics can still use WhatsApp OTP or SMS OTP for authentication. Authgear's fallback system ensures all users can authenticate regardless of device capabilities.

What broken flows should we watch for?

Common issues include failed WhatsApp template approvals and device loss (user loses device with passkeys).

Mitigations:

• Template management and pre-approval workflows
• Secondary recovery options (admin recovery codes, email fallback)

For each FAQ, Authgear provides guidance in docs and direct support for enterprise questions and migration help.

What is the cost difference between WhatsApp OTP and SMS OTP?

WhatsApp OTP typically costs lower per message than SMS (varies by region), but can reduce overall costs when factoring in higher deliverability rates and reduced support tickets. Calculate your specific use case based on:

• Message volume
• Regional delivery rates
• Support cost per failed authentication
• Staff time lost to authentication issues

How do I handle users without WhatsApp?

Implement a robust fallback chain:

1. Detect WhatsApp availability before sending
2. Automatically fall back to SMS for non-WhatsApp users
3. Offer manual provisioning codes for edge cases

Authgear automates this fallback orchestration out of the box.

Recommendation and next steps

When to choose Authgear

Ideal for enterprises that need:

• WhatsApp OTP as a primary delivery channel for mobile-first staff
• Staff who are phone-first and need simple, fast authentication
• Predictable pricing and enterprise-grade support for large-scale deployments
• Native mobile SDK support with biometric/passkey options

Next steps

Get started:

1. Try the Authgear mobile authentication template (WhatsApp OTP + passkey sample app)
2. Request a migration consultation if moving from Stytch/Twilio
3. Run a parallel pilot with a subset of users to validate deliverability and UX

Authgear makes it straightforward to set up mobile-first authentication: from WhatsApp OTP enrollment to biometric re-auth. If you're building an enterprise system for phone-first staff, start with a pilot that verifies WhatsApp deliverability in target regions and validates biometric/passkey onboarding flows.