How Much Does Custom MCP Integration Cost?

Why the range you'll find is so wide

Search this question and you'll find real numbers, but they span nearly two orders of magnitude, because "MCP integration" describes wildly different amounts of work. Independent cost breakdowns put a simple single-source connector (basic CRUD, one data source, minimal security requirements) at roughly 80–120 hours of build time, an API integration server with real auth and rate-limiting at 150–250 hours, and multi-system orchestration with enterprise permissions and compliance documentation at 400–800 hours. Enterprise-scale partner builds — SSO, RBAC, audit logging, a full security review — routinely run into six figures once you count the first year of maintenance, not just the initial build.

The recurring finding across independent write-ups: total first-year cost tends to run 2–3x the initial development estimate once security review, testing, and ongoing operational overhead get counted — sometimes higher for regulated industries like healthcare. The build is rarely the expensive part. The tax that comes after — patching, credential rotation, keeping pace with a spec that's still moving — is what the initial number tends to leave out.

The three things that actually move the price

• How many systems, not how many tools. Five tools against one internal API is a single-source build. One tool that has to reconcile data across three systems is a multi-source build — and the jump between those two tiers is usually bigger than it looks from the outside, because most of the real work is reconciliation and failure handling, not the tool count.
• Whether the upstream API is documented. A clean, documented REST API with existing SDKs is a predictable scope. An undocumented internal system means a discovery phase — reverse-engineering endpoints and response shapes from network traffic before the "real" build even starts. That's the single biggest source of scope creep in this category, and it's worth pricing as its own line item rather than hoping it doesn't happen.
• How seriously the auth layer is taken. An enterprise authentication layer — SSO integration, role-based access control, audit logging — commonly adds four to six weeks to a project on its own, independent of what came before it. Skipping this isn't actually cheaper; it just moves the cost to an incident later. (See the companion piece on auth-scoping patterns that hold for what that layer should actually contain.)

What we publish, flat, before any call

We think the "book a call for a quote" pattern is mostly there to hide the fact that the number depends on a scoping conversation the vendor doesn't want to have in public. Ours is a genuine scoping-gated ladder — the exact rung still depends on your one tool, its auth model, and whether the API is documented — but the rungs themselves are public, not gated behind a form:

That puts a single-source build at roughly the low end of the independent market range above, for the same shape of work — auth-scoped, fail-soft, tested, documented — plus a 14-day support window after handoff. If your situation is genuinely multi-system or undocumented-API territory, the audit is exactly the mechanism for finding that out before either of us commits to a number, and its cost rolls into whatever you build next.

How to budget before you talk to anyone

1. Count your systems, not your tools. One system, however many actions — single-source tier. More than one system that has to reconcile — multi-source tier.
2. Check if the upstream API is documented. If it isn't, budget for a discovery line-item on top of the base tier, not inside it.
3. Decide up front whether "done" includes the auth/audit layer. A build that skips scoped auth and structured logging isn't cheaper — it's the same cost, deferred to whenever the first incident forces it.
4. Get the cheap read before the expensive build. A fixed-price audit that credits toward the build removes the asymmetry where only the vendor knows the real scope going into a quote.