MCP Gateway Comparison: ACP vs Composio vs Self-Hosted
You have MCP servers. They expose tools to your LLM. They work in development.
Now you need to put them in production. And you’re staring at a gap between “this works on my laptop” and “this is ready for real users.” The gap is identity, access control, audit logging, rate limiting, PII detection, and multi-tenant isolation. The gap is governance.
An MCP gateway sits in that gap. It intercepts tool calls between MCP clients and MCP servers and applies the controls you need before the call reaches your backend. The question isn’t whether you need one — it’s which one fits your situation.
There are three real options: build it yourself with open-source MCP servers, use Composio’s managed integration platform, or use ACP (Agentic Control Plane) as a governance layer. Each one is a legitimate choice depending on what you’re optimizing for.
Here’s an honest breakdown.
Option 1: Self-Hosted (DIY)
The open-source MCP ecosystem is large. There are thousands of MCP servers on GitHub covering everything from databases to CRMs to file systems. You pick the ones you need, deploy them on your own infrastructure, and wire them into your agent framework.
What you get: Full control. You own the code, the deployment, the data flow. You can modify any server to fit your exact requirements. There’s no vendor dependency and no usage fees.
What you build yourself: Everything else.
A raw MCP server has no concept of user identity. It doesn’t know who’s calling it. It has no access control — every caller gets the same capabilities. There’s no audit trail beyond whatever logging you add. There are no rate limits unless you implement them. No PII detection. No multi-tenant isolation.
If you have the security engineering capacity to build and maintain these layers, self-hosting is a strong option. You’ll spend time on infrastructure instead of product, but you’ll end up with exactly the system you want.
The realistic timeline is days to weeks for a basic governance layer, longer for production-grade implementations. You’ll need to handle JWT validation, policy enforcement, content scanning, structured logging, and per-user rate limiting across every MCP server you deploy. That’s not boilerplate — it’s a real engineering investment.
Honest assessment: Self-hosting is underrated for teams that genuinely need maximum control and have the expertise to do it well. It’s overrated by teams who underestimate the ongoing maintenance cost of a custom governance layer. The initial build is the easy part. Keeping it secure, auditable, and compliant across 10+ MCP servers as your agent fleet grows — that’s where it gets expensive.
Option 2: Composio
Composio is a developer-first integration platform. Their pitch is simple: they give you 850+ pre-built integrations with a clean SDK, and you can connect your agent to Slack, GitHub, Salesforce, Google Workspace, and hundreds more in minutes.
What they do well:
The developer experience is genuinely good. You install the SDK, authenticate with OAuth, and your agent has working integrations immediately. For someone building a prototype or an internal tool, the time-to-working-demo is hard to beat. Minutes, not hours.
The integration breadth is real. 850+ is a large catalog. If your primary concern is “I need my agent to talk to a lot of services,” Composio has probably already built the connector.
Their SDK ecosystem supports multiple agent frameworks — LangChain, CrewAI, Autogen, and others. If you’re using one of these frameworks, Composio integrates cleanly.
Where it’s less strong:
Composio is focused on the connection problem: getting your agent talking to external services. It’s less focused on the governance problem: controlling who can use those connections, what data flows through them, and maintaining a compliance-grade audit trail.
Identity verification is API-key-based rather than JWT-with-identity-provider. Multi-tenant isolation — where different users of your platform get different permissions on the same agent — isn’t the core use case. If you’re building a platform where 500 users each interact with agents that access sensitive data, and each user needs distinct access controls with identity-verified audit trails, you’ll need to build that layer on top.
It’s also not open source, and there’s no self-host option. Your tool calls route through Composio’s infrastructure. For many use cases, that’s fine. For regulated industries or data sovereignty requirements, it may be a blocker.
Honest assessment: Composio is the fastest path from “I want my agent to use Slack” to “my agent uses Slack.” They’ve invested heavily in integration breadth and developer experience, and it shows. If you’re evaluating MCP gateways primarily for integration speed and coverage, Composio is strong. If you’re evaluating primarily for identity governance and compliance, it’s not their focus.
Option 3: ACP (Agentic Control Plane)
ACP approaches the problem from the opposite end. Instead of starting with integrations and adding governance, it starts with governance and adds integrations.
The core is GatewayStack, an open-source (MIT) framework with modular governance components:
- identifiabl — JWT verification against Auth0, Okta, Entra ID, Firebase, or any OIDC provider. Every tool call is bound to a verified user identity.
- transformabl — PII detection and redaction. Scans tool inputs and outputs for sensitive data before it reaches your backend or returns to the model.
- explicabl — Structured audit logging. Every tool call is logged with the verified user identity, the policy decision, the tool called, and the outcome.
- limitabl — Per-user, per-agent rate limiting and budget caps. Prevents runaway agent loops and controls cost per user.
- proxyabl — SSRF protection. Prevents tool calls from accessing internal network resources they shouldn’t reach.
There’s also ACP Cloud — a managed version at cloud.agenticcontrolplane.com — if you don’t want to run the infrastructure yourself.
What it does well:
The governance layer is comprehensive. Identity flows through every tool call. Audit trails are structured and attributable to individual users. PII detection works at the request level, not as an afterthought. Rate limiting is per-user and per-agent, not just platform-level.
Multi-tenant isolation is a first-class feature. If you’re building a platform where multiple customers or teams use agents that access shared infrastructure, ACP handles tenant boundaries natively.
