May 02, 2025·8 min
From CDN to Platform: How Cloudflare’s Edge Expanded
Learn how Cloudflare’s edge grew from CDN caching to security and developer services as more traffic shifts to the network perimeter.
Learn how Cloudflare’s edge grew from CDN caching to security and developer services as more traffic shifts to the network perimeter.
An edge network is a set of servers distributed across many cities that sit “close” to end users. Instead of every request traveling all the way back to your company’s origin servers (or cloud region), the edge can answer, inspect, or forward that request from a nearby location.
Think of it like placing helpful staff at the entrances of a venue rather than handling every question at the back office. Some requests can be handled immediately (like serving a cached file), while others are safely routed onward.
The perimeter is the boundary where outside internet traffic first meets your systems: your website, apps, APIs, and the services that protect and route them. Historically, many companies treated the perimeter as a thin doorway (DNS and a load balancer). Today it’s where the busiest and riskiest interactions happen—logins, API calls, bots, scraping, attacks, and sudden spikes.
As more work moves online and more integrations rely on APIs, it’s increasingly practical to funnel traffic through the perimeter so you can apply consistent rules—performance optimizations, security checks, and access controls—before requests hit your core infrastructure.
This article follows a progression: performance first (CDN), then security at the edge (DDoS, WAF, bot controls, Zero Trust), and finally developer tooling (running code and handling data closer to users).
It’s written for non-technical decision-makers—buyers evaluating vendors, founders making trade-offs, and PMs who need the “why” and “what changes,” without needing to read networking textbooks.
A traditional CDN (Content Delivery Network) started with a simple promise: make websites feel faster by serving content from a location closer to the visitor. Instead of every request traveling back to your origin server (often a single region or data center), the CDN keeps copies of static files—images, CSS, JavaScript, downloads—at many points of presence (PoPs). When a user asks for a file, the CDN can respond locally, reducing latency and taking pressure off the origin.
At its core, a “CDN-only” setup focuses on three outcomes:
This model is especially effective for static sites, media-heavy pages, and predictable traffic patterns where the same assets are requested over and over.
In the early days, teams evaluated CDNs with a handful of practical metrics:
These numbers mattered because they translated directly into user experience and infrastructure cost.
Even a basic CDN affects how requests reach your site. Most commonly, it’s introduced through DNS: your domain is pointed to the CDN, which then routes visitors to a nearby PoP. From there, the CDN may act as a reverse proxy—terminating the connection from the user and opening a separate connection to your origin when needed.
That “in the middle” position matters. Once a provider is reliably in front of your origin and handling traffic at the edge, it can do more than cache files—it can inspect, filter, and shape requests.
Many modern products aren’t mostly static pages anymore. They’re dynamic applications backed by APIs: personalized content, real-time updates, authenticated flows, and frequent writes. Caching helps, but it can’t solve everything—especially when responses vary per user, depend on cookies or headers, or require immediate origin logic.
That gap—between static acceleration and dynamic application needs—is where the evolution from “CDN” to a broader edge platform begins.
A big shift in how the internet is used has pushed more requests to “the edge” (the network perimeter) before they ever touch your origin servers. It’s not just about faster websites anymore—it’s about where traffic naturally flows.
HTTPS everywhere is a major driver. Once most traffic is encrypted, network middleboxes inside a corporate network can’t easily inspect or optimize it. Instead, organizations prefer to terminate and manage TLS closer to the user—at an edge service built for that job.
APIs have also changed the shape of traffic. Modern apps are a constant stream of small requests from web frontends, mobile clients, partner integrations, and microservices. Add bots (good and bad), and suddenly a large portion of “users” aren’t humans at all—meaning traffic needs filtering and rate controls before it hits application infrastructure.
Then there’s the everyday reality of mobile networks (variable latency, roaming, retransmits) and the rise of SaaS. Your employees and customers are no longer “inside” a single network boundary, so security and performance decisions move to where those users actually connect.
When applications, users, and services are spread across regions and clouds, there are fewer reliable places to enforce rules. Traditional control points—like a single data center firewall—stop being the default path. The edge becomes one of the few consistent checkpoints that most requests can be routed through.
