# Fettle

> Fettle is uptime monitoring for developers. It checks HTTP endpoints, TCP ports, DNS records, SSL certificates, ping targets and cron heartbeats from up to three regions (the USA, Europe and Asia; one on Free), opens an incident when a check fails, notifies over email and Telegram on every plan plus Slack, Discord or webhooks on paid plans, and publishes a status page.

- Free tier with no credit card; paid plans start at $9/month, or $90 a year ($7.50/month).
- Public REST API on every plan, authenticated with an API key as a Bearer token.
- MCP support in two channels: a hosted endpoint and an npm package for stdio clients.
- Status pages and incident acknowledgement on every plan; renotification from Plus; maintenance windows from Pro.
- Free tools with no sign-up: an uptime/SLA calculator, an SSL checker and a multi-region check.

## Docs
- [Documentation](https://fettle.sh/docs): Fettle's public REST API and MCP integration: what they cover, how to authenticate with an API key, and which page to read first.
- [Quickstart](https://fettle.sh/docs/quickstart): From no account to a monitor checking your site in three API calls: create an API key, list your monitors, then create an HTTP one.
- [API keys](https://fettle.sh/docs/api-keys): How Fettle API keys work: read and write scopes, expiry and rotation, IP allow-lists, and the per-plan request limits every key shares.
- [MCP](https://fettle.sh/docs/mcp): Set up the Fettle MCP server in Claude, Codex, Cursor or Windsurf: the hosted endpoint or the fettle-mcp npm package, with one API key.

## Plans
- Free: free forever, no card — 20 monitors, checks as often as every 3 min, 1 region, 7 days of history.
- Plus: $9/month, or $90 a year ($7.50/month) — 50 monitors, checks as often as every 1 min, 2 regions, 90 days of history.
- Pro: $19/month, or $190 a year ($15.83/month) — 100 monitors, checks as often as every 1 min, 3 regions, 180 days of history.
- Max: $39/month, or $390 a year ($32.50/month) — 300 monitors, checks as often as every 30 sec (50 monitors below 1 min), 3 regions, 1 year of history.
- Enterprise: custom pricing — Custom limits, all regions, SSO, and priority support. Contact support@fettle.sh.

## Product
- [Home](https://fettle.sh/): What Fettle monitors and how alerting works.
- [Pricing](https://fettle.sh/pricing): Plan ladder, limits and what each tier includes.
- [API](https://fettle.sh/api): The public REST API: what it covers, how keys work, two example requests.
- [MCP server](https://fettle.sh/mcp): The MCP server for Claude, Codex and any MCP client: tools and setup.
- [Free tools](https://fettle.sh/tools): Uptime/SLA calculator, SSL checker, multi-region check.
- [Uptime / SLA calculator](https://fettle.sh/tools/uptime-calculator): Convert an availability target into the downtime it actually allows — per day, week, month and year. 99.9% is 43 minutes a month.
- [SSL certificate checker](https://fettle.sh/tools/ssl-checker): Check any domain's SSL certificate for free: issuer, validity window, days until expiry and the full chain, with no sign-up and nothing to install.
- [Multi-region website check](https://fettle.sh/tools/multi-region-check): Check any URL's status, HTTP status code and response time from the USA, Europe and Asia at once. Free, with no sign-up and nothing to install.
- [Use cases](https://fettle.sh/use-cases): Setup guides for common platforms, cron jobs and SSL.
- [Comparisons](https://fettle.sh/vs): Fettle next to other uptime monitoring tools, figure by figure.
- [Blog](https://fettle.sh/blog): Round-ups and buying notes for developers.
- [About](https://fettle.sh/about): Who runs Fettle, where its checks run, and how to reach support.

