Message deliverability overview

Many of our products leverage messaging channels like email, SMS, and WhatsApp. Successful delivery of messages sent by Stytch is critical, and we persistently monitor deliverability metrics in order to ensure a best-in-class user experience.

This resource will discuss how we optimize for deliverability across different channels, what to expect when using each channel, and common troubleshooting steps for deliverability issues.

At Stytch, we think of deliverability as the percentage of attempted messages or emails that are successfully delivered to the user's email server or cell carrier network.

We calculate deliverability by leveraging status webhooks from our messaging providers. We also track latency from the time a message or email is sent to when it is delivered to ensure that we're always using the highest-performing provider at any point in time.

We take several measures across all messaging channels to optimize for deliverability:

  • Fallback messaging providers: For each channel (SMS, WhatsApp, and email), we have a primary and secondary messaging provider. If deliverability drops below a certain threshold for a given provider, we automatically fall back to the secondary provider to ensure consistent deliverability.
  • Robust alerting and monitoring: To support automated failovers, we have robust monitoring in place for each distinct messaging provider and channel pair to ensure granular visibility into deliverability success. Status metrics differ in format amongst our different providers, but we've standardized our reporting into one cohesive channel.
  • Optimized templates and sender domains for SMS and email: We've tailored our SMS and email templates for each of our products to ensure optimal deliverability. Our default sender emails ( and and SMS/ WhatsApp numbers send large volumes of healthy messages and have accumulated a positive domain reputation over time.