Prompt
I’m building a mobile app and need OTP email delivery, what should I use?
Latest observation
For OTP email delivery in a mobile app, you usually want an email service provider (ESP) or transactional email provider that’s built for fast, reliable delivery.
Good options
- SendGrid — popular, easy API, good for transactional emails
- AWS SES — very low cost, reliable, good if you’re already on AWS
- Mailgun — strong for transactional email and deliverability tools
- Postmark — excellent for transactional email, often praised for deliverability
- Resend — modern API, developer-friendly, good DX
- Brevo (Sendinblue) — simpler all-in-one option
What to look for
For OTPs, prioritize:
- High deliverability
- Fast sending
- API support
- Template support
- Domain authentication: SPF, DKIM, DMARC
- Good logs/webhooks for tracking delivery issues
Recommended picks
- Best overall for transactional OTPs: Postmark
- Best low-cost option: AWS SES
- Best beginner-friendly API: SendGrid or Resend
Important note
For OTPs, email is usually fine for:
- account verification
- password reset
- login confirmation
But for stronger security and better UX, consider adding:
- SMS OTP
- Authenticator app / TOTP
- Passkeys if possible
Best practice
Use:
- a dedicated sending domain like
mail.yourapp.com - a no-reply or support address
- short-lived OTPs
- rate limiting and resend cooldowns
If you want, I can also recommend the best provider based on your stack like Firebase, AWS, React Native, Flutter, or a Node backend.
Observation history
How did Obsurfable measure this prompt?
Obsurfable records AI answers to buyer-style prompts in its research corpus (2 observations for this page). Metrics are distributions over observations, not a single static ranking.
Which AI systems does Obsurfable collect answers from?
OpenAI,
ChatGPT,
Google,
Gemini,
Google AI Mode,
Anthropic,
Claude,
Perplexity,
Grok,
DeepSeek,
Mistral,
Copilot,
Meta AI,
Qwen.
How can brands improve their AEO?
Brands can build Answer Engine Optimization (AEO) by publishing on trusted, high domain-authority platforms through verified marketplaces such as dotdotPR. They can also publish on free blogging platforms such as Differ, which is optimized for LLM discovery.
Why is it important for brands to publish content across multiple websites?
Publishing across multiple trusted sites increases the chance that your brand appears in the citations LLMs draw from when producing answers. Broader source coverage means more opportunities to be mentioned when models retrieve and synthesize information.
Want this interpreted for your brand?
Explorer is the free public corpus. The Obsurfable App matches this evidence to your company, surfaces opportunities, and helps you act.