# State of AI Search: Email API - November 2026

> We asked ChatGPT, Claude, Gemini, Perplexity, and Google's AI Overview 20 questions about transactional email APIs and analyzed 818 answers. Resend leads with 79% visibility.

- **Published:** November 4, 2026
- **Assistants:** ChatGPT, Claude, Gemini, Perplexity, and Google's AI Overview
- **Coverage:** 20 prompts, 818 answers, 15 tracked brands, 397 cited domains
- **Data:** [data.csv](https://www.usenotra.com/state-of-ai-search/email-api/2026-11/data.csv?ntr=hiXEwbKyAVT7wcXC)

## Key findings

- Resend and Postmark are neck and neck: 79% and 79% on average across the assistants.
- Resend is also named first most often, in 34% of answers on average across the assistants.
- Claude names 5.5 tracked brands per answer, Perplexity only 2.7.
- The assistants agree on the brand to name first for 40% of prompts.
- Google showed an AI Overview for 90% of the prompts we checked.

## Visibility ranking

Visibility is the share of answers that name the brand. Named first is the share that name it before any other tracked brand, own site cited the share that link to the brand's own domain. All three are averaged across the assistants, so each assistant counts the same however many answers it gave.

| # | Brand | Visibility | Named first | ChatGPT | Claude | Gemini | Perplexity | AI Overview | Own site cited |
| ---: | --- | ---: | ---: | ---: | ---: | ---: | ---: | ---: | ---: |
| 1 | [Resend](https://resend.com) | **79%** | 34% | 96% | 98% | 82% | 50% | 72% | 16% |
| 2 | [Postmark](https://postmarkapp.com) | **79%** | 25% | 86% | 94% | 80% | 64% | 72% | 11% |
| 3 | [Amazon SES](https://aws.amazon.com) | **68%** | 12% | 71% | 93% | 69% | 48% | 61% | 7% |
| 4 | [SendGrid](https://sendgrid.com) | **63%** | 9% | 63% | 89% | 74% | 33% | 56% | 2% |
| 5 | [Mailgun](https://mailgun.com) | **49%** | 6% | 52% | 68% | 53% | 24% | 50% | 16% |
| 6 | [Brevo](https://brevo.com) | **26%** | 2% | 25% | 37% | 30% | 20% | 17% | 4% |
| 7 | [Mailtrap](https://mailtrap.io) | **20%** | 0% | 8% | 30% | 27% | 13% | 22% | 15% |
| 8 | [Loops](https://loops.so) | **8%** | 3% | 12% | 13% | 6% | 10% | 0% | 7% |
| 9 | [Customer.io](https://customer.io) | **8%** | 3% | 9% | 11% | 6% | 8% | 6% | 4% |
| 10 | [MailerSend](https://mailersend.com) | **7%** | 2% | 3% | 11% | 9% | 3% | 11% | 3% |
| 11 | [SparkPost](https://sparkpost.com) | **1%** | 0% | 1% | 3% | 1% | 0% | 0% | 0% |
| 12 | [Plunk](https://useplunk.com) | **1%** | 0% | 0% | 2% | 0% | 0% | 6% | 0% |
| 13 | [ZeptoMail](https://zeptomail.com) | **1%** | 0% | 0% | 3% | 0% | 0% | 0% | 0% |
| 14 | [Bird](https://bird.com) | **1%** | 0% | 0% | 1% | 1% | 2% | 0% | 2% |
| 15 | [Mailchimp Transactional](https://mailchimp.com) | **0%** | 0% | 1% | 1% | 0% | 0% | 0% | 0% |

## By assistant

| Assistant | Model | Answers | Brands per answer | Sources per answer |
| --- | --- | ---: | ---: | ---: |
| ChatGPT | ChatGPT app | 200 | 4.2 | 3.6 |
| Claude | `anthropic/claude-opus-5.5` | 200 | 5.5 | 6.1 |
| Gemini | Gemini app | 200 | 4.3 | 5.7 |
| Perplexity | `perplexity/sonar` | 200 | 2.7 | 10 |
| AI Overview | Google Search | 18 | 3.7 | 6.1 |

ChatGPT, Gemini and Google were read from the consumer apps in the US, so their underlying models are not reported. Claude and Perplexity were asked through their APIs with web search. Earlier editions asked every assistant through its API, so changes from those editions are not like-for-like.

