The Billion-Email Question: Build vs. Buy for Email Infrastructure
CTOs and CEOs eventually face the question: When does it make sense to stop paying for an ESP and build our own email infrastructure?
Historically, the break-even point was thought to be ~100M emails/month. But with Laneful’s flat-rate pricing model ($80 per ~10M emails, including deliverability automation), the ROI curve has shifted.
Assumptions Behind the Cost Comparison
- Laneful: $80 per 10M emails/month (1 lane per ~10M). Laneful Overview
- AWS SES: $0.10 per 1k emails ($100 per 1M). AWS SES Pricing
- SendGrid / Mailgun: $0.80–$0.90 per 1k emails (higher volume pricing not public). SendGrid Pricing, Mailgun Pricing
- In-House (KumoMTA): Based on KumoMTA Performance Update.
- 16-core ARM (~$418/mo) → ~110M emails/month
- 36-core ARM (~$1,398/mo at $1.94/hr) → ~150M emails/month
- 7 × 36-core (~$9,786/mo) → ~1B emails/month
- Staffing (required for in-house):
- Deliverability Specialist: $100k/year (~$8.3k/mo)
- Ops Engineer: $120k/year (~$10k/mo)
- Total staff baseline: $18.3k/mo
Cost Comparison at Scale
| Monthly Volume | Laneful | AWS SES | SendGrid | Mailgun | In-House (KumoMTA + Staff) |
|---|---|---|---|---|---|
| 10M | $80 | $1,000 | $9,000 | $8,000 | ~$18.7k |
| 100M | $800 | $10,000 | $90,000 | $80,000 | ~$18.7k |
| 500M | $4,000 | $50,000 | $450,000 | $400,000 | ~$22.5k |
| 1B | $8,000 | $100,000 | $900,000 | $800,000 | ~$28.1k |
Decision Guide by Volume
| Monthly Volume | Best Approach | Why |
|---|---|---|
| < 100k | ESP low tier | SendGrid/Mailgun low tiers or Laneful Relay ($5). |
| 100k – 1M | Laneful lanes | Predictable cost ($80 per lane); no deliverability staff needed. |
| 1M – 100M | Laneful | $800 at 100M vs $18k+ in-house or $10k–$90k with others. |
| 100M – 1B | Laneful | Still only $8k at 1B vs $28k in-house or $100k+ elsewhere. |
| > 1B | Hybrid / In-House | Only here can infra + staffing begin to beat Laneful. |
Key Takeaway
With Laneful’s flat-rate model, it’s nearly impossible to justify in-house infrastructure until you exceed 1 billion emails/month.
Infrastructure itself (via KumoMTA) is cheap, but staffing costs dominate. For everyone under that scale such as startups, SaaS, and enterprises alike, Laneful is the clear ROI winner.