Email API Benchmarks (by Knock): Finally, an Objective Referee for Developer Email Choices

2026-03-12 | ProductHunt | 108 votes

30-Second Quick Take

What is it?: Knock has released a set of Email API performance benchmarks, comparing delivery rates, latency, and pricing across major providers like SendGrid, Postmark, AWS SES, Resend, and Mailgun. Simply put, it helps you stop guessing when choosing an email service.

Is it worth it?: Yes. If you're building a product that requires transactional emails (sign-ups, password resets, order notifications), these benchmarks can save you days of research. However, keep in mind this is produced by Knock—they are a notification infrastructure platform themselves, so there's a bit of a "referee is also a player" vibe to the data.

Three Questions for You

Does this matter to me?

• Target Users: Developers integrating email into products, tech leads choosing providers, and SaaS teams.
• Is that me?: If your product sends transactional emails (password resets, order confirmations, alerts), you are the target user.
• When would I use this?:
  • New project selection → Use these benchmarks to decide instantly.
  • Low delivery rates → Compare to see if it's time to switch.
  • Cost optimization → Compare costs per 1,000 emails; differences can be as high as 18x ($0.10 vs $1.80).
  • Pure content/No email needs → This doesn't apply to you.

Is it useful?

ROI Judgment: If you are about to choose or change email providers, spending 30 minutes on this benchmark is absolutely worth it. It’s free, data-driven, and comparative.

Is it satisfying?

The "Aha" Moment:

• Finally, someone put the "real" performance of various email APIs side-by-side instead of just letting providers brag about themselves.
• Data-driven decisions mean you don't have to guess performance based on marketing fluff.

Key Finding:

Postmark has a 98.7% delivery rate and 1.2s delivery time—but costs $1.20-$1.80 per 1k. AWS SES is only $0.10 per 1k but has a ~90% delivery rate. Is that 8.7% gap worth 18x the price? It depends on your use case.

Real User Feedback:

"Knock is extremely reliable, we never had even one issue with Knock itself." — G2 User "Clean, consistent, and well-documented APIs make integration seamless even without the SDK." — G2 User "Love the developer experience and in-app components but $250/month is steep for a startup." — Sequenzy Review

For Indie Hackers

Core Benchmarks: Who is Fast, Accurate, and Cheap?

Tech Stack (Knock Platform Itself)

• Backend: Elixir/Erlang (High concurrency + fault tolerance, based on phone system routing architecture)
• Frontend: React component library (Telegraph, open-source)
• Real-time: WebSocket
• SDKs: JavaScript, React, Android, iOS
• Design Philosophy: API-first, Dashboard-second

Open Source Status

• Knock core platform is NOT open-source; it is a commercial SaaS.
• SDKs and components are open-source: react-notification-feed, knock-android.
• Looking for an open-source alternative? → Novu (38K+ GitHub stars, self-hostable, though features aren't as complete as Knock's cloud version).
• Difficulty of DIY benchmarks: Low—you could use a Python script to call various APIs, record latency and bounce rates. The value is in the scale and sample size of their testing.

Business Model

• Monetization: SaaS subscription (billed by notification volume).
• Pricing: Free 10K/mo → Starter $250/mo for 50K/mo → Enterprise (Custom).
• Key Detail: Knock is a "routing layer." You still need to connect downstream services like SendGrid/Twilio, which is an additional cost.
• Clients: Vercel, Webflow, Zapier, Amplitude.

Giant Risk

Email performance benchmarks have no moat; anyone can do them. However, Knock's core competency isn't benchmarks—it's the notification orchestration platform. The risk from giants comes from AWS (SNS+SES+EventBridge) and Twilio (Segment+SendGrid). Currently, giant solutions feel like "parts," whereas Knock provides the "glue."

For Product Managers

Pain Point Analysis

• Core Problem: Developers choose email providers based on "reputation + marketing," lacking objective performance data.
• Deeper Pain Point: Teams need to integrate multiple channels (email+push+SMS+in-app). Fragmented APIs lead to high maintenance costs.
• Pain Level: Medium-frequency essential need—every SaaS needs to send mail, but the selection decision usually only happens once.

User Persona

• Primary Users: Backend developers (selection + integration), Tech Leads (architectural decisions), Growth Engineers (optimizing email reach).
• Scenarios: New product selection, cost optimization of existing solutions, troubleshooting delivery issues.

Feature Breakdown

Competitor Comparison

Key Takeaways

1. Content as Marketing: Knock captures developer attention through utility-based content like "Email API benchmarks"—which is more valuable than a standard blog post.
2. "Referee + Player" Strategy: Establish industry standards/benchmarks first, then offer your solution as the best way to manage them.
3. Generous Free Tier: 10K notifications/month is enough for many early-stage products.

