Skip to content
Toolradar
Helo logo

Helo

Claim this toolEditor reviewed

Send transactional and broadcast emails via a simple REST API

From $5/mo (free plan available)
FreemiumEmailDeveloper ToolsAPI ToolsTransactional Email
Visit Website
Tracked since2026

The Bottom Line

Price
From $5/mo (free plan available). Compare plans

Key facts

  • Simple REST API and SDKs for Ruby, JavaScript, C#, Go, and Python to send transactional and broadcast emails.
  • Bootstrapped company with a team of email infrastructure veterans focused on reliability and affordability.
  • Supports email templates with variable substitution for personalized messages at scale.

Pros

  • Developer-friendly API with extensive SDK language support
  • Bootstrapped and independent, aligning incentives with user needs
  • Affordable pricing compared to many competitors

Cons

  • Relatively new service with a smaller community and ecosystem than established providers like SendGrid or Mailgun
  • Limited advanced features like A/B testing or sophisticated analytics compared to larger competitors

What is Helo?

Editorial review
Helo is an email API and SMTP service designed for developers who need to send transactional and broadcast emails with ease. It offers a straightforward REST API and SDKs in multiple programming languages, including Ruby, JavaScript, C#, Go, and Python, so you can integrate email sending into your app in minutes. The platform supports both transactional emails (like password resets and notifications) and broadcast campaigns to large lists via a single API call, with features like idempotency keys and templates for personalization. The company behind Helo is bootstrapped by a small team of experienced email infrastructure and developer tools experts, many of whom previously worked at Postmark. As an independent, investor-free business, Helo aims to provide a calm, reliable, and affordable email service that remains focused on its users rather than external growth targets. The team emphasizes straightforward pricing and a no-nonsense approach to deliverability and support.
how we evaluateSourcehelohq.com ↗

Key Features

  • Transactional email sending (password resets, confirmations, notifications)
  • Broadcast email campaigns to large lists with a single API call
  • SDKs available for Ruby, JavaScript (TypeScript), C#, Go, and Python
  • Idempotency keys to prevent duplicate sends
  • Template-based email personalization with variable substitution

Pricing Plans

Pricing checked Oct 3, 2026

Helo plans and prices, checked October 2026
PlanPriceDetails
Free

Free

  • 1,000 free emails for testing
One Plan

$5 / mo

  • Unlimited users
  • Detailed analytics
  • Unlimited domains
+3 more
  • Multi-tenant sending
  • Unlimited webhooks
  • Outstanding support
Calculate your costView full pricing

Is Helo worth the price?

Great value

Helo's pricing is exceptionally generous for a transactional email API, with the One Plan at $5/month offering unlimited everything, far cheaper than most competitors' per-email models.

The Free tier provides 1,000 test emails, which is fair for evaluation. This is best for small teams or developers who need a simple, low-cost email sending solution without worrying about overages.

How Helo's pricing compares

At $5/mo, billing unit not specified, Helo is the most affordable of its 4 comparable direct competitors.

Helo
$5
Nylas
$5
MailerSend
$7
SendGrid
$19.95
Mailgun
$90

Entry paid plan, monthly. Pricing checked Oct 3, 2026.

Reviews

Improve Your Thinking Patterns Using ChatGPT cover
$99Free with your review

Review Helo, get a free AI guide

Share your experience and we will send you Improve Your Thinking Patterns Using ChatGPT, free.

Write a review

Best Helo Alternatives

Top alternatives based on features, pricing, and user needs.

View full list →
Mailgun logo
MailgunFreemium

Send, parse, and validate emails with a reliable developer API

4.1
SendGrid logo
SendGridFreemium

Deliver transactional and marketing emails with powerful APIs

4.1
MailerSend logo
MailerSendFreemium

Intuitive email API and SMTP email sending with high deliverability and easy integration.

4.3
Postmark logo
PostmarkFreemium

Reliable, fast transactional email delivery for developers

4.7
Courier logo
CourierFreemium

The multichannel notification platform for transactional and lifecycle messages.

4.5
Nylas logo
NylasPaid

Integrate email, calendar, and meetings into your application with universal APIs.

3.4
Resend logo
ResendFreemium

Send transactional and marketing emails with a powerful API

4.8
See all email tools →

Still deciding?

Most buyers shortlist 2 or 3 tools before committing. Pull a side-by-side comparison or browse the full alternatives shortlist below.

All Helo alternatives7+ tools ranked, pricing + verdict per pickHelo vs MailgunHead-to-head: features, pricing, who winsHelo vs SendGridHead-to-head: features, pricing, who winsHelo vs MailerSendHead-to-head: features, pricing, who wins

Explore More

Best Email ToolsBest Developer ToolsBest API ToolsBest Transactional Email ToolsBest Free EmailBest Free Developer ToolsBest Free API ToolsBest Free Transactional Email

Helo FAQ

How does Helo handle sending password reset emails?

Helo supports transactional emails like password resets and notifications through its REST API. Developers can send these emails by making a single API call with the appropriate template and recipient data, ensuring reliable delivery.

How does Helo compare to SendGrid for developers?

Helo offers a more affordable and developer-friendly alternative to SendGrid, with SDKs in multiple languages and a straightforward REST API. However, Helo is a newer service with a smaller ecosystem and fewer advanced features like A/B testing compared to SendGrid.

What trade-offs should developers consider when choosing Helo over more established email services?

Helo is a relatively new service with a smaller community and ecosystem than established providers like SendGrid or Mailgun. It also lacks some advanced features such as A/B testing and sophisticated analytics that larger competitors offer.

Which teams benefit most from using Helo for their email sending needs?

Teams of developers who need a simple, reliable email API for transactional and broadcast emails benefit most from Helo. Its straightforward pricing and independent, bootstrapped nature appeal to teams that want a calm, no-nonsense email service without external growth pressures.

Does Helo include a free tier for developers to test the API?

Yes, Helo includes a free tier that allows developers to test the API and send a limited number of emails. Paid plans are available for higher usage and additional features, with straightforward pricing.

Can Helo send broadcast campaigns to large email lists using a single API call?

Yes, Helo supports broadcast campaigns to large lists via a single API call. This allows developers to send personalized emails to many recipients efficiently using templates and idempotency keys.

Which programming languages does Helo provide SDKs for?

Helo provides official SDKs for Ruby, JavaScript, C#, Go, and Python. These SDKs simplify integration with the REST API, enabling developers to start sending emails quickly in their preferred language.

How does Helo's idempotency key feature help prevent duplicate email sends?

Helo's idempotency key feature ensures that duplicate API calls do not result in duplicate email sends. By providing a unique key with each request, developers can safely retry failed sends without worrying about sending the same email multiple times.

Source: helohq.com

Guides & Articles

Best Transactional Email Services in 2026

Expert guide

Best Free Email Clients in 2026

Expert guide

Best Business Email Providers in 2026

Expert guide