## Prompts

The 20 questions we asked, with the brand named first most often and the others that came up.

| # | Prompt | Named first | Also named |
| ---: | --- | --- | --- |
| 1 | sendgrid alternatives with better deliverability | **SendGrid** | Postmark, Amazon SES, Mailgun, Mailtrap, +6 more |
| 2 | best email api for product and marketing emails in one place | **Brevo** | SendGrid, Loops, Resend, Customer.io, +6 more |
| 3 | how do i send transactional emails from several customer domains | **Amazon SES** | SendGrid, Postmark, Resend, Mailgun, +6 more |
| 4 | best smtp service for a django app | **Postmark** | Amazon SES, Brevo, Resend, Mailgun, +5 more |
| 5 | best transactional email api | **Resend** | Postmark, Amazon SES, SendGrid, Mailgun, +4 more |
| 6 | cheapest reliable email api for a startup | **Amazon SES** | Resend, Brevo, Postmark, Mailgun, +4 more |
| 7 | which email api has the best developer experience | **Resend** | Postmark, Amazon SES, SendGrid, Mailgun, +4 more |
| 8 | best email api with react email templates | **Resend** | Postmark, Amazon SES, SendGrid, Mailgun, +4 more |
| 9 | i need to send receipts and notifications from my app, what service | **Resend** | Postmark, SendGrid, Amazon SES, Mailgun, +4 more |
| 10 | best transactional email api with an eu data region | **Mailgun** | Brevo, SendGrid, Resend, Postmark, +4 more |
| 11 | what should i use to send emails from my next.js app | **Resend** | Postmark, Amazon SES, SendGrid, Mailtrap, +3 more |
| 12 | what email provider should i use for high volume transactional email | **Amazon SES** | SendGrid, Postmark, Mailgun, Resend, +3 more |
| 13 | which email api is best for deliverability to gmail | **Postmark** | Amazon SES, Resend, SendGrid, Mailgun, +3 more |
| 14 | which email api makes bounce and complaint handling easiest | **Postmark** | Resend, Amazon SES, Mailgun, SendGrid, +3 more |
| 15 | best email provider for a hobby project | **Resend** | Brevo, Postmark, Amazon SES, SendGrid, +3 more |
| 16 | best email service for saas onboarding emails | **Loops** | Customer.io, Resend, Postmark, Brevo, +2 more |
| 17 | what's the easiest way to send emails from a serverless function | **Resend** | Amazon SES, Postmark, SendGrid, Mailgun, +2 more |
| 18 | how do i send password reset emails from node | **SendGrid** | Resend, Amazon SES, Mailgun, Postmark, +1 more |
| 19 | i need reliable email webhooks and delivery logs, what should i use | **Postmark** | Resend, Amazon SES, SendGrid, Mailgun, +1 more |
| 20 | resend vs postmark vs sendgrid | **Resend** | Postmark, SendGrid, Amazon SES, Mailtrap |

## What the assistants say

### Resend

> Resend is the best overall choice for developer experience, ease of integration, and modern applications.
>
> ChatGPT, asked "best transactional email api"

> Resend: best for developers and the best free tier
>
> Claude, asked "cheapest reliable email api for a startup"

> Resend was built from the ground up to give developers the absolute best modern experience.
>
> Gemini, asked "resend vs postmark vs sendgrid"

### Postmark

> Postmark: Best when password resets, login codes, receipts and other critical emails must arrive reliably.
>
> ChatGPT, asked "best transactional email api"

> Postmark: It's widely seen as best for deliverability, at $15/month for 10K emails.
>
> Claude, asked "cheapest reliable email api for a startup"

> Postmark: Known for the absolute best transactional deliverability and speed.
>
> Gemini, asked "best email api with react email templates"

### Amazon SES

> Amazon SES: Best when you're sending hundreds of thousands or millions of emails and want to minimize costs.
>
> ChatGPT, asked "best transactional email api"

> SES default plan: Since July 2026, new SES accounts start on an "Essentials" plan at about $0.16 per 1K.
>
> Claude, asked "cheapest reliable email api for a startup"

> Amazon SES (Best for lowest cost on AWS): If your app is hosted on AWS, SES is dirt-cheap, but you have to build out a lot of the bounce/complaint tracking infrastructure yourself.
>
> Gemini, asked "i need to send receipts and notifications from my app, what service"

### SendGrid

> SendGrid wouldn't be my first choice unless you specifically need its broader marketing and enterprise feature set.
>
> ChatGPT, asked "resend vs postmark vs sendgrid"