It’s open source. You can read the code, modify it, self-host it, or use the managed cloud. No lock-in.
Where it’s less strong:
The integration catalog is smaller. 25+ built-in connectors compared to Composio’s 850+. If your first question is “do you support [specific SaaS tool],” the answer is more likely to be “you can connect a custom MCP server for that” rather than “yes, it’s pre-built.”
The focus on governance means the setup involves decisions about identity providers, policy configuration, and audit destinations that Composio abstracts away. This is intentional — these decisions matter for production — but it means the time-to-first-demo is longer than a “install SDK, connect, go” experience.
Honest assessment: ACP is purpose-built for teams that need to answer “who accessed what, with what permissions, and is there a record?” If your deployment involves sensitive data, compliance requirements, multi-tenant isolation, or enterprise customers who will ask about your governance posture, ACP addresses those requirements directly. If you need 850 integrations and governance isn’t the primary concern, it’s more infrastructure than you need.
Comparison table
| Feature | Self-Hosted | Composio | ACP |
|---|---|---|---|
| Integration count | Varies | 850+ | 25+ built-in + custom |
| Identity verification | DIY | API keys | JWT + multi-IdP (Auth0, Okta, Entra, Firebase) |
| PII detection | No | No | Built-in (transformabl) |
| Audit trail | DIY | Basic | Full structured logging (explicabl) |
| Rate limiting | DIY | Platform-level | Per-user, per-agent (limitabl) |
| Open source | Depends | No | Yes (MIT, GatewayStack) |
| Self-host option | Yes | No | Yes |
| Multi-tenant | DIY | No | Yes |
| Agent-to-agent governance | No | No | Yes |
| MCP endpoint | Yes | Yes | Yes |
| SSRF protection | DIY | Unknown | Built-in (proxyabl) |
| Setup time | Hours/days | Minutes | Minutes |
Every “DIY” in the self-hosted column represents real engineering work. Some teams have the capacity for that. Most don’t.
When to use each
Self-Hosted is the right choice when you need maximum control and have the security engineering expertise to build and maintain a governance layer. You own the full stack, and you’re willing to invest in custom infrastructure. This works well for internal tools where you control both the agents and the backends, your team is comfortable with security primitives, and you don’t need to demonstrate compliance to external auditors.
Composio is the right choice when developer experience and integration speed are your priorities. You want working agent integrations in minutes, not days. You’re building prototypes, MVPs, hackathon projects, or internal developer tools where the primary goal is “make the agent do useful things quickly.” If governance requirements emerge later, you can address them then. For the current stage, velocity matters more.
ACP is the right choice when governance is a requirement, not a nice-to-have. You’re deploying agents that access sensitive data. You have compliance requirements (SOC 2, HIPAA, ISO 27001). You’re building a multi-tenant platform where different users need different permissions. Enterprise customers are asking about your AI governance posture. Or you simply want identity-verified audit trails from day one because you’ve learned the hard way that retrofitting governance is painful.
The governance gap
Here’s the thing most MCP gateway comparisons miss: most solutions solve the connect problem. How do I get my agent talking to Slack, to my database, to my CRM? That’s important. But it’s table stakes.
The harder problem is govern. Who is making this tool call? Are they allowed to? Is sensitive data flowing through the request? Is there a record? Can I prove to an auditor that access controls were enforced?
This is the gap that shows up in enterprise deployments. The agent works. The integrations work. Then security review asks: “Show me the audit trail for this user’s agent activity last Tuesday.” And the answer is either a clean, structured log with identity attribution — or it’s grep through CloudWatch hoping the timestamps line up.
Identity, audit, PII detection, per-user rate limits — these aren’t features you add to check a box. They’re the difference between a demo and a deployment. Most MCP gateway options address the connect side thoroughly. Fewer address the govern side.
Can you combine them?
Yes. These options aren’t mutually exclusive.
ACP can sit in front of self-hosted MCP servers as a governance proxy. You deploy whatever open-source MCP servers you want, and ACP handles identity verification, policy enforcement, PII detection, rate limiting, and audit logging for all of them. The MCP servers don’t need to change — ACP operates at the boundary.
You can also use Composio’s integrations and route them through ACP for governance. Composio handles the connection to 850+ services. ACP handles the governance layer: verifying who’s making each call, enforcing per-user policies, scanning for PII, and producing audit trails. You get breadth from Composio and governance from ACP.
This is the same pattern that works elsewhere in infrastructure. Your CDN doesn’t replace your firewall. Your API gateway doesn’t replace your IAM provider. Different tools handle different layers of the problem. The connect layer and the govern layer can come from different vendors and work together.
Making the decision
There is no single best MCP gateway. There’s the best one for your situation.
If your priority is integration breadth — getting your agent connected to the maximum number of services with the least effort — Composio is the strongest option. They’ve invested heavily in this and it shows.
If your priority is full control — owning every component, modifying anything you want, no vendor dependency — self-hosted is the right path. Bring your security engineering capacity.
If your priority is governance and compliance — identity-verified access control, PII detection, structured audit trails, multi-tenant isolation, per-user rate limits — ACP addresses these requirements directly, either as open-source GatewayStack or as a managed cloud service.
Most teams eventually need all three capabilities. The question is which one you need first, and which ones you can add later. Start with your most pressing constraint and build from there.
ACP Cloud free tier: 5,000 calls/month, 5 connectors, unlimited seats. No credit card required.
Try ACP Cloud free -> · GatewayStack on GitHub -> · Reference architecture ->