Resend Alternative
The email API built
for platforms, not
just projects
Resend is great for developers sending their own email. Beautiful DX, clean API, React Email integration. But platforms that send on behalf of customers need something architecturally different. Ark was built from scratch for exactly that.
Acme Corp
3 domains
StartupXYZ
1 domain
Agency Pro
5 domains
ShopFront
2 domains
Every tenant gets isolated domains, credentials, analytics, and suppression lists
Why platform teams look for Resend alternatives
Resend has a clean API, great documentation, and React Email is genuinely innovative. For a developer sending transactional email from their own app, Resend is one of the best options available. We respect what they've built.
The issue comes when you're a platform. Your customers connect their own domains and send email through your product. Resend has no concept of tenants. Domains live in a flat list at the account level. Webhooks are account-scoped. Suppression lists are account-scoped. Analytics are account-scoped.
This works fine at 5 customer domains. You can track which domain belongs to which customer in your own database. But at 50 domains, the cracks start showing. At 500, you've built a significant internal system just to map Resend's flat structure onto your multi-tenant reality.
Ark is the alternative. Multi-tenancy isn't a bolt-on feature here. It's the entire architecture.
Multi-tenant architecture
Resend's data model is straightforward: Account, Domains, Emails. Everything is scoped to your account. When you add a domain, it goes into a flat list. When you send an email, it's associated with your account. Webhooks fire for all events across all domains.
This is perfectly reasonable for a single-sender use case. But when you're a platform with customers bringing their own domains, you need a layer between "your account" and "the domain" — the customer. Resend doesn't have that layer, so you build it yourself.
Ark takes a fundamentally different approach. The entire system is organized as a white label email API hierarchy: Platform, Tenants, Domains, and Email. When you create a tenant in Ark, everything is scoped to that tenant — their domains, credentials, webhooks, suppression lists, and analytics. There's no artificial limit on tenant count beyond what your plan allows for domains.
Resend approach
Flat domain list · Account-scoped webhooks · Shared suppressions
Ark approach
Tenant A
Tenant B
Tenant C
No tenant limit · Isolated by default · All plans
What you build on Resend
- Customer-to-domain mapping layer
- Webhook routing per customer
- Per-customer suppression logic
- Per-customer analytics aggregation
- Credential isolation between customers
What Ark gives you
- Native tenant-to-domain hierarchy
- Per-tenant and platform-level webhooks
- Automatic per-tenant suppression lists
- Per-tenant analytics and message logs
- Isolated credentials per tenant
Domain management and onboarding
Resend handles domain authentication well for the single-sender case. You add a domain, get back DNS records, and have a 72-hour verification window. The API is clean and the dashboard shows verification status clearly.
But the onboarding experience for your customers is entirely on you. Resend gives you the DNS records. You build the UI that walks your customers through adding those records to their specific DNS provider. Cloudflare? Different steps than GoDaddy. Vercel? Different again.
Ark provides guided domain onboarding. When a tenant adds a domain, Ark auto-detects their DNS provider and shows provider-specific setup steps. There are dedicated guides for Cloudflare, Vercel, Namecheap, Porkbun, GoDaddy, DigitalOcean, Netlify, and more. If something goes wrong after setup, a DomainDNSError webhook event fires so you can alert your customer proactively.
See our complete guide to sending email from your customer's domain for the full technical architecture.
Sending domain
We'll show Cloudflare-specific DNS instructions
Required DNS records
TXTSPF VerifiedCNAMEDKIM VerifiedCNAMEReturn PathPending[email protected]Hard bounceEach tenant's suppression list is independent — Acme's bounces don't affect StartupXYZ
Hard bounce
Instant suppression
Spam complaint
Instant suppression
Soft bounce
18 retries over 48h
Deliverability and suppression management
Resend has a single, account-level suppression list. When an email address hard bounces, it gets added to that list. The problem for platforms: if Customer A sends to an address that bounces, that address is now suppressed for Customer B too — even though Customer B might have a perfectly valid relationship with that recipient.
