Questions worth answering before you start.
Including the limits, and the ones where the answer is no.
Which protocols are supported?
HTTP, WebSocket and TCP. HTTP and WebSocket endpoints get a subdomain; TCP gets a dedicated relay port. The free plan covers HTTP; WebSocket and TCP are part of the paid plans.
Can I try it without creating an account?
Yes. The webhook inspector at /webhook-inspector provisions a temporary public URL immediately, with no account and no card: 1,000 requests per month, 50 stored requests, and a 24-hour TTL. Register to unlock Endpoints. Walkthroughs live under /blog.
What does the free plan include?
After registering: one HTTP endpoint of your own, 10,000 requests per month, 100 stored requests, 5 request rewrites and 8 concurrent sessions. Each of those is enforced in code, and when a monthly limit is reached the relay answers 429 rather than dropping traffic quietly.
Can I pay for a plan today?
Yes. Open /pricing to compare Free, Solo, and Team with country-localized Paddle prices. Checkout happens in the console under Settings → Plan & usage (sign in first). Solo includes a one-time 7-day trial with a card on file; the free plan stays available without paying.
What is remote MCP, and which plans include it?
Remote MCP lets an MCP client (Cursor, Claude Desktop, and others) inspect HTTP request history for this workspace’s tunnels via /api/mcp and a Bearer API key. Included with Solo and Team — Free shows an upgrade path in Workspace Settings → API keys. Setup: /mcp and the MCP guide under /blog.
Which platforms can run the agent?
The macOS desktop app runs the agent for all three protocols, as a DMG for Apple Silicon and Intel. The npm CLI (@mercur_dev/cli) does the same on macOS, Linux, and Windows with Node.js 20+. The browser console can receive HTTP traffic in Logging mode without installing anything.
How is access controlled?
Console routes require an authenticated session, the agent authenticates with a token you can rotate, and any endpoint can be marked private with an IP or CIDR allow list.
Where are request logs stored, and for how long?
On Mercur infrastructure, not on your machine, for 30 days. Bodies are truncated to a 256 KB preview and headers to 32 KB. An endpoint only records logs in Logging mode, or in Tunneling when full traffic capture is enabled.
What happens when my agent disconnects?
The endpoint stops serving within about 15 seconds and returns 503 until the agent reconnects. Requests that arrive during that window are not queued or replayed.
Can I replay a stored request?
Yes. In the console request history, Retry re-sends a stored HTTP request through the endpoint so you can re-test after fixing a handler. The endpoint must be in proxy mode with the agent connected. Replay respects plan retention and stored-request limits; payloads omitted for size cannot be replayed.
Keep going
Compare plans, open the blog, or start without an account.