Uptime monitoring that nags the right people.

Websites, APIs, office links and mail servers, and the certificates, domains and DNS under them. Checked from five places or a box in your network, and confirmed before anyone is paged.

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14 days of Pro to start, then free for 20 hosts. No card, nothing to install.

What breaks, and who covers it
What breaks	Uptime tools	Enterprise suites	hostnag
A host goes downwebsite, API, VPN, mail, gateway	Yes	Yes, with collectors and a contract	Yes
A certificate expiresdays-before thresholds, daily inside the last window	No	Yes, with collectors and a contract	Yes
A domain lapsesregistration expiry from RDAP	No	No	Yes
A certificate is swappedfingerprint changed, wrong host, chain not trusted	No	Yes, with collectors and a contract	Yes
A DNS record driftsexpected answer missing or changed	No	Yes, with collectors and a contract	Yes
An ISP link dropsthe public address from several locations, by ping or a TCP port, confirmed by a ping from an internal device	No	Yes, with collectors and a contract	Yesexternal and internal
Mail stops being deliveredMX, SPF, DKIM, DMARC and blocklists, at the expiry cadence of your plan	No	No	Yes
A scheduled job stops runningcron, backups, workers: a heartbeat that goes quiet	Yes	Yes, with collectors and a contract	Yes
Your nameservers or registrar changenameservers, registrar, DNSSEC, certificate issuer, DNS answers, redirect targets	No	No	Yes
A vendor you depend on has an incidenttheir status page read for an outage or degraded state, the incident named	No	Yes, with collectors and a contract	Yesread from their own status page

The columns are kinds of tool; no product is named. Covered, with collectors to install, a contract to sign and enterprise pricing.

Active06

Alarm: 01
Supervisory: 02
Trouble: 00
Normal: 03
Unlit: 00

View

Acme Retail

06Sample data

DownHTTP

Checkout API

api.acme.example/health

Down47 min

checked 1 min ago

Expiring soonCert

mail.example.com

11d left10 Oct 2026

checked 40 min ago

UpTCP

VPN gateway

vpn.office.example

31ms

checked 2 min ago

OKDomain

example.com

40d left08 Nov 2026

checked 9 h ago

UpDNS

MX example.com

example.com

18ms

checked 4 min ago

DegradedHTTP

Storefront

shop.acme.example

1840msslow for 22 min

checked 1 min ago

What others miss

Each one below is drawn by the same code that writes it for a customer.

A renewal that stalled

Cert

[Warning] Certificate renewal for shop.acme.example looks stuck

shop.acme.example's certificate should have renewed by now (17 days left of 90 days). Check the renewal job.

An uptime check sees a working site, and an expiry reminder says a date is coming. This says a certificate that renews itself should already have been replaced, and that the renewal job is where to look.

Certificate monitoring

Down, with what changed

HTTP

[Critical] https://api.acme.example/health is down

Down from 2 of 3 locations (US East, Frankfurt). Last error: connect_timeout.

Changed recently: DNS answer on API DNS, 28 Sept 2026, 21:35 UTC: 198.51.100.7 (was 203.0.113.4)
Also in trouble: Card payments: Degraded, Elevated API error rates

The alert names what changed on the same host in the 24 hours before it went down and which of your vendors is in trouble, so the first guess is a good one.

Alerting

A subdomain open to takeover

Hosts

[Critical] Subdomain takeover risk on promo.acme.example

promo.acme.example points at acme-promo.herokuapp.com, which no longer exists at Heroku. Anyone can claim that name and serve content on promo.acme.example. Remove the CNAME or reclaim the name.

The main site is fine. A forgotten name still points at a deleted Heroku app, and whoever creates that app again serves pages on your domain. A subdomain watch finds names like this from your own DNS and homepage, every day, and says when one is fixed.

Subdomain watch How takeover works

Assessments. A client review or an audit as one report: the checks, your notes and verdicts, run again for a before and after, printed, shared by link or exported.Tools and assessments

Check one of yours now

The same check a monitor runs, once, nothing saved. Ten every ten minutes per address.

Check

All tools

What gets watched

Every monitor type is on every plan.

Uptime monitoringHTTP, TCP and ping from up to 5 places, confirmed before anyone is pagedHTTP · TCP · Ping Certificate monitoringExpiry, a swapped chain, and a renewal that stalledCERT Domain monitoringRegistration expiry, registry holds, nameservers that answer and DNSSECDOMAIN DNS monitoringThe answers people and mail depend on, watched for driftDNS Mail health monitoringMX, SPF, DKIM, DMARC and 4 blocklistsMAIL Link monitoringAn office or ISP line watched from outside and from insideLINK Heartbeat monitoringA URL per scheduled job; when it goes quiet, you hearHEARTBEAT Vendor status monitoringYour vendors' incidents, read from their own status pagesVENDOR Alerting9 channels, escalation, quiet hours and maintenanceALERTS Status pagesA public page with uptime strips, incidents, a feed and badgesSTATUS PAGE BeaconsA plain script that runs the same checks from inside your networkBEACON Discovery and subdomain watchEvery name under a domain, the ones open to takeover, and a daily watchDISCOVER Tools and assessmentsOne-off checks, and client reviews as a report you can shareTOOLS

How you get nagged

What you get told

[Critical] https://www.example.com/ is down
Down from 2 of 3 locations (US East, Frankfurt). Last error: unexpected_status: 503.
HTTP
[Critical] api.example.com certificate expires in 2 days
The certificate for api.example.com expires in 2 days (14 Sept 2026). Renew it before then.
Cert
[Warning] DNS answer changed for api.example.com
The api.example.com record now answers 198.51.100.7 (was 203.0.113.10), from every location we checked.
DNS
[Recovered] https://www.example.com/ is back up after 1 h 15 min
https://www.example.com/ answered again from every location. It was down for 1 h 15 min.
HTTP

Sample alerts, rendered by the same code that writes your email and Slack messages.