This is a fundamental architectural limitation. Resend wasn't designed for the case where different senders sharing an account have different recipient relationships. Their suppression model assumes one sender, one list.
Ark provides per-tenant suppression lists, automatically managed. Hard bounces trigger immediate suppression within that tenant. Spam complaints result in instant suppression within that tenant. Soft bounces are retried up to 18 times over roughly 48 hours before the address is suppressed.
On the Scale plan, tenants can get dedicated IPs if they need full IP reputation control. But for most platforms, the combination of per-tenant domains and automatic per-tenant suppression is what actually keeps deliverability healthy.
Pricing comparison
The $9/month difference at the low end buys you the entire multi-tenant layer.
Scale
Resend
Ark
Delta
~10 domains, ~50K emails
Pro $20/mo
Starter $29/mo
+$9/mo
~100 domains, ~100K emails
Scale $90/mo
Growth $99/mo
+$9/mo
~1,000 domains, ~2M emails
Enterprise (custom)
Scale $499/mo
Transparent
Multi-tenant infrastructure
Build it yourself
Included
--
Resend's pricing is straightforward: Free tier at 3K emails/month, Pro at $20/month with 50K emails and 10 domains, Scale at $90/month with 100K emails and 1K domains. Ark's pricing starts at $29/month for the Starter plan with 50K emails and 10 domains. The difference is that Ark includes the entire multi-tenant layer at every tier.
$ curl -X POST \
https://api.arkhq.io/v1/tenants/{id}/messages
{
"to": "[email protected]",
"from": "[email protected]",
"subject": "Order confirmed",
"html": "<h1>Thanks!</h1>"
}
# 200 OK — message queued
/emails/emails/batch/tenants/{id}/domains/tenants/{id}/suppressions/tenants/{id}/webhooks/tenants/{id}/credentials/tenants/{id}/usage/platform/webhooksDeveloper experience
Let's be honest: Resend has one of the best developer experiences in email APIs. Clean documentation, 12+ official SDKs, React Email for building templates with JSX, and an overall polish that makes sending email feel modern. That's a genuine strength.
Ark's DX is built for a different workflow. Where Resend optimizes for "send an email from my app," Ark optimizes for "manage email infrastructure for my customers." The API is tenant-scoped by design — every endpoint operates within a tenant context.
Ark has 66 endpoints covering the full lifecycle: tenants, domains, credentials, messages, webhooks, suppressions, usage tracking, and logs. Official SDKs are available for Python, Node.js, Ruby, and Go. SMTP support is included for self-hosted tools like Listmonk, Coolify, or Metabase.
Where Resend wins
- Template authoring (React Email)
- Broader SDK coverage (12+)
- Broadcast / marketing support
- Inbound email processing
Where Ark wins
- Multi-customer domain mgmt
- Per-tenant everything
- Guided DNS onboarding
- Two-level webhook system
26 MCP tools for AI assistants. Manage email infrastructure using natural language.
Per-customer analytics and debugging
When a customer asks "why didn't my email get delivered?", you need to answer fast. With Resend, analytics are account-scoped — there's no built-in way to filter events by customer or tenant.
Ark provides per-tenant message logs, delivery status tracking, and bounce analysis out of the box. Every message sent by a tenant is queryable through the API with full delivery details.
Webhooks are where Ark really differentiates for platforms. You get two levels: tenant-level webhooks that fire for a specific tenant's events, and platform-level webhooks that fire for all tenants with a tenant_id field in the payload.
{ "event": "delivered",
"tenant_id": "ten_abc123",
"message_id": "msg_xyz",
"recipient": "alice@..." }
Account
Resend webhooks (account-scoped)
∞
Ark webhooks (per-tenant + platform)
The scaling problem: 5 domains vs 500
Resend works great when you start. The complexity grows quietly, then all at once.
