Catch a payload — or debug the handler on localhost
webhook.site is the classic instant bin for raw requests. Mercur starts there with a guest URL, then unlocks Endpoints that forward to your laptop with full request history.
Choose Mercur when you need the payload and a path to run your real local handler (or pull history into an IDE agent).
Choose webhook.site when you only need to glance at a raw delivery as fast as possible with zero product lock-in.
Who wins which job
| Job | Mercur | webhook.site |
|---|---|---|
| Instant URL, no account | Yes — guest tester | Yes — category leader |
| Inspect in the browser | Yes | Yes |
| Forward to localhost | Endpoint + macOS agent | Not the free default path |
| Persistent free endpoint | Free registered HTTP tunnel | Permanent usually paid |
| Multi-protocol | HTTP / WS / TCP | HTTP |
| Remote MCP | Yes — Solo / Team | No |
Summaries as of August 2026. Verify current limits on each vendor’s pricing page.
Where Mercur is stronger
- Same zero-signup start, then a clear upgrade to localhost forward
- Stable Free HTTP tunnel after registration
- WebSocket and TCP on paid plans
- Remote MCP and team seats on higher plans
When webhook.site wins
- Maximum brand familiarity for “just show me the JSON”
- Broader automation / custom-action surface on paid tiers
- No agent install when all you need is a bin
Common questions
Is Mercur a webhook.site alternative?
Yes for catching and inspecting webhooks. Mercur also covers the next step — forwarding to localhost and debugging the real handler.
Does the guest URL forward to my laptop?
No. Guest mode is inspect-only. Register and connect the macOS agent to create a Endpoint that forwards to a local port.
How long does a guest URL last?
Guest endpoints are ephemeral with a 24-hour TTL and request caps documented on Pricing and FAQ.
Related pages
Mercur vs ngrok
The default localhost tunnel. Strong CLI; free URLs rotate; inspect is secondary.
Read comparison →Mercur vs Hookdeck
Webhook event gateway with strong ingest, filtering, and replay — oriented beyond local debug.
Read comparison →Mercur vs Hooklistener
Webhook URL + inspect product aimed at no-CLI, no-signup debugging.
Read comparison →Mercur vs Cloudflare Tunnel
Mature edge tunnel with your Cloudflare account/domain — weak webhook inspect UX.
Read comparison →Try Mercur on a real webhook
Get a public HTTPS URL, inspect the payload, then upgrade to a Endpoint when you are ready to hit localhost.