Private CDN vs Public CDN

Internal CDNs.

Overview

Private versus public CDN is a build-versus-buy decision specialised to the content-delivery layer. Public CDNs (Cloudflare, Fastly, CloudFront) are the right choice for almost everyone; private CDNs make sense only at the scale where the operational tax of running edge infrastructure is repaid by the per-byte savings. The decision turns on volume, control requirements, and the team’s willingness to operate edge POPs.

• Public CDN. Managed edge POPs, mature security and DDoS protection, per-byte pricing. The right default for almost everyone.
• Private CDN. Full control over edge logic, hardware, and routing. Justified only at very large scale or for specialised security/regulatory requirements.
• Cost trade-off. Public CDNs are cheap at low volume, expensive at high volume. The crossover point is where build-versus-buy actually flips.
• Operational fit plus control. Running a private CDN is a long-term commitment to edge infrastructure expertise; public CDNs spare the team that cost.

The approach

Three habits keep the choice rational: public CDN as the default, private CDN justified only at very large scale or with specialised requirements, and a documented rationale that survives team turnover.

• Public CDN default. Cloudflare, Fastly, CloudFront. Mature, managed, fast to enable.
• Private only at very large scale. Justification requires both crossover-point math and a long-term operational commitment.
• Per-volume cost comparison. Real numbers at projected volumes. Vendor decks are not the source of truth.
• Documented rationale plus operational fit. Per-team the why-this-choice; per-team the willingness to operate edge if private was chosen.

Why this compounds

Each correct CDN decision compounds across every byte served. The team’s content-delivery expertise deepens; the cost story stays predictable; the operational surface stays matched to actual capacity.

• Operational fit. Right CDN for the workload means infrastructure load matches team capability.
• Cost efficiency. Right pricing model matched to volume cuts the bill at every scale.
• Engineering culture matures. Build-versus-buy decisions made on data teach the team how to make the next one.
• Year-one investment, year-two habit. First decision takes care. By the third major infrastructure choice, the methodology is settled.