At a Glance
Choosing a Zero Trust Network Access (ZTNA) vendor depends on what you’re protecting. Zscaler leads for large enterprises needing full SASE convergence. Cloudflare Access and Twingate suit fast, developer-friendly deployments. Tailscale is the top pick for DevOps teams connecting engineers to infrastructure. Teleport solves credentialed infrastructure access specifically. NetFoundry stands apart as the only option built to secure machine-to-machine traffic, APIs, and AI agents natively — not just human users logging into a VPN replacement.
Zscaler, Cloudflare, Tailscale, Twingate, Teleport, NetFoundry — six vendors, six pitches, and every one of them calls themself “Zero Trust.” But not all of them use the concept of “Zero Trust” the same way, and that gap is exactly what makes shopping this category so frustrating.
Some verify your identity and then route your traffic through their own cloud to inspect it. Others build a direct, encrypted tunnel between you and the resource and stay out of the way. A few are built for IT admins protecting a workforce; one is built around credentials rather than network paths; one is built to protect applications, APIs, and AI agents that never had a human user to begin with.
Before we compare them head-to-head, it’s worth settling what “Zero Trust” actually means — because the disagreement between vendors on that definition is central to the story.
What Is Zero Trust Network Access (ZTNA)?
At NetFoundry, we define Zero Trust Network Access as an approach to secure connectivity where nothing — no user, device, or application — is trusted by default, even if it’s already inside the corporate network. Instead of a VPN’s all-or-nothing tunnel, ZTNA continuously verifies identity and context for every single connection and grants access only to the specific resource requested, never the whole network.
The category split matters more than the marketing suggests. Some ZTNA platforms build a direct, peer-to-peer path between the user and the resource, with a control plane that handles authentication but never touches the actual traffic. Others act as a broker: your traffic always flows through the vendor’s cloud edge, where it gets inspected before being forwarded. Both are Zero Trust; they just make different tradeoffs between performance, control, and how much you’re trusting a third party with your traffic.
How We Compared These Vendors
We looked at five things for each platform:
- The underlying connectivity architecture (peer-to-peer, broker, or embedded)
- Who the platform is actually built for
- Deployment complexity
- Whether it extends beyond human users to machine workloads and AI agents
- Where it fits in a broader security stack
None of this is paid or sponsored; it’s built from current vendor documentation and independent comparison research, linked throughout.
Zscaler
Zscaler uses what it calls “inside-out” connectivity — both the user and the application connect outbound to Zscaler’s cloud, which brokers the session so neither side ever exposes an open inbound port or a real IP address. Both Zscaler and Cloudflare terminate the connection and perform deep, real-time inspection of traffic — including encrypted traffic — as it passes through their proxy before reaching the application. That’s a meaningfully different model from a traditional VPN, and it comes bundled with Zscaler’s broader Zero Trust Exchange: secure web gateway, cloud sandboxing, and data loss prevention all in the same platform.
Best For: Large enterprises that want Zero Trust delivered as one piece of a comprehensive, cloud-native security platform.
Strengths:
- Full SASE/SSE convergence, so ZTNA isn’t a bolt-on but part of one unified security stack
- Mature, global cloud infrastructure with strong compliance credentials
- Deep visibility into who’s accessing what, including previously-unknown internal apps
Trade-Offs:
- Priced and built for enterprise scale — smaller teams often find the cost and setup complexity heavier than they need
- Adopting Zscaler for ZTNA means adopting the whole Zero Trust Exchange. Even teams that only need a simple VPN replacement end up buying into a full SASE platform
- Every session transits Zscaler’s cloud, so you’re trusting their edge with your traffic
Neither is disqualifying for the enterprise buyer Zscaler is built for — but it’s worth knowing that adopting Zscaler means rearchitecting around their cloud. Certain other solutions (like NetFoundry) deploy without infrastructure changes and can run fully self-hosted if you’d rather not depend on any vendor’s cloud at all.
Cloudflare
Cloudflare Access delivers ZTNA through more than 300 points of presence on the same anycast network Cloudflare already uses for its CDN and DDoS mitigation, which makes it one of the quickest Zero Trust platforms to stand up if you’re already a Cloudflare customer. It supports both an agent-based client and fully clientless, browser-based access — useful for contractors or BYOD scenarios where installing software isn’t realistic.
Best For: Teams that want fast, clientless deployment on top of infrastructure they’re already using for CDN or DDoS protection.
Strengths:
- Fast time-to-value for existing Cloudflare customers
- Agentless access options for unmanaged devices and third parties
- A large, well-distributed edge network with minimal new infrastructure to deploy
Trade-Offs:
- Broker model, so your traffic transits Cloudflare’s edge for inspection — a real tradeoff even where the security model is sound
- Policy granularity, while solid, doesn’t go as deep as platforms purpose-built around enterprise security governance
For teams already on Cloudflare, that speed of deployment usually outweighs the tradeoffs — though it’s worth noting Cloudflare’s Zero Trust is one feature set inside a much larger platform. Other solutions like NetFoundry are purpose-built for Zero Trust and never route traffic through a third-party cloud to get there.
