What Is VMware ESXi? Versions, Licensing & Free Option

This is a working reference on VMware ESXi — the same material our ESXi server support team uses when assessing hosts. It covers what ESXi is, how it relates to vSphere and vCenter, the current versions including the rename to ESX in 9.0, licensing since Broadcom ended and then partially restored the free tier, support dates, and hardware requirements.

What is VMware ESXi

VMware ESXi is a type-1 (bare-metal) hypervisor. It installs directly onto server hardware — no underlying Windows or Linux operating system — and partitions that hardware into virtual machines, each with its own virtual CPU, memory, disk, and network devices. Because it runs on the metal rather than inside a host OS, it carries less overhead and a smaller attack surface than type-2 hypervisors such as VMware Workstation or VirtualBox.

ESXi consists of the VMkernel — the core that schedules CPU and memory and handles storage and network I/O — plus management agents and a host client web UI. It has no general-purpose console OS; the earlier product that did, VMware ESX (with a Linux-based service console), was retired after version 4.1 in favor of the slimmer ESXi architecture. The product history is documented on Wikipedia's VMware ESX entry.

An ESXi server, on its own, is a single managed host: you connect to its Host Client in a browser, create VMs, and assign resources. Clustering, live migration (vMotion), high availability, and distributed resource scheduling all require vCenter Server on top.

ESXi vs. vSphere vs. vCenter

The three names are frequently conflated. The relationship is:

In short, ESXi is the engine, vCenter is the control plane, and vSphere is the product line that contains both. A fuller breakdown of the suite, its editions, and licensing is in our VMware vSphere overview.

Current versions: ESXi 8.0 and the rename to ESX 9

Two host lines are current in 2026:

• ESXi 8.0 Update 3 — the current 8.x train, serviced through lettered patch releases (8.0 U3e, U3f, and later). Release notes for each build are on Broadcom TechDocs.
• ESX 9.0 — shipped with VMware Cloud Foundation 9.0 and vSphere Foundation 9.0, generally available June 17, 2025. Starting with version 9.0, Broadcom renamed the hypervisor from ESXi back to ESX, reviving the pre-2010 name. Documentation for the 9.x line is under vSphere 9.0 on TechDocs.

Build numbers do not encode the version; Broadcom maintains the full build-to-version mapping in knowledge base article 316595. A complete release-by-release list, from ESX 1.x through the current builds, is in our ESXi versions reference.

Free ESXi: removed in 2024, partially restored

The free vSphere Hypervisor tier (free ESXi 7.x and 8.x) was discontinued on February 12, 2024, shortly after Broadcom completed its acquisition of VMware and moved the portfolio from perpetual licenses to subscriptions. Existing free installs kept running, but the download and free license keys were withdrawn.

Broadcom reversed course in April 2025: ESXi 8.0 Update 3e was released with a free hypervisor edition again, announced in Broadcom knowledge article 399823. The free edition is downloaded from the Broadcom Support Portal (registration required) and applies to the 8.0 U3 line; Broadcom has not announced a free edition of ESX 9.

Paid ESXi is no longer sold as a standalone perpetual license. It is licensed per CPU core (16-core minimum per CPU) through subscription bundles — primarily VMware vSphere Foundation and VMware Cloud Foundation — with a smaller vSphere Standard tier available through partners.

Support dates and lifecycle

vSphere releases follow a roughly seven-year lifecycle: about five years of general support from general availability, then about two years of technical guidance (advisory only, no patches). Authoritative dates are on the Broadcom product lifecycle page.

ESXi 7.0 passed end of general support in October 2025, which makes ESXi 8.0 U3 the floor for a supported host today and puts 7.x estates on a migration clock. Individual update releases within a version also carry their own patching windows — running 8.0 does not by itself mean a specific old build still receives fixes.

Hardware requirements

Minimums for ESXi 8.0, from the official ESXi requirements documentation:

• A supported 64-bit x86 server platform with at least two CPU cores
• Hardware virtualization (Intel VT-x or AMD RVI) enabled in firmware, and the NX/XD bit enabled
• 8 GB RAM minimum to install; more for any real VM workload
• A boot device of at least 32 GB persistent storage (HDD, SSD, or NVMe); SD cards and USB sticks are no longer suitable as sole boot media because of the ESX-OSData partition's endurance requirements
• One or more supported Gigabit or faster network adapters

The word supported carries weight: ESXi ships drivers only for certified hardware. Before buying or repurposing a server, check the exact model, CPU generation, NICs, and storage controllers against the Broadcom Compatibility Guide. Consumer desktop NICs (common Realtek chips, for example) have no inbox driver and are the most frequent cause of failed installs on non-certified hardware.

Installing ESXi: the short version

1. Confirm the server and its components in the Compatibility Guide, enable VT-x/AMD-V and NX/XD in firmware.
2. Download the ESXi ISO from the Broadcom Support Portal and write it to a USB installer or mount it via out-of-band management (iDRAC, iLO, IPMI).
3. Boot the installer, select the boot disk (minimum 32 GB), set the root password, and let it complete — the interactive install takes a few minutes.
4. On first boot, set a static management IP, hostname, and DNS in the Direct Console UI (DCUI).
5. Open the Host Client in a browser at the management IP, apply a license (free 8.0 U3e key or subscription), create a datastore, and build VMs. Add the host to vCenter if it will join a cluster.

Production deployments add more: NTP, syslog forwarding, lockdown mode, separate vSwitches or distributed switches for management, vMotion, and VM traffic, and a patching baseline through vSphere Lifecycle Manager. Design work at that layer is what our virtualization infrastructure support engagements cover.

FAQ

Is VMware ESXi free?

Partially. The free tier was withdrawn in February 2024, then ESXi 8.0 Update 3e was re-released with a free hypervisor edition in April 2025 (Broadcom KB 399823). The free edition is standalone only — no vCenter management, no support, no backup APIs. ESX 9 has no free edition.

What is the difference between ESXi and vSphere?

ESXi is the hypervisor installed on each host. vSphere is the product suite that bundles ESXi with vCenter Server and the cluster feature set. You install ESXi; you license vSphere.

Is ESXi being renamed?

Yes. Starting with version 9.0 (GA June 17, 2025), Broadcom renamed the hypervisor from ESXi back to ESX. The 8.x line keeps the ESXi name.

How long is an ESXi version supported?

About seven years: roughly five years of general support from GA plus two years of technical guidance. ESXi 8.0 reaches end of general support on October 11, 2027; ESXi 7.0 already reached it in October 2025.