Because so much traffic passes through the perimeter, it’s a natural place to apply shared policies: DDoS filtering, bot detection, WAF rules, TLS settings, and access controls. This reduces “decision-making” at each origin and keeps protections consistent across apps.
Centralizing traffic at the edge can hide origin IPs and reduce direct exposure, which is a meaningful security win. The trade-off is dependency: edge availability and correct configuration become critical. Many teams treat the edge as part of core infrastructure—closer to a control plane than a simple cache.
For a practical checklist, see /blog/how-to-evaluate-an-edge-platform.
A traditional CDN started as “smart caching”: it stored copies of static files closer to users and fetched from the origin when needed. That helps performance, but it doesn’t fundamentally change who “owns” the connection.
The big shift happens when the edge stops being just a cache and becomes a full reverse proxy.
A reverse proxy sits in front of your website or app. Users connect to the proxy, and the proxy connects to your origin (your servers). To the user, the proxy is the site; to the origin, the proxy looks like the user.
That positioning enables services that aren’t possible with “cache-only” behavior—because every request can be handled, modified, or blocked before it reaches your infrastructure.
When the edge terminates TLS (HTTPS), the encrypted connection is established at the edge first. That creates three practical capabilities:
Here’s the mental model:
user → edge (reverse proxy) → origin
Putting the edge in the middle centralizes control, which is often exactly the goal: consistent security policies, simpler rollouts, and fewer “special cases” at each origin.
But it also adds complexity and dependency:
This architectural shift is what turns a CDN into a platform: once the edge is the proxy, it can do far more than cache.
A DDoS (Distributed Denial of Service) attack is simply an attempt to overwhelm a site or app with so much traffic that real users can’t get through. Instead of “hacking in,” the attacker tries to clog the driveway.
Many DDoS attacks are volumetric: they throw huge amounts of data at your IP address to exhaust bandwidth or overload network devices before a request ever reaches your web server. If you wait to defend at your origin (your data center or cloud region), you’re already paying the price—your upstream links can saturate, and your firewall or load balancer can become the bottleneck.
An edge network helps because it puts protective capacity closer to where the traffic enters the internet, not just where your servers live. The more distributed the defense, the harder it is for attackers to “pile up” on a single choke point.
When providers describe DDoS protection as “absorbing and filtering,” they mean two things happening across many points of presence (PoPs):
The key benefit is that the worst of the attack can be handled upstream of your infrastructure, reducing the chance your own network—or cloud bill—becomes the casualty.
Rate limiting is a practical way to prevent any single source—or any single behavior—from consuming too many resources too quickly. For example, you might limit:
It won’t stop every kind of DDoS on its own, but it’s an effective pressure valve that reduces abusive spikes and keeps critical routes usable during an incident.
If you’re evaluating edge-based DDoS protection, confirm:
Once basic DDoS filtering is in place, the next layer is protecting the application itself—especially the “normal-looking” requests that carry malicious intent. This is where a Web Application Firewall (WAF) and bot management become the day-to-day workhorses at the edge.
A WAF inspects HTTP/S requests and applies rules designed to block common patterns of abuse. The classic examples are:
Instead of relying on your app to catch every bad input, the edge can filter many of these attempts before they reach origin servers. That reduces risk and also cuts down noisy traffic that wastes compute and logs.
Bots can be helpful (search engine crawlers) or harmful (credential stuffing, scraping, inventory hoarding, fake sign-ups). The key difference isn’t just automation—it’s intent and behavior. A real user’s session tends to have natural timing, navigation flow, and browser characteristics. Malicious bots often generate high-volume, repetitive requests, probe endpoints, or mimic user agents while behaving unnaturally.
Because the edge sees huge volumes across many sites, it can use broader signals to make smarter calls, such as:
A practical rollout is to begin in monitor (log) mode to see what would be blocked and why. Use that data to tune exceptions for known tools and partners, then gradually tighten policies—moving from alerting to challenges and finally to blocks for confirmed bad traffic. This reduces false positives while still improving security quickly.