Tailscale
Tailscale takes a fundamentally different architectural approach than the broker-based platforms in this list. By its own description, it functions more like a mesh VPN with continuous re-authorization than a traditional ZTNA proxy. Built on WireGuard, Tailscale creates a private mesh network where devices connect directly to each other whenever possible, with the control plane handling authentication and policy but carrying almost none of the actual traffic.
Best For: Engineering and DevOps teams connecting developers to infrastructure, where simplicity and low latency matter more than heavyweight enterprise controls.
Strengths:
- Peer-to-peer design keeps latency low and traffic off any vendor’s cloud
- Access control lives in a version-controllable ACL file, which engineering teams tend to prefer over a sprawling admin console
- Fast, simple setup compared to traditional ZTNA proxies
- End-to-end encrypted by default — like NetFoundry, Tailscale never terminates or decrypts sessions in transit
Trade-Offs:
- Not a traditional ZTNA proxy, so it lacks some of the deep enterprise governance and compliance tooling security teams managing thousands of users often need
- Direct connectivity depends on successful NAT traversal, falling back to a relay when it isn’t available
For a small, technical team, these are edge cases; for large, distributed workforces with strict compliance needs, they’re worth planning around. This juncture is where bottoms-up, developer-first design starts running into ceilings that NetFoundry’s enterprise identity model and purpose-built AI/MCP gateway are designed to clear.
Twingate
Twingate is a ZTNA platform built around outbound-only connections, so no inbound firewall ports ever need to open. Like Zscaler and Cloudflare, it’s primarily focused on human user access, though it offers some machine-to-machine ZTNA functionality — but unlike Zscaler and Cloudflare, Twingate doesn’t terminate or decrypt sessions. It’s end-to-end encrypted, similar to NetFoundry. Where it diverges from Tailscale is philosophy: Twingate leans into a visual, admin console-driven approach to defining exactly which resource a group can reach.
Best For: Teams that want Tailscale’s lightweight deployment model with a more structured, GUI-driven policy engine for defining resource-level access.
Strengths:
- No inbound ports required, thanks to the outbound-only Connector model
- A more structured console for defining and reviewing granular, resource-level access, which security teams often find easier to audit than a flat ACL file
- Straightforward migration path from legacy VPN setups
Trade-Offs:
- Traffic can route through Twingate’s relay infrastructure when direct peer-to-peer isn’t available, but the session itself remains end-to-end encrypted regardless of path
- Built primarily around securing human user access rather than machine-to-machine or embedded application traffic
Twingate is a solid fit for straightforward VPN replacement for IT and DevOps teams. NetFoundry plays further up-market, with a stronger story for the AI-agent and machine-to-machine use cases that Twingate wasn’t built to address.
Teleport
Teleport takes a different angle than everything else on this list: instead of governing the network path to a resource, it governs the credential used to access it. The Teleport Infrastructure Identity Platform replaces static credentials and standing privileges — passwords, API keys, long-lived tokens — with short-lived, cryptographically signed certificates for accessing SSH, Kubernetes, databases, and internal applications, extended to human, machine, and AI agent identities alike.
Best For: Engineering teams that want to eliminate standing credentials and long-lived secrets for accessing infrastructure (SSH, Kubernetes, databases) and extend that same model to AI agents.
Strengths:
- Certificate-based, ephemeral access means there’s no long-lived password or API key sitting around to leak or rotate
- A dedicated Agentic Identity Framework for securing AI agents that need to access infrastructure resources
- Deep audit trail and session recording, which compliance-heavy environments like financial services tend to value
Trade-Offs:
- Governs who can open a session and with what privileges — it doesn’t create or secure the network path that session travels over
- Built primarily around infrastructure access management rather than a full network overlay
That’s a genuinely different layer of the stack than a network overlay: Teleport decides who’s allowed to open a session, while NetFoundry decides whether a network path to that session exists at all. The two are complementary more often than competitive, and worth evaluating together rather than as an either/or.
NetFoundry
Every platform above shares one assumption: there’s a human at the other end of the connection, logging in through a client or a browser. NetFoundry starts from a different premise.
Built on the open source OpenZiti platform, NetFoundry embeds Zero Trust directly into an application, API, or device — as code, not as a network overlay bolted on afterward. That’s the difference between ZTNA for humans and Zero Trust for machines: the same identity-based, no-open-ports model, but built to secure workload-to-workload and AI-agent traffic that never touches a login screen at all.
Best For: Organizations that need Zero Trust to extend past human users into applications, APIs, IoT devices, and AI agents — without routing traffic through a third-party cloud to get there.
