MCP Gateway Build vs. Buy

TL;DR

• Buy an MCP Gateway when more than one team shares infrastructure or compliance requires audit trails.
• Build an MCP Gateway when MCP usage scale is still low, under five MCP servers.
• The real question is governance speed, not engineering cost.
• Credentials are the biggest risk either way: over half of MCP servers still use static API keys.
• MCPX Enterprise is the strongest buy option for MCP at scale.

What does "build vs. buy" mean for an MCP gateway

Build means standing up your own aggregation layer. You write a service that authenticates users, routes requests to MCP servers, and logs what happened. Buy means adopting a vendor's gateway that already does this, self-hosted or managed.

MCP itself is open and free either way. What you're really deciding is who owns the governance layer on top: identity, permissions, and audit trails. Most build-vs-buy advice gets this wrong. It measures engineering hours, a one-time cost. Governance debt compounds every time you add an agent or tool without updating the control layer.

What is an MCP Gateway

An MCP gateway sits between your agents and every MCP server they call. It enforces authentication, access control, and audit logging. The Model Context Protocol (MCP) is the open standard, introduced by Anthropic in late 2024, for letting AI agents call external tools through a common interface. MCPX is Lunar.dev's MCP Gateway, one of the first and well-known gateways in the category.

Build Vs. Buy at a glance

Why the build option always looks cheaper than it is

A gateway prototype is easy to build. A small team can stand one up in a few weeks. What's hard is everything that comes after, since the tool list and the protocol both keep changing.

Credentials are the biggest blind spot. Astrix Security's 2025 research found 88% of MCP servers require credentials, and 53% still use static API keys instead of short-lived tokens. That's the OWASP MCP Top 10's leading risk (via Nordic APIs). A homegrown gateway built on static keys is cheap now and expensive once compliance asks how credentials rotate.

ROI calculation: build vs. buy MCP gateway

The pattern is familiar: one AI tool gets rolled out and governed carefully, then more follow, and soon agents are reaching into Jira, GitHub, and internal databases through connections nobody approved.

Three costs show up once the prototype works:

• Ongoing maintenance

MCP is still a moving protocol, and every server your agents call carries its own credential rotation cadence. Lunar's own research on this puts it plainly: "Rotating credentials across thousands of instances means tracking down every place a secret was used. At scale, this becomes a fire drill with no guaranteed end state." Most teams don't keep up: Astrix Security's 2025 analysis of 5,200+ open-source MCP servers found 53% rely on static API keys or personal access tokens that are rarely rotated, with 79% of those keys passed as plain environment variables, exactly the gap OWASP's MCP Top 10 names as its first risk category. A vendor absorbs that upkeep. Self-hosting means it's your team's job.

• Protocol drift

A breaking MCP spec change means internal triage across every connected server, patching client and server implementations, and re-testing agent workflows against the new behavior. That's not hypothetical: MCP's lead maintainers themselves shipped a release with the caveat "this release contains breaking changes, we don't intend for that to be the norm," and the spec versions each revision by the date of its last backward-incompatible change. Breaking changes are the norm the maintainers themselves are actively pushing against. ThingsBoard, a real open-source IoT platform running in production, is living that cost right now: its MCP connector is broken because Claude Desktop negotiates a newer protocol version than the server speaks, "Claude Desktop refuses to invoke any tools." A bought gateway ships each of those changes as a versioned release. Your team reads the changelog rather than the spec.

• No SLA and no vendor coverage

A homegrown gateway has no support commitment. When an agent breaks before a demo, there's no one to call but your own team. Lunar's Enterprise tier includes "Around-the-clock enterprise support and SLA-driven response times."

The cost of building your own MCP gateway

Most teams model the build cost as a sprint. The real cost compounds annually.

Rolled up: standing up a comparable gateway in-house runs $16,000 to $32,000 up front, at 4 to 8 weeks of a senior engineer's time and a $200k loaded rate, plus $6,000 to $13,000 a year afterward to keep it running. None of it is one-time. The bill resets every year the gateway stays homegrown.

The budget line item nobody planned for

Most companies never budgeted for "MCP gateway" as its own line item. It's usually folded into broad AI spend. That gap widens the moment teams realize an MCP gateway is only one piece of the agent stack they now need to govern.