Zero Trust is easier to understand when you drop the buzzwords: don’t trust the network—verify each request. Whether someone is in the office, on hotel Wi‑Fi, or on a home network, access decisions should be based on identity, device signals, and context—not on “where” the traffic originates.
Instead of putting internal apps behind a private network and hoping the perimeter holds, Zero Trust access sits in front of the application and evaluates every connection attempt. Typical uses include:
A key shift is that access decisions tie directly to your identity provider: SSO for centralized logins, MFA for step-up verification, and group membership for simple policy rules (“Finance can access the billing tool; contractors cannot”). Because these checks happen at the edge, you can enforce them consistently across locations and apps.
A common mistake is treating Zero Trust as a one-to-one VPN replacement and stopping there. Removing the VPN can improve usability, but it doesn’t automatically fix weak identity practices, over-broad permissions, or missing device checks.
Another pitfall is “approve once, trust forever.” Zero Trust works best when policies stay specific (least privilege), sessions are time-bound, and logs are reviewed—especially for privileged tools.
APIs changed the game for edge networks because they multiplied the number of “doors” into a business. A single website might have a few pages, but a modern app can expose dozens (or hundreds) of API endpoints used by mobile clients, partner integrations, internal tools, and automated jobs. More automation also means more machine-driven traffic—legitimate and abusive—hitting the perimeter constantly.
APIs are predictable, high-value targets: they often return structured data, power logins and payments, and are easy to call at scale. That makes them a sweet spot where performance and security need to work together. If the edge can route, cache, and filter API traffic close to the requester, you reduce latency and avoid wasting origin capacity on junk requests.
Edge platforms typically offer API gateway-style functions such as:
The goal isn’t to “lock everything down” at once—it’s to stop obviously bad traffic early, and make the rest easier to observe.
API abuse often looks different from classic website attacks:
Prioritize three practical features: good logs, rate limits by token (not just by IP), and clear, consistent error responses (so developers can fix clients quickly, and security teams can distinguish failures from attacks). When these are built into the edge, you get faster APIs and fewer surprises at the origin.
Edge compute means running small pieces of code on servers close to your users—before a request travels all the way back to your origin application. Instead of only caching responses (the classic CDN job), the edge can now make decisions, transform requests, and even generate responses on the spot.
Most early wins come from “thin logic” that needs to happen on every request:
Because this happens near the user, you cut round trips to the origin and reduce load on core systems—often improving both speed and reliability.
Edge compute helps most when the logic is lightweight and time-sensitive: routing, gating access, shaping traffic, and enforcing rules consistently across regions.
Your origin (or a central backend) is still the better place for heavy application work: complex business logic, long-running jobs, large dependencies, or anything that needs deep database access and strong consistency across users.
Edge runtimes are intentionally constrained:
The practical approach is to treat edge compute as a fast “front desk” for your application—handling checks and decisions early—while leaving the “back office” work to the origin.
Edge compute is only half the story. If your function runs close to users but has to fetch data from a far-away region on every request, you lose most of the latency benefit—and you may introduce new failure points. That’s why edge platforms add data services designed to sit “near” compute: key-value (KV) stores, object storage for blobs, queues for async work, and (in some cases) databases.
Teams typically start with simple, high-read data:
The pattern is: reads happen at the edge, writes flow back into a system that replicates.
“Eventual consistency” usually means: after a write, different locations might temporarily see different values. For product teams, this shows up as “Why did one user see the old flag for 30 seconds?” or “Why did a logout not invalidate everywhere instantly?”
Practical mitigations include:
Look beyond speed claims:
Edge storage works best when you’re explicit about what must be correct now versus what can be correct soon.
As an edge network grows beyond caching, a predictable pattern appears: consolidation. Instead of stitching together separate providers for DNS, CDN, DDoS protection, WAF, bot controls, and app access, organizations move toward a single control plane that coordinates how traffic enters and moves through the perimeter.