## Comparisons
- [Fettle vs Pingdom](https://fettle.sh/vs/pingdom): Pingdom sells uptime checks in bundles, not per-monitor tiers. Here is what 50 monitors cost on each, and where each one is the better fit.
- [Fettle vs UptimeRobot](https://fettle.sh/vs/uptimerobot): UptimeRobot prices by monitor count across four plans, Free through Scale. Here is how the two ladders compare on density, regions, and history.
- [Fettle vs Better Stack](https://fettle.sh/vs/better-stack): Better Stack prices per responder licence and bundles logs, traces and on-call into one product. Here is how the two ladders and check models compare.
- [Fettle vs StatusCake](https://fettle.sh/vs/statuscake): StatusCake bundles page-speed, domain and SSL monitors into one plan; Fettle checks every region before an incident opens. Here is the trade-off.
- [Fettle vs Hyperping](https://fettle.sh/vs/hyperping): Hyperping beats us on price at 30-second checks. Here is that trade, plus where our fan-out check model and REST API pull ahead.

## Alternatives
- [The best UptimeRobot alternatives for uptime monitoring](https://fettle.sh/alternatives/uptimerobot): UptimeRobot alternatives for uptime monitoring, compared on price, check interval, check model, heartbeats and API, with a source for every figure.
- [The best Better Stack alternatives for uptime monitoring](https://fettle.sh/alternatives/better-stack): Better Stack alternatives for uptime monitoring, compared on price for 50 monitors, check interval, check model, heartbeats and status pages, all sourced.

## Use cases
- [How to monitor your Vercel app](https://fettle.sh/use-cases/monitor-vercel-app): Vercel tells you about builds and functions, not whether your site answers. Here is what to monitor and how to set it up in minutes.
- [How to monitor your Railway app](https://fettle.sh/use-cases/monitor-railway-app): Railway's healthcheck only runs during a deploy, not after. Here is what that leaves uncovered on a long-lived container and how to monitor it in Fettle.
- [How to monitor your Fly app](https://fettle.sh/use-cases/monitor-fly-app): Fly's health checks decide routing per region, not whether your app is up everywhere. Here is what to monitor across regions and how to set it up.
- [How to monitor your Supabase project](https://fettle.sh/use-cases/monitor-supabase-project): A Supabase project is REST, Auth, Storage and Realtime under one ref, not one service. Here is what to check separately and how to set it up.
- [How to monitor a cron job with a heartbeat](https://fettle.sh/use-cases/cron-job-monitoring): A cron job that stops running fails no request and throws no error. Here is how a heartbeat catches the silence before you do.
- [How to catch SSL certificate expiry before it hurts](https://fettle.sh/use-cases/ssl-expiry-monitoring): Renewal is automated and mostly works, which is exactly why nobody notices when it quietly stops. Here is what to monitor and how to get warned early.

## Blog
- [Best uptime monitoring tools for developers (2026)](https://fettle.sh/blog/best-uptime-monitoring-tools-developers): Twelve uptime monitoring tools, from Uptime Kuma to Datadog, one category each. Every figure links to the vendor's own pricing page, docs or README.

## Machine-readable
- [OpenAPI JSON](https://api.fettle.sh/public-api/openapi.json): every endpoint an API key may call, as an OpenAPI document.
- [API reference](https://api.fettle.sh/public-api/docs): the same endpoints as a browsable HTML page.
- [MCP tool contract](https://api.fettle.sh/public-api/mcp-tools.json): the tools both MCP channels expose.
- [Full brief](https://fettle.sh/llms-full.txt): this document, expanded, with examples.

## Code
- [GitHub: fettlesh/monitoring-mcp](https://github.com/fettlesh/monitoring-mcp): source of the open-source `fettle-mcp` MCP server.
- [npm: fettle-mcp](https://www.npmjs.com/package/fettle-mcp): the package `npx -y fettle-mcp` runs.
- [MCP Registry: sh.fettle/mcp](https://registry.modelcontextprotocol.io/v0.1/servers/sh.fettle%2Fmcp/versions/latest): the official registry entry, both channels.

## Optional
- [Terms of Service](https://fettle.sh/terms): Accounts, plans and billing, refunds, acceptable use.
- [Privacy Policy](https://fettle.sh/privacy): What data Fettle collects, why, and your rights over it.