SendGrid Alternative
The email API built
for platforms
SendGrid is a solid email service for companies sending their own email. But if you're a SaaS platform where your customers send email through you, you've probably already hit its limits. Ark was built from scratch for exactly that use case.
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 SendGrid alternatives
If you run a SaaS product that sends email on behalf of your customers, you know the pattern. A customer signs up, adds their domain, and expects to send transactional email through your platform. Password resets, order confirmations, notifications. The stuff that has to work.
With SendGrid, you end up duct-taping this together. You create subusers for each customer, manually configure domain authentication, build your own analytics dashboards per customer, and hope that one customer's spam complaint doesn't drag everyone else's deliverability down with it.
It works, sort of, until you have 20 customers. Then 50. Then you realize you've built a fragile email management layer on top of a service that was never designed for multi-tenant use.
Ark is the alternative. Multi-tenancy isn't a bolt-on feature here. It's the entire architecture.
Multi-tenant architecture
SendGrid's approach to multi-tenancy is the subuser system. Each subuser gets their own sending reputation, API keys, and some degree of isolation. In practice, subusers were designed for internal teams within a single company, not for scaling to hundreds or thousands of external customers.
First, subusers require SendGrid's Pro plan, which starts at $89.95/month. You get a default limit of 15 subusers. Need more? You have to contact sales and negotiate. Each subuser also shares the parent account's email credits, so you need to build your own usage tracking and enforcement on top of SendGrid's API.
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.
SendGrid approach
Shared credits · 15 subuser limit · Pro plan required
Ark approach
Tenant A
Tenant B
Tenant C
No tenant limit · Isolated by default · All plans
SendGrid subusers
- Requires Pro plan ($89.95/mo+)
- Default limit of 15 subusers
- Shared email credits across subusers
- Built for internal teams, not external customers
Ark tenants
- Available on all plans (from $29/mo)
- No limit on number of tenants
- Per-tenant domains, credentials, suppressions & logs
- Built for platforms with external customers
Domain management and onboarding
Domain authentication is where multi-tenant email gets painful. Every customer who wants to send from their own domain needs SPF, DKIM, and ideally DMARC records configured correctly. With SendGrid, you authenticate domains through the dashboard or API, get back a set of DNS records, and then... that's it. Your customer has to figure out how to add those records to their DNS provider.
Ark provides guided domain onboarding. When a tenant adds a domain, Ark detects their DNS provider and shows them the exact steps for their specific provider. There are dedicated setup guides for Cloudflare, Vercel, Namecheap, Porkbun, GoDaddy, DigitalOcean, Netlify, and more.
After the records are added, your customer calls the verify endpoint. Ark checks the DNS configuration and confirms everything is set up correctly. If something is wrong, the API tells you what's missing. There's also a DomainDNSError webhook event that fires if DNS records become invalid after initial setup.
For the full technical walkthrough of domain setup, DNS configuration, and reputation isolation, see our guide to sending email from your customer's domain.
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
Deliverability comes down to two things: the reputation of the domain you're sending from, and the reputation of the IP you're sending through. Since each tenant in Ark sends from their own domain, they naturally have their own domain reputation. Tenants share IP pools — just like SendGrid and every other provider.
Where Ark actually helps with deliverability is suppression management. Every tenant gets their own suppression list, automatically managed. Hard bounces trigger immediate suppression. Spam complaints result in instant suppression. Soft bounces are retried up to 18 times over roughly 48 hours before the address is suppressed.
This all happens per-tenant. If a recipient bounces for Tenant A, that doesn't suppress the same address for Tenant B. With SendGrid subusers, you need to manage this yourself — building per-subuser suppression logic on top of SendGrid's account-level suppression.
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
SendGrid requires the Pro plan for multi-tenant features. Ark includes everything on every plan.
