MCP Server Latency: What It Means and How to Compare Servers

MCP server latency is the time an MCP client waits for a successful response from a server endpoint. It directly affects the responsiveness of AI applications connecting to these servers. Wellknown measures latency only for network endpoints that respond successfully, reporting median and p95 latency to help developers understand typical and slower response times.

Key takeaways

• Latency for an MCP client is the response time of a successful check to a server endpoint.
• Wellknown reports median latency (p50) and p95 latency over a 7-day window for live endpoints.
• The median latency of daily medians is 126 ms, and the median p95 latency is 156 ms.
• Wellknown waits up to 8 seconds (probeTimeoutSeconds) for a server check before timing out.
• Local packages have no network latency because they run locally, so no latency is measured.
• Comparing servers on latency should be done alongside reliability data available on Wellknown's reliability page and API.

What latency means for an MCP client

Latency in the context of an MCP client is the duration between sending a request to an MCP server endpoint and receiving a successful response. This latency impacts how quickly an AI application can access tools, resources, or prompts exposed by the server. Lower latency means faster responses and better user experience.

Wellknown measures latency only for successful checks, meaning failed or timed-out requests are excluded from latency statistics. This ensures latency figures reflect actual response times when the server is reachable and responsive.

Observed latency figures in latencyMs

Wellknown aggregates latency measurements over a 7-day window, focusing on records with at least one successful check per day. The key latency metrics reported are:

• Median latency (p50): The middle response time of successful checks, where half the responses are faster and half are slower. The median of daily medians across records is 126 milliseconds.
• P95 latency: The response time that 95% of successful checks beat, representing the slower tail of response times. The median of daily p95 latencies is 156 milliseconds.

For a caller, the median latency indicates typical response speed, while the p95 latency shows how slow the server can be under less favorable conditions.

How long a check waits: probeTimeoutSeconds

Wellknown's product facts specify a probe timeout of 8 seconds. This means each check to an MCP server endpoint waits up to 8 seconds for a response before considering the check failed due to timeout. This timeout balances giving servers enough time to respond while not delaying failure detection excessively.

Why packages have no latency to measure

Local MCP servers installed as packages (for example, npm or PyPI packages) run on the client's machine. Because they do not communicate over a network endpoint, there is no network latency to measure. Wellknown marks such records with an observed status of "unknown" for latency because no network checks are performed.

This is the ordinary case for package endpoints, which are common in the MCP ecosystem.

How to compare MCP servers on latency with the reliability page and API

Latency alone does not give a complete picture of server performance. It should be considered alongside reliability, which measures the success rate of checks over time.

Wellknown provides a reliability page at https://wellknown.network/reliability where developers can compare servers by their observed success rates and latency metrics. The API at https://wellknown.network/api/v1 also exposes endpoints to query server status and latency data programmatically.

When comparing servers:

• Look for servers with low median and p95 latency values for responsiveness.
• Check the success rate to ensure the server is reliably available.
• Consider the endpoint type (remote HTTP vs. local package) since local packages have no network latency.

Combining latency and reliability data helps developers choose MCP servers that are both fast and dependable.

This data is a snapshot as of 2026-11-05T01:32:11.786Z.