Templates

Handlebars

Minimal logic template language used across email systems.

See alternatives ↗ Visit handlebarsjs.com ↗

overview

Handlebars is a Mustache-compatible template language that compiles templates into JavaScript functions. It is not email-specific, but it is common in ESP template systems, internal notification renderers, and server-side email pipelines.

for growth and lifecycle teams

Growth work lives or dies on targeting and measurement. What matters is whether behavioral triggers can be built without engineering time, whether the event stream supports attribution past the open, and whether deliverability holds when broadcast volume shares a reputation with product email.

Against behavior-triggered journeys, broadcasts, and winback campaigns measured on revenue, Handlebars covers none of the capabilities this audience leans on (scheduling, event stream, the suppressions API, and multi-tenant support), so it fits only where those needs are genuinely absent.

Scheduling: No
Event stream: No
Deliverability: Not applicable; template language only.
Operating since: Not published
Suppressions API: No
Best published rate per 1,000: Tiers not published in comparable form
Multi-tenant: No
Free tier: Free, MIT-licensed
Starts at: Free

deliverability

Not applicable; template language only.

best for

Teams that need a small, stable variable and conditional layer inside an existing email renderer.

not great for

Teams expecting an end-to-end responsive email framework.

pros

› Simple syntax with wide adoption
› Mustache compatibility eases migration from simpler template systems
› MIT-licensed and easy to embed in server-side renderers

cons

› No email-client layout system, inliner, preview server, or compatibility layer
› Helper sprawl can turn simple templates into application logic
› Needs a separate HTML email framework for responsive layout

Features at a glance

API	No
SMTP	No
SDKs	node
Webhooks	No
Templates	basic
React Email	No
Batch send	No
Scheduled send	No
Suppressions	No
Multi-tenant	No
Inbound parsing	No
Event stream	No
Idempotency keys	No
Dedicated IP	No

Appears in rankings

#05 →

6 Best Email Template Engines (2026), Tested

Good variable and conditional layer inside existing renderers, but not an email layout framework.

#11 →

12 Best Open-Source Email Tools (2026), Tested

Simple MIT-licensed template layer used across many email renderers.