SMTPfastvsResend
Two developer-first email APIs compared: pricing per volume, contacts and broadcasts, inbound email, MCP and Terraform support, and where each one actually fits.
SMTPfast
A lean email API with transactional sending, inbound receiving, contacts, segments and broadcasts included. Free tier of 3,000 emails/month; paid plans from $9. Ships a hosted MCP server, an official Terraform provider and an Agent Skill.
Visit websiteResend
The best-known developer email API of the last few years. React Email templates, SDKs for most languages, inbound email, broadcasts, and a hosted MCP server with a broad tool surface. Free tier of 3,000 emails/month (100/day); Pro from $20.
Visit websiteSMTPfast and Resend answer the same question: how does a developer send email through an API without fighting an enterprise dashboard from 2012? Both are API-first, both have generous free tiers of 3,000 emails a month, and both now ship hosted MCP servers so AI agents can send through them. Every number below is stated plainly so you can verify it against both public pricing pages.
The honest difference is shape. Resend is the larger, more mature product with a bigger ecosystem: official SDKs across many languages, React Email for templates, and SOC 2 compliance messaging aimed at scaling startups. SMTPfast is smaller and priced like it wants your side project and your startup's first two years: contacts, segments and broadcasts are included in every tier rather than sold as a separate marketing product, and the paid tiers undercut Resend at most volumes.
This comparison walks the numbers per volume tier, the feature surface (including the newer agent-facing pieces like hosted MCP servers and Terraform support), and the scenarios where each is the right call.
Feature Comparison
| Feature | SMTPfast | Resend |
|---|---|---|
| Cost | ||
| Free tier | 3,000 emails/mo with no daily cap, 1,000 contacts, 2 broadcasts/mo, no card; invite-gated | 3,000 emails/mo capped at 100/day, 1 domain, instant signup |
| Price at 10,000 emails/mo | $9/mo (Starter, 10k emails, 5,000 contacts) | $20/mo (Pro, includes 50k headroom) |
| Price at 50,000 emails/mo | $19/mo (Growth) | $20/mo (Pro) |
| Price at 200,000 emails/mo | $49/mo (Scale) | $160/mo tier on Scale pricing |
| Features | ||
| Transactional sending API | REST API with idempotency, batch sending, scheduling, inline cid images, automatic plain-text part, share links for sent emails | REST API, batch sending, scheduling, React Email rendering |
| SMTP relay | SMTP interface available alongside the REST API | SMTP interface (smtp.resend.com) alongside the REST API |
| Contacts, segments and broadcasts | Included in every plan, limits scale per tier | Audiences and Broadcasts available; generous on paid plans |
| Newsletter signup forms | Hosted signup forms that feed contacts and segments directly | No hosted forms; add contacts via API, CSV import or manually |
| Inbound email | Per-domain receiving on paid plans: one MX record, dashboard Inbound page, Resend-compatible receiving API, email.received webhook, 30-day retention, virus and spam verdicts | Inbound receiving with webhooks and a receiving API |
| Ecosystem | ||
| Official SDKs and templates | REST plus OpenAPI spec; community SDKs | SDKs for most major languages, React Email |
| Hosted MCP server for AI agents | Yes, /api/mcp, 12 scoped tools including received mail, API-key auth, speaks the 2026-07-28 spec | Yes, mcp.resend.com, broad tool surface, OAuth or API key |
| Public changelog | /changelog with every customer-visible change since launch | Detailed changelog, several entries a week |
| Operations | ||
| Infrastructure as code | Official Terraform provider | Community Terraform provider |
| Deliverability protection | Staged warm-up, suppression management, URL reputation scanning, and broadcasts that pause themselves on a complaint or bounce spike | Managed IP pools, suppression management, deliverability tooling |
| Team workspaces | Teams with roles, seats, audit log, shared domains and owner-level billing | Team members per workspace on paid plans |
| Security | ||
| Compliance posture | Standard practices; no formal certification published | SOC 2 Type II messaging for security reviews |
| API key scopes | Per-key scopes chosen in the dashboard (send, read, domains, contacts, inbound, ...) and editable later | Full access or sending-only keys, optionally limited to one domain |
Cost
Features
Ecosystem
Operations
Security
Pros and Cons
Strengths