Thresholds: 30, 14, 7, 3 and 1 days before an expiry, each once, then daily inside the last window.
Confirmation: A host is down only after 2 confirmations: a second location or a second consecutive run.
One episode: One notice when it opens, reminders at the interval you set, one when it clears.

Seen over time, in public

The rows your status page draws: a cell per hour, response time a click away, a runway for a certificate, a day of health for mail. Hover a cell. hostnag's own page

Monitors

Last 24 hours, UTC

Up
Blip
Down
No runs

Healthy
Needs attention
At risk
Not checked

StorefrontUp
99.98%
00:0006:0012:0018:00
CheckoutUp
99.91%
00:0006:0012:0018:00

Behind the scenes

3 monitors

Card payments (vendor)Up
99.72%
00:0006:0012:0018:00
Storefront certificateExpiring soon
11d left
MailHealthy
22/ 24 h healthy
00:0006:0012:0018:00

Seen on the map

Zones where they are, a beacon group inside one, the five places we check from. Hover a lamp.

A round lamp is a group of monitors at the place you give it, wearing the worst of them. A diamond is a beacon group: boxes in that network running checks from inside. A square is one of our own five places, coloured by what it last saw from there.

Confirmed first

One failed run proves little on its own. hostnag waits for 2 confirmations, a second location or a second consecutive run, before it opens an episode and nags your channels.

Quiet when you say so

Maintenance windows, one-off or repeating, silence a group or a monitor while you work, and Maintenance now starts one on the spot. Quiet hours hold non-critical chat, mail and text alerts until morning. Escalation nags a second route after the minutes you set go by unacknowledged, and every alert carries a one-click acknowledge link.

Nothing to install

Five places of our own; one plain script for what they cannot reach.

US East

IAD

US West

SJC

Frankfurt

FRA

Tokyo

NRT

Sydney

SYD

The Beacon

One line installs a plain script on a box in your network, under your own cron, launchd or Task Scheduler. It runs the same HTTP, port, DNS, ping and certificate checks from inside, feeds a link's internal ping, a status word or a certificate, and hostnag judges what it saw. Read it in full; uninstall removes all of it. How it works

Route to the right people

Groups, roles, routes

One organization. A group per client, product or office, each with its own alert policy and channels. Owners, admins, members and viewers; on Pro and Business a viewer sees only the groups you name.

Client A

api.client-a.example

mail.client-a.example

#client-a-alerts

ops@client-a.example

Critical only after hours

Every channel

The lamp is the lowest plan that includes it.

EmailFree
SlackFree
DiscordFree
Microsoft TeamsFree
TelegramFree
WebhookFree
SMSBusiness
PagerDutyPro
OpsgeniePro

Bring your monitors

Import from UptimeRobot, Better Stack, Pingdom, Uptime Kuma, Checkly, Cronitor, Gatus, Healthchecks.io, HetrixTools, Hyperping, Oh Dear, openstatus, Site24x7, StatusCake, Updown.io, Uptime.com or a CSV. Preview every monitor, then create up to your plan limit. An API key is used once and never stored.

Plans

Monthly or yearly, cancel any time; every new organization starts with 14 days of Pro. Every plan includes every monitor type. Every limit on the pricing page

Free

$0/ mo

For your own handful of hosts.

Monitors: 20
Beacons: 2
Groups: 3
Status pages: 1
Seats: 3
Every: 5min
Locations: 1
History: 30days
Channels: Email, Slack, Discord, Microsoft Teams, Telegram, Webhook
More: No packs

Start free

Pro

$19/ mo

For a team's sites, APIs and gateways.

Monitors: 100
Beacons: 10
Groups: 25
Status pages: 10
Seats: 10
Every: 1min
Locations: 3
History: 90days
Channels: Email, Slack, Discord, Microsoft Teams, Telegram, Webhook, PagerDuty, Opsgenie
More: Packs of 100 monitors at $15 a month, up to 4; packs of 10 beacons at $10 a month, up to 9

Start with Pro

Business

$79/ mo

For many groups: clients, products or offices.

Monitors: 500
Beacons: 100
Groups: ∞
Status pages: ∞
Seats: ∞
Every: 1min
Locations: 5
History: 365days
Channels: Email, Slack, Discord, Microsoft Teams, Telegram, Webhook, PagerDuty, Opsgenie, SMS
More: Packs of 100 monitors at $15 a month, as many as you need; packs of 10 beacons at $10 a month, as many as you need

Start with Business

Questions

All questions

Will one bad minute page me?

No. A failure needs to be confirmed, either a second location seeing it or a second consecutive run, before hostnag opens an alert.

What can hostnag watch?

Websites and APIs over HTTP, TCP ports for VPNs and gateways, ICMP ping, DNS records, TLS certificates, domain registrations, heartbeats for scheduled jobs, anything in your network through a Beacon on a box there, mail health, the names under a domain looked at daily for takeover risk, an office or ISP link pinged externally and confirmed internally, a vendor's own status page, and certificates or statuses reported from places hostnag can't reach on its own. Fourteen monitor types in all.

What does the Free plan include?

20 monitors in three groups, three seats, checks every 5 minutes from one location, alerts by email, Slack, Discord, Teams, Telegram and webhook, one status page, and 30 days of history. It costs nothing and needs no card.

Add a host. Hear about it first.

Start free