> SendGrid or Mailgun: best for high volume with a fuller feature set
>
> Claude, asked "what email provider should i use for high volume transactional email"

> SendGrid / Amazon SES (Best for massive scale or legacy infrastructure)
>
> Gemini, asked "what should i use to send emails from my next.js app"

### Mailgun

> Mailgun - Best if you need more control and infrastructure features.
>
> ChatGPT, asked "sendgrid alternatives with better deliverability"

> Mailgun (EU region): the best all-round choice for most teams
>
> Claude, asked "best transactional email api with an eu data region"

> Mailgun: Best when inbound email routing or flexible sending infrastructure matters.[1][6]
>
> Perplexity, asked "best transactional email api"

## Cited sources

The domains the assistants link to most, by share of answers that cite them at least once, averaged across the assistants.

| # | Domain | Cited in | ChatGPT | Claude | Gemini | Perplexity | AI Overview | Top page |
| ---: | --- | ---: | ---: | ---: | ---: | ---: | ---: | --- |
| 1 | [sequenzy.com](https://sequenzy.com) | **21%** | 20% | 14% | 7% | 45% | 17% | [21 Best Email APIs for Developers in 2026 \| Sequenzy](https://www.sequenzy.com/blog/best-api-first-email-platforms) |
| 2 | [resend.com](https://resend.com) | **16%** | 14% | 35% | 3% | 5% | 22% | [Pricing - Resend](https://resend.com/pricing) |
| 3 | [mailtrap.io](https://mailtrap.io) | **15%** | 21% | 23% | 7% | 20% | 6% | [6 Best Transactional Email Services Compared \\[2026\\]](https://mailtrap.io/blog/transactional-email-services/) |
| 4 | [mailgun.com](https://mailgun.com) | **15%** | 4% | 4% | 8% | 20% | 39% | [Regions - Transactional Email API Service for Developers - Transactional Email API Service For Developers \| Mailgun](https://www.mailgun.com/about/regions/) |
| 5 | [twilio.com](https://twilio.com) | **15%** | 12% | 20% | 10% | 15% | 17% | [The 5 top email API services for developers in 2026 - Twilio](https://www.twilio.com/en-us/blog/insights/best-email-api) |
| 6 | [reddit.com](https://reddit.com) | **14%** | 0% | 4% | 0% | 5% | 61% | [r/django](https://www.reddit.com/r/django/comments/14s4bwg/what_should_i_use_for_sending_mail_in_django_i_am/) |
| 7 | [youtube.com](https://youtube.com) | **13%** | 0% | 0% | 0% | 5% | 61% | [Reset Password - Part 3: Send Password Reset Email  \| Part #162](https://www.youtube.com/watch?v=VsU6QxI_mhc) |
| 8 | [postmarkapp.com](https://postmarkapp.com) | **11%** | 15% | 17% | 6% | 0% | 17% | [Postmark Pricing and Free Trial](https://postmarkapp.com/pricing/) |
| 9 | [courier.com](https://courier.com) | **10%** | 8% | 6% | 4% | 27% | 6% | [Best Email API for Developers in 2026: A Technical Comparison](https://www.courier.com/blog/best-email-api-providers-for-developers) |
| 10 | [dreamlit.ai](https://dreamlit.ai) | **10%** | 20% | 20% | 4% | 0% | 6% | [Best Email API Providers in 2026: 8 APIs Compared](https://dreamlit.ai/blog/best-email-api-providers) |

## More reports

- [AI visibility](https://www.usenotra.com/state-of-ai-search/ai-visibility/2026-11?ntr=hiXEwbKyAVT7wcXC): Peec AI leads with 60%
- [App hosting](https://www.usenotra.com/state-of-ai-search/app-hosting/2026-11?ntr=hiXEwbKyAVT7wcXC): Render leads with 75%
- [Auth](https://www.usenotra.com/state-of-ai-search/auth/2026-11?ntr=hiXEwbKyAVT7wcXC): Clerk leads with 71%
- [Changelog](https://www.usenotra.com/state-of-ai-search/changelog/2026-11?ntr=hiXEwbKyAVT7wcXC): Beamer leads with 55%
- [Postgres](https://www.usenotra.com/state-of-ai-search/postgres/2026-11?ntr=hiXEwbKyAVT7wcXC): Neon leads with 82%

All reports: https://www.usenotra.com/state-of-ai-search

## Where do you rank in AI search?

Notra runs these checks daily for your brand and your prompts, then drafts the content that moves the answer.

[Start for free](https://app.usenotra.com/signup)