Manageable
Track domain-to-customer mapping in a spreadsheet or a simple database table. Route webhooks manually. Suppression collisions are rare.
Cracks show
Webhook routing logic gets complex. Suppression conflicts appear — Customer A's bounce suppresses Customer B's valid recipient. DNS support tickets trickle in.
Internal system
You've built a customer-domain mapping service, webhook fanout, per-customer analytics aggregation, and a DNS troubleshooting runbook. It's a real codebase now.
Your own platform
You're maintaining an internal email platform layer. Edge cases multiply. New hires need to learn the system. It's undocumented infrastructure that only your team understands.
With Ark, you skip all of this. The tenant hierarchy handles customer isolation, webhook routing, suppression scoping, and analytics separation from day one. The code you would have built? You never need to write it.
Who should switch to Ark
Platforms sending on behalf of customers
Your product sends email for your customers using their domains. CRMs, helpdesks, e-commerce platforms, scheduling tools.
Customers bring their own domains
Your customers want to send from their own domain, not yours. Each customer needs their own authenticated sending domain.
Per-customer deliverability needs
You need suppression lists, bounce handling, and reputation tracking that's isolated per customer, not shared across your account.
Spending eng time on multi-tenant glue
You've built (or are building) a layer to map Resend's flat model onto your multi-customer reality. That code is now a maintenance burden.
Getting DNS support tickets
Your customers struggle with DNS setup because you're showing them raw records instead of provider-specific instructions.
Need per-customer billing data
You want to track email usage per customer for billing or fair-use enforcement, without building your own usage aggregation.
When Resend is still the right choice
Resend is a genuinely good product. We're not going to pretend otherwise. There are real use cases where Resend is the better choice over Ark.
If you're sending your own transactional email, Resend is excellent. Clean API, fast delivery, great documentation. You don't need multi-tenancy. You just need to send email reliably from your own domain.
If you love React Email, Resend's integration with React Email is seamless. Build templates with JSX, preview them in the browser, and send them through Resend. Ark doesn't have an equivalent — you'd render React Email to HTML and pass the output to Ark's API.
If you need broadcast or marketing email, Resend has audience management and broadcast sending. Ark is purely transactional email infrastructure — we don't build campaign tools, list management, or bulk sending features.
If you need inbound email processing, Resend supports receiving emails. Ark is send-only. If you need to process incoming email, Resend or a dedicated inbound service is the right choice.
If you want the broadest SDK coverage, Resend has 12+ official SDKs covering most languages and frameworks. Ark has four: Python, Node.js, Ruby, and Go. If your stack isn't covered, you'd use the REST API directly.
If you don't manage customer domains, and your customers all send from your domain (or a subdomain), you probably don't need the multi-tenant architecture that Ark provides.
Also compare
What migrating from Resend looks like
The migration introduces tenant structure to what was previously a flat setup. The biggest win comes at step 5: deleting the multi-tenant code you no longer need.
Create your tenant structure
Map your customers to Ark tenants. Each tenant is created via the API or dashboard. Attach metadata to store your internal customer IDs, billing references, or any custom fields.
Move domain configurations
Add each customer's domain to their tenant. Ark returns the exact DNS records needed. If your customers already have SPF and DKIM configured for Resend, they'll need to update records to point to Ark.
Update send logic — add tenant context
Replace Resend API calls with Ark's REST API. The key difference: every send now includes a tenant ID in the path, scoping the email to the right customer automatically.
Set up webhooks
Configure platform-level webhooks for all tenants, or per-tenant webhooks for customers that need their own endpoints. Events cover delivery, bounces, opens, clicks, and complaints.
Remove your custom multi-tenant layer
The code you built to map domains to customers, route webhooks, scope suppressions, and aggregate per-customer analytics? You can delete it. Ark handles all of that natively.
Most teams complete the migration in a few days for the integration work, plus whatever time their customers need to update DNS records.
FAQ
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