The practical driver is operational gravity. Once most inbound traffic already passes through one edge, it’s simpler to attach more decisions to that same path—routing, security policies, identity checks, and application acceleration—without adding extra hops or more vendors to manage.
Consolidation can make teams faster and calmer:
The same centralization introduces real tradeoffs:
Treat the edge like a platform, not a tool:
Done well, consolidation reduces complexity day-to-day—while governance keeps that convenience from turning into hidden risk.
Choosing an edge platform isn’t just picking “a faster CDN.” You’re selecting where critical traffic is inspected, accelerated, and sometimes executed—often before it reaches your apps. A good evaluation ties platform features to your real constraints: user experience, risk, and developer velocity.
Start by writing down what you actually need in three buckets:
If you can’t connect a “must-have” to a measurable outcome (e.g., fewer incidents, lower latency, reduced origin load), treat it as optional.
If you’re building new apps while you modernize the perimeter, also evaluate how your development workflow connects to this edge posture. For example, teams using Koder.ai to vibe-code and ship React web apps (with Go + PostgreSQL backends, or Flutter mobile clients) can take advantage of an edge platform for consistent TLS termination, WAF policies, and rate limiting in front of rapidly iterated releases—while still keeping the option to export source code and deploy where they need.
Ask for specifics, not feature names:
Pick one app (or one API) with meaningful traffic. Define success metrics like p95 latency, error rate, cache hit ratio, blocked attacks, and time-to-mitigate. Run in phased mode (monitor → enforce), and keep a rollback plan: DNS switch-back, bypass rules, and a documented “break glass” path.
Once you have results, compare plan tradeoffs on /pricing and review related explainers and deployment stories in /blog.
An edge network is a distributed set of servers (points of presence) placed in many cities so requests can be handled closer to users. Depending on the request, the edge might:
The practical result is lower latency and less load and exposure on your origin infrastructure.
The perimeter is the boundary where internet traffic first reaches your systems—your website, apps, and APIs—often through DNS and an edge reverse proxy. It matters because that’s where:
Centralizing controls at the perimeter lets you apply consistent performance and security rules before traffic reaches your core services.
A classic CDN focuses on caching static content (images, CSS, JS, downloads) at edge locations. It improves speed mainly by reducing distance and offloading your origin.
A modern edge platform goes further by acting as a full reverse proxy for most traffic, enabling routing, security inspection, access controls, and sometimes compute—whether or not the content is cacheable.
DNS is often the simplest way to put a CDN/edge provider in front of your site: your domain points to the provider, and the provider routes users to a nearby PoP.
In many setups the edge also acts as a reverse proxy, meaning users connect to the edge first, and the edge connects to your origin only when needed. That “in the middle” position is what enables caching, routing, and security enforcement at scale.
When the edge terminates TLS, the encrypted HTTPS connection is established at the edge. That enables three practical capabilities:
It increases control—but also means edge configuration becomes mission-critical.
You should evaluate a CDN using metrics that tie to user experience and infrastructure cost, such as:
Pair these with origin-side metrics (CPU, request rate, egress) to confirm the CDN is actually reducing pressure where it matters.
Edge mitigation is effective because many DDoS attacks are volumetric—they try to saturate bandwidth or network devices before requests reach your application.
A distributed edge can:
Defending only at the origin often means you pay the price (saturated links, overloaded load balancers, higher cloud bills) before mitigation kicks in.
Rate limiting caps how many requests a client (or token) can make in a time window so one source can’t consume disproportionate resources.
Common edge use cases include:
It won’t solve every DDoS, but it’s a strong, easy-to-explain control for abusive spikes.
A WAF inspects HTTP requests and applies rules to block common application attacks (like SQLi and XSS). Bot management focuses on identifying and handling automated traffic—both good bots (e.g., search crawlers) and harmful ones (scraping, fake sign-ups, credential stuffing).
A practical rollout is:
Zero Trust means access decisions are based on identity and context, not on being “inside the network.” At the edge, it commonly looks like:
A common pitfall is treating it as a simple VPN replacement without tightening permissions, session duration, and device checks—those are what make it safer over time.