SendGrid Pro
Required for multi-tenant
- 15 subusers (default limit)
- 1 dedicated IP included
- Up to 1,000 teammates
- 7-day email activity
- Guided DNS onboarding
- Per-tenant analytics
- Two-level webhooks
- Unlimited tenants
Ark Starter
Full multi-tenant features
- Unlimited tenants
- Up to 10 domains
- Unlimited team members
- Full message logs per tenant
- Guided DNS onboarding
- Per-tenant analytics
- Two-level webhooks
- 50K emails/month
As you scale, Ark's Growth plan ($99/month) supports 100 domains and 250K emails. The Scale plan ($499/month) supports 1,000 domains and 2M emails with dedicated IP options.
$ 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
SendGrid has been around since 2009 and has extensive documentation. Their API is well-documented with client libraries for most languages. That's a genuine advantage of a mature product.
That said, the API surface area is massive. You'll find v2 and v3 endpoints, inconsistent naming conventions, and features that overlap in confusing ways.
Ark's API is focused on multi-tenant email. There are 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.
Ark also ships with SMTP support for platforms that need it. Self-hosted tools like Listmonk, Coolify, or Metabase can send through Ark by changing one SMTP configuration.
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 that question fast. With SendGrid, email activity search gives you 3 days of history on Essentials or 7 days on Pro.
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@..." }
5
SendGrid webhook endpoints (Pro)
∞
Ark webhooks (per-tenant + platform)
Who should switch to Ark
SaaS platforms
Your customers connect their domains and send transactional email through your product. CRMs, helpdesks, e-commerce platforms, scheduling tools.
White-label products
You need email infrastructure that's invisible to end users. Your customers see their own domain, analytics, and deliverability metrics.
Developer-led platforms
You want a clean, tenant-scoped API where everything — domains, credentials, webhooks, suppressions — is organized per customer without building it yourself.
Growing platforms
You've outgrown SendGrid's 15-subuser default and don't want to negotiate custom limits. You need pricing that scales predictably.
When SendGrid is still the right choice
We're not going to pretend Ark is the right tool for everyone. SendGrid has genuine strengths that make it the better choice for certain use cases.
If you're a single company sending your own email, SendGrid is a proven, reliable option. You don't need multi-tenancy. You just need a good email API with high deliverability. SendGrid has been doing this for over 15 years, they have established relationships with inbox providers, and their infrastructure is battle-tested at massive scale.
If you need marketing automation features, SendGrid has Marketing Campaigns with drag-and-drop editors, A/B testing, segmentation, and automation. Ark is purely transactional email infrastructure. We don't build campaign tools, template editors, or contact management.
If you need SOC 2 Type II certification for compliance, SendGrid has it. Ark is newer and focused on building the best multi-tenant email infrastructure first. Enterprise compliance certifications are on the roadmap but not available yet.
If you're already on SendGrid and it's working fine, don't switch for the sake of switching. Ark is for teams that have hit SendGrid's multi-tenant limitations and need something purpose-built.
Also compare
What migrating from SendGrid looks like
Switching email providers is never trivial, but the migration from SendGrid to Ark is straightforward because the concepts map cleanly.
Create your Ark account and set up tenants
Map your SendGrid subusers to Ark tenants. Each tenant gets created via the API or dashboard. Attach metadata to store your internal customer IDs.
Add sending domains per tenant
Use the API to add each customer's domain to their tenant. Ark returns exact DNS records needed. Customers follow guided setup for their specific DNS provider.
Update your API integration
Replace SendGrid API calls with Ark's REST API or SMTP endpoint. The message format is similar. If you use SMTP, it's a configuration change.
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.
Run both in parallel, then cut over
Send a percentage of traffic through Ark while keeping SendGrid active. Monitor deliverability and events. Once confident, move all traffic to Ark.
Most teams complete the migration in a few days for the integration work, plus whatever time their customers need to update DNS records.
FAQ
Done wrestling with subusers?
Try the email API where multi-tenancy is the architecture, not a workaround. Start your 7-day free trial. No credit card needed.