MCP Transport Statistics 2026: 89% of Servers Still Run on stdio

Local process transport still defines MCP: 463 of 520 directory listings use stdio, versus 47 on HTTP and 10 on legacy SSE.

Contents

• Methodology and limitations
• Main findings
• Interpretation
• Practical decision guidance
• How to cite and download the data
• Related MCPtrove research
• FAQ

Methodology and limitations

This analysis uses a snapshot of 520 directory listings in the MCPtrove directory. The unit of analysis is a listing, not an individual tool or end user. One listing can expose many tools, so transport share and tool share are different questions.

MCPtrove records transport, authentication, official-status, and tool-count information in normalized directory fields. These labels make listings comparable, but they do not necessarily reproduce every server’s own terminology or deployment architecture. In particular, the SSE field should be read as a directory distribution label, not proof that a listed service currently conforms to the latest protocol binding.

The figures describe this directory snapshot only. They do not estimate the total number of MCP servers in existence, measure traffic, report uptime, or show how users actually connect. MCPtrove did not survey users for this analysis. The results also do not establish that one transport causes a particular authentication pattern, tool count, or level of adoption.

The protocol context matters. The current Model Context Protocol transport specification identifies stdio and Streamable HTTP as the standard transport bindings. The official Streamable HTTP specification also explains that Streamable HTTP replaced the earlier HTTP+SSE approach and that legacy HTTP+SSE is deprecated. That makes the directory’s SSE category useful for understanding what is listed, but insufficient for deciding whether a server is current, maintained, or protocol-compliant today.

Main findings

The headline is straightforward: stdio is the directory’s dominant transport by a wide margin. HTTP and SSE together account for 57 of 520 listings (11.0%), which is meaningful enough to support a remote-services segment but not large enough to describe the directory as primarily remote.

HTTP listings expose more tools per listing on average than stdio listings: 16.3 versus 13.0. That is a descriptive difference, not evidence that HTTP produces broader integrations. A listing may represent a hosted product with a deliberately large surface area, while a local server may focus on one application or workflow.

Official-status counts also differ across labels. The directory contains 116 official stdio listings, 30 official HTTP listings, and 3 official SSE listings. These counts describe MCPtrove’s normalized official field. They should not be interpreted as a ranking of protocol quality, maintenance, security, or user satisfaction.

Authentication is the clearest sign that transport choice reflects deployment context. Stdio listings skew toward no authentication, with 229 no-auth listings compared with 206 API-key and 28 OAuth listings. HTTP has a different balance: 22 OAuth listings sit alongside 13 no-auth and 12 API-key listings. SSE remains too small a category for confident interpretation, with 3 no-auth, 4 API-key, and 3 OAuth listings.

Interpretation

“Remote is the future” is a direction of travel, not a migration instruction. The directory evidence supports a more useful conclusion: local process transport remains the rational default for many single-user tools, while Streamable HTTP earns its additional complexity when a service must be shared, hosted, or accessed by multiple clients.

Stdio has a strong practical advantage in local workflows. The client starts or connects to a process on the same machine, and the interaction model maps cleanly to personal development tools, desktop applications, local files, private repositories, and machine-specific utilities. A local server does not need to solve every problem associated with public networking, service discovery, remote authentication, or multi-tenant isolation.

Remote transport is valuable when those problems are the point of the product. A hosted data service, a team-wide internal platform, or a provider intended for several client environments may need a stable network endpoint and an explicit identity layer. In those cases, Streamable HTTP is not merely a fashionable alternative to stdio; it is an architectural fit.

The directory’s HTTP and SSE labels should therefore be read with care. HTTP is a broad directory category and may include listings whose implementation details differ. SSE is especially easy to overread because the current protocol documentation distinguishes Streamable HTTP from deprecated HTTP+SSE. A legacy label in the directory is evidence of how a listing was classified, not a guarantee about its present wire behavior.

The same caution applies to authentication. More OAuth-labelled HTTP listings do not prove that HTTP requires OAuth, nor that stdio is inherently secure because it often lacks authentication. Authentication requirements follow the threat model and deployment boundary. A local process launched by one user has different exposure than a hosted endpoint reachable by several clients.

Practical decision guidance

Choose stdio first when the server is for personal use, runs beside the client, accesses local resources, or is tightly coupled to one machine. It keeps setup compact and avoids introducing a network service where one is unnecessary.

Choose Streamable HTTP when the server is hosted, shared, independently deployed, or expected to serve multiple clients. The extra operational work can be justified when remote access, centralized credentials, or shared availability is part of the requirement.

Treat authentication as a separate decision. Do not select a transport solely because its directory listings appear more likely to use OAuth or API keys. First define who can access the service, where credentials live, what data the server can reach, and whether the endpoint is exposed beyond one user’s machine.

When evaluating a listing, inspect its capabilities rather than stopping at the transport label. One listing can expose many tools, and the average tool count is only a descriptive summary. Review the actual tool names, permissions, documentation, maintenance signals, and compatibility with the client you intend to use.

For client selection, start with MCPtrove’s Claude client directory or Cursor client directory. Then use the capabilities directory to find servers by what they can do. This workflow keeps the transport question in its proper place: important for deployment, but secondary to whether the server fits the job.

How to cite and download the data

The complete source file is available as the raw MCP transport statistics CSV. Download it when you need to reproduce the directory totals, inspect individual normalized fields, or combine transport information with another MCPtrove research asset.

Use the CSV as a snapshot, not as a timeless benchmark. Directory composition can change as listings are added, removed, reclassified, or updated. Preserve the access date and the page URL whenever you reuse a figure. The safest citation makes clear that the result comes from MCPtrove’s directory snapshot rather than from a census of MCP servers or a user survey.

MCPtrove. “MCP Transport Statistics 2026: 89% of Servers Still Run on stdio”. https://mcptrove.com/research/mcp-transport-statistics. Accessed September 19, 2026.

Related MCPtrove research

For the security and identity context behind these transport patterns, see MCP Authentication Statistics.

For a deeper look at how many tools listings expose, see MCP Tool Count Benchmark.

For a practical comparison of deployment trade-offs, read Local vs Remote MCP.

FAQ

Does this dataset show that most MCP servers are local?

It shows that stdio is used by most listings in this MCPtrove directory snapshot. It does not establish the transport distribution of every MCP server in existence, and it does not measure usage or traffic.

Is HTTP better than stdio?

Neither transport is universally better. Stdio is usually the simpler fit for a single-user local workflow. Streamable HTTP is more appropriate when a service must be hosted, shared, or reached by multiple clients.

Should I avoid SSE?

Treat SSE as a signal to inspect the listing carefully. The current protocol documentation distinguishes Streamable HTTP from deprecated HTTP+SSE, so the directory label should not be treated as proof of current protocol conformance.

Does OAuth make an HTTP server safer?

Not automatically. OAuth can support an appropriate identity and authorization model, but security depends on implementation, scopes, credential handling, network exposure, and the sensitivity of the resources behind the server.

Where should I start if I need an MCP server?

Start with the Claude client directory or Cursor client directory, then browse capabilities. Evaluate the server’s tools and deployment requirements together rather than choosing from the transport label alone.