- Lower price at most volumes: 50,000 emails for $19/month, 200,000 for $49/month
- Contacts, segments and broadcasts included in every tier, no separate marketing add-on
- Hosted newsletter signup forms included, no separate form tool needed
- Hosted MCP server (8 scoped tools) plus an official Terraform provider
- Free tier includes 3,000 emails/month, 1,000 contacts and broadcasts, no credit card
- Gradual sending warm-up for new accounts protects deliverability by default
Weaknesses
- Free tier is invite-gated: you request access or pay to skip the queue
- Fewer official SDKs; the API is straightforward REST but you write more glue yourself
- No inbound email receiving yet (planned)
- Younger product with a smaller community and template ecosystem
Strengths
- Mature ecosystem: official SDKs, React Email, extensive docs and examples
- Inbound email receiving, not just sending
- Hosted MCP server with a broad tool surface and OAuth sign-in for web clients
- Instant free tier signup, no invite queue
- SOC 2 compliance posture aimed at companies with security review processes
Weaknesses
- More expensive at volume: 100,000 emails is $35 (Pro cap) and Scale starts at $90
- Free tier capped at 100 emails/day, which blocks bursty use
- Broadcast/audience features grew out of transactional and are priced accordingly at scale
- Broad MCP tool surface means more to audit before handing it to an autonomous agent
Decision Matrix
Pick this if...
Transactional plus newsletter on one bill from day one
React Email component templates
Cheapest 50k-200k emails/month
Inbound email receiving
Hosted MCP server for agents
Terraform-managed email infrastructure
SOC 2 for procurement
Instant free signup for a weekend experiment
Scoped API keys per integration
Use Cases
A side project or early startup that also needs a newsletter
SMTPfast includes contacts, segments and broadcasts in every tier including free, so transactional plus newsletter runs on one bill from day one. The $9 and $19 tiers keep that true as you grow.
A product built on React that lives on polished email templates
React Email plus Resend's SDKs is the smoothest template workflow in the industry. If your team already thinks in components, nothing else feels as native.
High-volume transactional sending on a budget
At 200,000 emails a month the gap is $49 versus $160. If email volume grows faster than revenue, the pricing curve matters more than ecosystem width.
You need to receive email, not just send it
Both receive email now: Resend with inbound webhooks, SMTPfast with per-domain receiving on paid plans, a Resend-compatible receiving API and an email.received webhook. If you already integrate Resend receiving, the SMTPfast endpoints and objects have the same shape.
AI agents sending email on your behalf
Both ship hosted MCP servers, which puts them ahead of nearly every other email provider. SMTPfast's 8 scoped tools are easier to audit before giving an agent the keys; Resend's broader surface lets an agent manage templates, audiences and domains too. Pick by how much you want the agent to control.
An enterprise security review stands between you and shipping
Resend's SOC 2 posture and larger track record clear procurement conversations that a younger product will get stuck in.
Verdict
Resend is the safer default for teams that want the biggest ecosystem: SDKs everywhere, React Email, and a compliance story for security reviews. SMTPfast is the value pick and the simpler one to reason about: contacts and broadcasts included everywhere, inbound email on paid plans with a Resend-compatible receiving API, meaningfully lower prices from 10k to 200k emails a month, scoped API keys, a scoped hosted MCP server, and an official Terraform provider. If you need React Email or a SOC 2 answer, pick Resend. If your bill is driven by volume, or you want transactional, newsletter and inbound in one product without a marketing-tier upsell, SMTPfast costs less at every step and does all three.
Our Recommendation
Choose SMTPfast if your bill is volume-driven, you want transactional plus newsletter plus inbound on one plan, or you want a Terraform-managed setup with scoped keys and a small, auditable agent toolset. Choose Resend if you need React Email templates, official SDKs in your language, or a SOC 2 answer for procurement. Both are REST APIs with hosted MCP servers and compatible receiving endpoints, so switching later is mostly DNS records and a changed base URL.
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