Comparison

Sentroy vs Resend

Resend is a polished managed email API. Sentroy is an open platform where transactional email is one of several bundled services (mail, storage, auth, env vault). This page is an honest side-by-side so you can pick the right one for your team — and a migration snippet if you decide to switch.

Quick comparison#

The five questions most teams actually care about when picking a transactional email vendor.

	Sentroy	Resend
Pricing model	Flat platform tier; mail volume not metered per send	Per-email metered ($/email above free tier)
Self-hostable	Yes — Postfix/Dovecot/Rspamd stack ships as IaC	No — managed only
Open formats	MJML templates, raw MIME, IMAP-backed inbox	React Email components, raw HTML
Lock-in	Low — standards-based, exportable, can stand up your own copy	Moderate — proprietary API + dashboard, no self-host path
Bundled with other products	Storage + auth + env vault + status pages, one tenant	Email-only; pair other services yourself

What is the same#

The places these two products meaningfully overlap.

Both expose a clean REST API for transactional send with Bearer-token auth.
Both handle DKIM, SPF, and DMARC for verified domains.
Both deliver webhook events for sent, bounced, opened, clicked, and unsubscribed.
Both support per-domain webhook scoping with HMAC-signed payloads.
Both have first-class TypeScript SDKs with full typings.
Both let you template once and reuse across sends.

What is different#

Honest differences in both directions — neither product is strictly better.

Where Sentroy is different

Self-hostable end-to-end: the same Postfix/Dovecot/Rspamd stack we run in production ships as an IaC bundle.
Multilingual templates as a first-class shape ({tr, en, ...} per field) — no extra plumbing to ship locale-aware email.
IMAP-backed inbox API for reading replies, not just sending. Threading, folders, mark-as-read all included.
Same access token also reaches storage, auth projects, and env vault — one credential per company.
Flat pricing — send volume isn't the meter, so high-volume bursts don't spike the bill.

Where Resend is different

Larger ecosystem of pre-built React Email templates and integrations.
Longer track record on deliverability — more years of IP warmup and reputation history.
Generous free tier for early-stage projects (3k emails / month at the time of writing).
More polished dashboard for non-developers reviewing delivery metrics.
SOC 2 Type II audited; some regulated buyers require this checkbox.

When to pick Sentroy#

Concrete situations where Sentroy is the better call.

You want one vendor for email + file storage + auth, and you don't want to wire three SDKs and three billing relationships together.
You ship a multilingual product and want template translations to live in the template itself, not in your application code.
Your compliance team needs the option to self-host the mail stack on infrastructure you control (EU residency, HIPAA, etc.).
You need both send and inbox in the same API — e.g. a support inbox that reads replies and threads them with the original transactional send.

When to stick with Resend#

Cases where staying on Resend is the right call — we'd rather you pick the right tool than churn after a month.

You only need email and you already have storage / auth solved elsewhere — the bundle isn't a draw.
You've invested heavily in React Email components and your team prefers JSX over MJML.
You need a vendor with a multi-year audited deliverability record on day one of a regulated launch.

Migration#

One operation, both APIs side by side. Most ports take an afternoon — the SDK shape is intentionally familiar.

Sending a transactional email with a template and variables:

before.ts — Resendts

import { Resend } from "resend"

const resend = new Resend(process.env.RESEND_API_KEY)

await resend.emails.send({
  from: "Acme <onboarding@acme.dev>",
  to: "user@example.com",
  subject: "Welcome to Acme",
  react: WelcomeEmail({ name: "Jane" }),
})

after.ts — Sentroyts

import { Sentroy } from "@sentroy-co/client-sdk"

const sentroy = new Sentroy({
  baseUrl: "https://sentroy.com",
  companySlug: "acme",
  accessToken: process.env.SENTROY_ACCESS_TOKEN!,
})

await sentroy.send.email({
  from: "onboarding@acme.dev",
  to: "user@example.com",
  subject: "Welcome to Acme",
  domainId: "<acme-domain-id>",
  templateId: "<welcome-template-id>",
  variables: { name: "Jane" },
})

The Sentroy template lives on the server, so the body markup ships once and renders with whichever variables you pass at send time. Multilingual templates auto-pick the locale via the lang field.

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