Strengths:
- No open inbound firewall ports anywhere in the path — nothing for an attacker to scan
- Authentication based on cryptographically verified identity rather than IP address or user login, checked before a session is ever established
- Application-embedded Zero Trust for developers who want the control plane inside their own code
- Native support for securing AI agents, MCP servers, and LLM deployments — a use case none of the other platforms were built for
- Deployable self-hosted via OpenZiti, or hosted by NetFoundry — you’re never forced to trust a black box you can’t inspect
Trade-Offs:
- Newer entrant to enterprise security conversations than Cisco-era incumbents
- More capability than needed for teams that just want simple human-user remote access with no machine-workload requirements — if your Zero Trust problem is entirely “get my remote employees securely onto SaaS apps,” that’s a narrower job than NetFoundry is built for, and Tailscale or Twingate are simpler direct fits
If your Zero Trust strategy needs to reach past the login screen into APIs, IT/OT connectivity, and AI agents, NetFoundry is solving a problem none of the other five were built for.
Quick Comparison Table
| Vendor | Architecture | Best For | Notable Strength |
|---|---|---|---|
| Zscaler | Cloud broker | Large enterprise, full SASE | Comprehensive security platform |
| Cloudflare | Cloud broker | Fast, clientless deployment | Massive edge footprint |
| Tailscale | Peer-to-peer mesh | DevOps / engineering teams | Simplicity, low latency |
| Twingate | Relay-based | GUI-driven granular access | Outbound-only Connectors |
| Teleport | Credential / PAM | Infrastructure access (SSH, K8s, DBs) | Short-lived certificates, no standing secrets |
| NetFoundry | Embedded / overlay | APIs, IoT, AI agents, machine identity | No open ports, app-embedded |
Which Zero Trust Vendor Is Right for You?
If you’re only securing human users logging into SaaS and internal apps and you’re already standardized on a broader SASE platform, Zscaler lets you extend that existing investment without adding a vendor.
If fast, lightweight deployment for developers or contractors is the priority, Cloudflare, Tailscale, or Twingate are built specifically for that narrower job.
If the goal is eliminating standing credentials for infrastructure access (SSH, Kubernetes, databases), Teleport solves that specific layer well, and it’s worth pairing with rather than replacing whatever secures the network path underneath it.
None of the five, however, reach the layer connecting your applications, APIs, IoT devices, and AI agents to each other. That’s the layer where NetFoundry operates. If your Zero Trust strategy needs to cover more ground than any one of these addresses on its own — humans and machines, login screens and machine-to-machine traffic, without routing everything through a third-party cloud to get there — that’s the gap only NetFoundry is built to close.
Get Started
If your Zero Trust strategy stops at the login screen, it’s missing everything your applications, APIs, and AI agents are doing behind it. Talk to NetFoundry about securing the connections the vendors above weren’t built to see — or start a free trial and see what “no open ports” actually looks like in your own environment.
FAQ
What is Zero Trust Network Access (ZTNA)?
Zero Trust Network Access is a security approach where no user, device, or application is trusted by default — every connection is continuously verified based on identity and context before access is granted, and only to the specific resource requested, not the entire network. NetFoundry builds this on identity-based authorization rather than IP addresses, which is why our platform never needs to open an inbound firewall port to work.
What’s the difference between a VPN and ZTNA?
A VPN puts a user on the network; ZTNA connects a user only to the specific applications they’re authorized for, which limits what an attacker can reach even if one connection is compromised. NetFoundry takes this further than most ZTNA vendors by never opening an inbound port in the first place, rather than just restricting what’s reachable after a connection is made.
Which zero trust vendor is best for enterprises?
It depends on what you’re securing. Zscaler is a strong, mature choice for enterprises standardizing human-user access as part of a broader SASE platform, and Teleport is a strong choice if the need is specifically about eliminating standing credentials for infrastructure access like SSH and Kubernetes. NetFoundry is the option built to extend the same Zero Trust principles to APIs, IoT devices, and AI agents that never had a human login to begin with — a layer the other platforms weren’t designed to reach.
Is NetFoundry a Tailscale or Zscaler alternative?
NetFoundry can replace either, but it’s built to solve a broader problem than both. Where Tailscale and Twingate focus on connecting engineers to infrastructure, and Zscaler focuses on brokering enterprise user traffic through its cloud, NetFoundry embeds Zero Trust directly into applications — covering human users and machine-to-machine traffic in the same platform, without routing anyone’s data through a third-party cloud to get there.
Can Zero Trust protect AI agents and MCP servers?
AI agents and MCP servers create connections that look nothing like a human logging into an app — there’s no login screen, and the “user” is often another piece of software making autonomous decisions. NetFoundry was built specifically to secure these: it requires cryptographically verified identity for every agent, workload, or MCP server before a connection is even established, with no open inbound port for an attacker to find in the first place.
About NetFoundry
NetFoundry is a leader in Secure Workload Connectivity, founded by the inventors and maintainers of OpenZiti, the world’s most widely used open source zero trust platform. NetFoundry’s Identity-First Reachability™ gives businesses the only identity-first zero trust fabric for every AI, API, site, and machine interaction — securing and connecting AI agents, MCP servers, LLMs, APIs, and OT/IoT infrastructure alongside traditional enterprise workloads, all with no open inbound ports, no VPNs, and no firewall changes. NetFoundry secures billions of sessions for critical infrastructure on three continents and supports Fortune 10 companies across regulated industries including healthcare, financial services, and energy.