An MCP gateway handles tool invocation. It does not handle LLM traffic, the skills catalog agents load at runtime, or the API calls agents make outside MCP. Companies that finish an MCP gateway project often find themselves standing up an LLM gateway not long after, then a skills catalog after that. Each brings its own governance, identity, and audit requirements. Getting all three to speak the same policy is what turns three separate projects into one governance program, and running them as parallel control planes is what most teams end up doing by default.

The strategic question is bigger than build or buy an MCP gateway. It is whether the platform you adopt covers the full agentic stack or forces you to solve identity, audit, and policy three separate times. Lunar.dev's platform pairs MCPX Enterprise with an AI Gateway for LLM traffic and an API Gateway for outbound calls, all sharing one policy, identity, and audit layer.

That unified footprint matters for compliance too. A single gateway governing MCP, LLM, and API traffic gives security review one artifact to evaluate instead of three separate reviews across products the company adopted at different times.

When building your own MCP Gateway is the right call

Build if your footprint is genuinely small and compliance exposure is low.

Signs you're a build candidate

• Fewer than five MCP servers, one team, one cluster.
• A static toolset, no plans to add teams or regions.
• No SOC 2, HIPAA, or ISO 27001 audit demanding centralized logs.
• Engineering willing to own credential rotation and auth code, permanently.

That threshold matches what Lunar co-founder Eyal Solomon found across real MCP deployments (Nordic APIs): single-cluster, single-team setups are fine to build. Ten-plus servers, multiple teams, or any compliance requirement tip toward buying. Past that line, a build works for the first few servers, then breaks once a second team wants in.

When buying an MCP gateway wins

Buy once more than one team needs shared infrastructure, or compliance starts asking questions your setup can't answer.

The first questions to surface: who approved this server, what can this agent touch, and can you produce an audit trail. Answering those takes a server catalog, identity-based access control, and logs that survive a review. That's real infrastructure, built once.

In-house build vs. MCPX, capability by capability

Whatever gateway you evaluate, this is the bar:

Most teams spend months building toward this table. A gateway could already be running in production instead.

How does MCPX increase AI adoption?

Employees default to personal AI accounts when company tools feel harder to use than the free alternatives. IDC's research on EMEA found only 23% of employees use the AI tools their company provides, and more than half rely on personal accounts instead. The credential risk from the earlier section is the same problem seen from the adoption side.

MCPX addresses this at the access layer. Employees and agents authenticate through the existing IdP, so no new credentials get created. When a token expires, MCPX exposes re-authentication as a tool the agent invokes inline, so non-technical users stay in their client instead of running a separate auth flow. Dynamic tool discovery surfaces newly approved servers as soon as they clear the catalog, and users see only the tools their role needs through role-based Profiles synced from the IdP.

Security still owns the approval and audit path. The user sees a shorter, working list instead of a wall of tools they have no permission to use.

See how this plays out in enabling AI adoption beyond engineering.

How does MCPX avoid vendor lock-in?

Self-hosting removes the two places buying usually creates lock-in. MCPX runs in your own Kubernetes or Docker environment. Configuration, traffic, and logs stay inside that boundary on every tier, not only the free one.

The MCPX core is also open source under MIT. If you ever leave Lunar, you still have a working gateway you already run yourself. MCP itself is an open protocol, so the servers and clients already wired up don't change either way.

AI Gateway and MCP Gateway deploy independently, so adopting MCPX doesn't require buying into the rest of the platform. A fully managed cloud gateway is a different trade. Your config and audit history live in the vendor's infrastructure, and leaving means rebuilding your catalog from scratch.

What to check before you commit, either way

Build vs. buy checklist

Score each item 0 to 2 for your situation. A higher total means buying is the safer path.

If you score high enough to buy, verify these against each vendor:

• Traffic stays in your environment, not a vendor edge
• Docs specify OSS versus Enterprise-gated features
• Desktop client honors a base-URL redirect
• Credentials are short-lived vault tokens
• Every claimed feature has a shipping date in the current docs
• Pricing starts with a free trial, scaling per seat

MCP is one piece of a bigger stack. LLM traffic and API calls need the same identity, policy, and audit controls, so a platform covering all three keeps governance from becoming three separate projects.

See Eyal Solomon's enterprise MCP adoption best practices on Nordic APIs, or explore Lunar's MCP gateway and book a demo.