Compare the workflow, limits, and developer experience
One npx command gives you a public HTTPS URL that forwards to localhost with no account at all. From there the same product grows into a workspace: stable endpoints, request history, a read-only share link, IDE agents over MCP, and a temporary inbox for inbound email. Use this page to see how that compares with the tools developers reach for when Stripe, GitHub, or Shopify need a public URL.
Mercur vs the tools you already know
Short phrases for the jobs that matter when debugging webhooks locally — not an empty checklist.
| Feature | Mercur | ngrok | Hookdeck | webhook.site | Hooklistener | Cloudflare Tunnel |
|---|---|---|---|---|---|---|
| Public URL without signup | 24h URL, no account — browser inspect or CLI tunnel | Account required | Console / CLI entry | Instant URL, no account | No-signup URL (vendor-documented) | Cloudflare account required |
| Forward to localhost without signup | npx CLI, no account or token | CLI after signup and authtoken | CLI with a console login flow | whcli forward; no api key needed on free | Optional CLI tunnel (vendor-documented) | cloudflared plus a Cloudflare account |
| Persistent URL (free) | Free: 1 HTTP endpoint with a stable URL | Free plan includes one auto-assigned dev domain | Stable sources | Permanent URLs typically paid | Account unlocks persistent URLs (vendor-documented) | With your domain |
| Built-in webhook inspection | Console history + body preview | Traffic Inspector | Event history | Browser inspect | History + live explorer (vendor-documented) | Not a webhook console |
| Request replay | Manual retry from console | Traffic Inspector replay (full capture) | First-class replay | CLI can re-forward captured requests | Replay (vendor-documented) | Not a webhook replay product |
| HTTP / WebSocket / TCP | HTTP on Free; WS/TCP on paid | Broad protocol coverage | HTTP webhooks | HTTP | HTTP webhooks (vendor-documented) | Network tunnel (HTTP and more) |
| IDE / agent inspect (MCP) | Hosted Remote MCP over OAuth (Solo / Team) | MCP gateway for your own servers | CLI MCP (hookdeck gateway mcp) | No first-party webhook-inspect MCP documented | Vendor marketing mentions MCP editor integration | No first-party webhook-inspect MCP documented |
| Inbound email testing | Temporary @mercur-mail.com inbox (Solo / Team) | Tunnel product, no inbound mailbox documented | Email through a provider webhook (Mailgun, SendGrid) | Email address per token (…@emailhook.site) | Positioned around webhook URLs (vendor-documented) | Tunnel routes HTTP and TCP; Email Routing is separate |
| Read-only link for someone else | 24h share link, revocable | Traffic Inspector sits behind the account | Event history sits behind the account | URL id is the link — anyone who has it can read | Team workspaces (vendor-documented) | Access is policy-based, not a log link |
| Team sharing | Team plan seats | Paid plans | Teams | Paid team features | Team workspaces (vendor-documented) | Via Zero Trust |
Last verified: 3 September 2026. A guest Mercur tunnel needs no account: the npm CLI forwards to localhost, while the browser inspector URL only records and answers 204. Guest sessions idle out after 24 hours. WebSocket, TCP, Remote MCP, and temporary mailboxes are Solo and Team. Competitor details change — verify on each vendor’s site.
Pick a comparison
Mercur vs ngrok
Mature localhost tunnel with a CLI, Traffic Inspector, replay, and an auto-assigned free-plan domain.
Read comparison →Mercur vs Hookdeck
Webhook event gateway with ingest, filtering, replay, and CLI MCP — oriented beyond local debug.
Read comparison →Mercur vs webhook.site
Instant payload bin with browser inspect and an email address per token. CLI forward (`whcli`) when you need localhost.
Read comparison →Mercur vs Hooklistener
Webhook URL + inspect product aimed at no-CLI, no-signup debugging (vendor-documented).
Read comparison →Mercur vs Cloudflare Tunnel
Mature edge tunnel with your Cloudflare account and domain — not a webhook console.
Read comparison →See traffic as it lands
Every Endpoint keeps a request log — method, path, status, timing — so you can tell a bad payload from a handler that never ran.
Live payload explorer
Watch deliveries land with method, path, status, headers, and body preview. Retry a request from the console after you fix the handler.
- Syntax-highlighted JSON body preview
- Headers + timing on every request
- Manual retry when you are ready to re-test
Questions people ask before switching
Which of these tools tunnel to localhost without an account?
Mercur and webhook.site both can. `npx @mercur_dev/cli http 3000` opens a guest Mercur tunnel with no account and no token, and webhook.site’s whcli forward works without an API key on free tokens. ngrok wants a signup and an authtoken first, and Cloudflare Tunnel needs a Cloudflare account plus cloudflared.
What does a free Mercur tunnel include?
A guest HTTP tunnel gives you a public HTTPS URL that forwards to a local port, a request log with headers and body preview, and a share link. Guest sessions carry 1,000 HTTP requests per month, keep the 50 most recent requests, and idle out 24 hours after you stop. WebSocket and TCP need Solo or Team.
Is Mercur a free ngrok alternative?
For the webhook and localhost-debugging job, it covers the same ground and starts without a signup. ngrok is the broader network tool — more protocols, more platforms, Traffic Inspector with replay, and an auto-assigned dev domain on its own free plan. Mercur does not try to replace it as general infrastructure.
Do I have to install anything to see a payload?
No. The guest webhook inspector is a browser URL: it records what arrived and answers 204, so nothing reaches your machine. Install the npm CLI (Node.js 20+) or the macOS app when you want that traffic forwarded to a local port.
What changes when I create a free account?
You get one HTTP endpoint with a stable URL, 10,000 requests per month, and a console that keeps the last 100 requests per endpoint for three days. Registering from the guest inspector moves that guest URL and its stored requests into your new workspace, so senders keep working.
Start with a public webhook URL
Inspect in the browser, or run npx @mercur_dev/cli http 3000 to forward the same traffic to localhost without an account. Paste the URL into Stripe, GitHub, or Shopify.