For Tech Bloggers

Founder Story

• Sam Seely (CEO): Santa Clara University grad, worked at Accenture, Percolate (PM), and was Head of Product at Frame.io (acquired by Adobe for over $1B).
• Chris Bell (CTO): Active in the Elixir community, runs an Elixir podcast, and has deep experience in high-concurrency systems.
• The "Why": The founders believe the "last mile" of delivery is solved (SendGrid, Twilio), but an "orchestration layer" to tie all channels together was missing—that's Knock's positioning.

Controversies / Discussion Angles

• The "Referee + Player" Conflict: Knock is a notification platform benchmarking email APIs—is the data biased?
• The $250/month Pricing Debate: The jump from free to paid is massive, sparking community discussion: "Where is the middle tier?"
• Open Source vs. Commercial: How does Knock compete with the 38K-star Novu open-source solution?
• Is Email Over-Engineered?: For products that only need to send simple emails, is an orchestration layer like Knock overkill?

Hype Data

• 108 PH Votes: Solid for a developer tool.
• PH History: Knock has had 2 successful launches on PH.
• Twitter: @knocklabs, ~900 tweets, moderate developer community activity.
• Client Quality: Vercel, Zapier, and Webflow are users—this is more convincing than any vote count.

Content Suggestions

• Angle: "Stop Guessing Your Email Provider—A 2026 Performance Comparison."
• Trend Opportunity: Combine the rise of Resend and the cost-effectiveness of AWS SES into a selection guide.

For Early Adopters

Pricing Analysis

Hidden Cost: Knock only handles routing. You still need to pay SendGrid ($20+/mo) or AWS SES (very cheap). Total cost = Knock + Downstream Provider.

Getting Started

• Setup Time: Official claim is "hours not months"; Amplitude completed a full migration in 4 weeks.
• Learning Curve: Moderate—high-quality API docs and plug-and-play components, but workflow logic takes a moment to grasp.
• Steps:
  1. Sign up at knock.app and get your API Key.
  2. Install SDK: npm install @knocklabs/client.
  3. Configure your downstream email provider (e.g., SendGrid).
  4. Create a notification workflow in the Dashboard.
  5. Call knock.workflows.trigger() in your code.

Pitfalls and Complaints

1. Pricing Gap: No middle ground between Free and $250/mo. If you hit 10,001 notifications, it's an awkward jump.
2. Lack of Automated Testing: No robust way to test Knock workflows within a CI/CD pipeline.
3. No Declarative Config: Developers want to manage this via Terraform/IaC; it's not supported yet.
4. Double Billing: You have to budget for both Knock and your downstream provider.

Security and Privacy

• Data Storage: Cloud-based (hosted by Knock).
• API Key Tiers: Publishable Key (frontend) + Secret Key (backend).
• Rate Limiting: Tiered by endpoint, consistent across all plans.
• SOC 2: Supported on Enterprise plans.

Alternatives

For Investors

Market Analysis

• Email API Market: $3.1B (2024) → $8.2B (2033), 11.4% CAGR.
• Transactional Email API: $2.1B (2024) → $7.5B (2033), 14.2% CAGR.
• Drivers: Cloud adoption, AI integration (personalization/A/B testing), surge in online transactions, and compliance (GDPR/HIPAA).
• Geography: North America holds 40% share; APAC is the fastest-growing (13.2% CAGR).

Competitive Landscape

Timing Analysis

• Why Now?: SaaS explosion → surge in notification needs → multi-channel orchestration becomes a necessity.
• Tech Maturity: Elixir/Erlang is proven for high-concurrency (WhatsApp used Erlang).
• Market Readiness: Developers are highly comfortable with "Infrastructure-as-a-Service" (Stripe/Twilio paved the way).
• AI Boost: Knock has launched an MCP Server, allowing AI tools like Cursor/Claude Code to manage notification workflows directly.

Team Background

• Sam Seely (CEO): Accenture → Percolate PM → Head of Product at Frame.io (Acquired by Adobe for $1B+).
• Chris Bell (CTO): Elixir community leader with deep technical roots.
• Signal: The Frame.io pedigree suggests experience in scaling from zero to a major exit.

Funding Status

• Seed: $6M (Led by Afore Capital).
• Series A: $12M (Led by Craft Ventures).
• Total: $18M.
• Angel Investors: Guillermo Rauch (Vercel CEO), Scott Belsky (Behance Co-founder).
• 2024 Growth: 3x revenue growth, 10x notification volume growth.

Conclusion

One-Sentence Verdict: The Email API Benchmarks are a clever content marketing move by Knock—providing value to developers via objective data while showcasing their deep understanding of the email ecosystem. The real story isn't the benchmarks, but Knock's positioning as the "notification orchestration layer."

Resource Links

2026-03-12 | Trend-Tracker v7.3