Watching 4.2M endpoints right now

Is your line
fast?

Zappline pings your websites and APIs every few seconds from 23 cities and tells you the instant your response time slows or drops. Not just up or down. How fast.

No credit card · 2-minute setup · cancel in one click

api.acme.io
42ms
response · live
200ms100ms0
uptime 99.98% · 30dp50 41ms · p95 92ms · p99 168ms▲ alert fires at >120ms for 3 checks

Keeping the line fast for

acme.ionorthwindStratusHeliaBytewaveCobaltLumen LabsFoundryParallaxDriftwoodacme.ionorthwindStratusHeliaBytewaveCobaltLumen LabsFoundryParallaxDriftwood
23
probe cities, 6 continents
from SF to Sydney
5s
fastest check interval
catch a slowdown in seconds
11s
median time to alert
before your users notice
What Zappline watches

Up or down is the old question. Speed is the real one.

Response-time tracking

Every check records DNS, TLS, time-to-first-byte and full load. Watch p50, p95 and p99 trend, not a binary up/down light.

Latency alerting

Set a threshold in milliseconds. When the line slows past it for N consecutive checks, you get paged, before users feel it.

API & transaction checks

Monitor JSON endpoints, assert on status, headers and body, and chain multi-step flows like login → cart → checkout.

SSL & domain expiry

Certificates and domains expire at the worst moment. Zappline warns you weeks ahead so the line never goes dark.

Real-time dashboards

A live oscilloscope per monitor, region heatmaps and a 1-year history you can scrub through to find the exact regression.

Status pages & SLA reports

Publish a branded status page and export SLA-grade uptime and latency reports your customers and auditors will trust.

How it works

Paste a URL. We do the rest, forever.

01

Drop in a URL

Paste a website, an API endpoint or a full transaction. No agent, no SDK, nothing to install. The first check runs in seconds.

02

We watch from 23 cities

Probes around the world hit your line on your interval, as tight as every 5 seconds, recording full timing from each region.

03

You hear from us only when it matters

Slowdowns and outages are confirmed across cities, then routed to Slack, PagerDuty or SMS, with the region and the numbers attached.

The probe network

Your users are everywhere. So are we.

A site that feels instant in Frankfurt can crawl in São Paulo. Zappline checks from 23 cities on 6 continents, so you see the slow path before the customer on it does, and you know exactly which region to fix.

  • Per-region p50 / p95 / p99 breakdowns
  • DNS, TLS handshake, TTFB and full-load timing
  • Tag a monitor to the cities your customers live in
San Francisco 11ms
Toronto 19ms
New York 14ms
São Paulo 28ms
London 9ms
Paris 12ms
Frankfurt 8ms
Lagos 33ms
Cape Town 41ms
Dubai 22ms
Mumbai 24ms
Singapore 17ms
Tokyo 13ms
Sydney 26ms
23 probe cities · checking every 10s
ALL SYSTEMS NOMINAL
Alerting that respects your sleep

Paged for real problems. Quiet for blips.

Zappline confirms a slowdown from multiple cities before it wakes anyone, so a single flaky probe never becomes a 3am page. Set thresholds on latency, not just downtime.

SlackPagerDutyOpsgenieSMSEmailWebhooksDiscordMicrosoft Teams
api.acme.io · checkout
p95 168ms → 940ms · confirmed in 4 cities
now
cdn.acme.io · assets
TTFB drifting up in ap-southeast
2m
acme.io · marketing
recovered · 38ms · all green
14m
status.acme.io
99.99% uptime this week
1h
Listening on 12 monitors
Public status pages

Show customers the line is fast.

Spin up a branded status page on your own domain in a click. Live latency, 90-day history and incident notes, all published automatically from the same checks that page your team.

status.acme.io Operational
API38ms
Checkout52ms
Dashboard44ms
CDN21ms

“Pingdom told us we were up. Zappline told us checkout had gotten three times slowerin Asia. We fixed it before a single ticket came in.”

— Priya N., Head of Platform at Northwind
Pricing

Recurring peace of mind, priced per line.

Start free, forever. Upgrade when you have more lines to keep fast.

MonthlyAnnual −20%

Solo

For a side project or a single product.

$0/mo
Start free
  • 5 monitors
  • 60s check interval
  • 3 probe cities
  • Email alerts
  • 7-day history
Most popular

Team

For startups that page when the line slows.

$31/mo
Start 14-day trial
  • 50 monitors
  • 10s check interval
  • All 23 probe cities
  • Slack, PagerDuty, SMS & webhooks
  • Public status page
  • 90-day history

Scale

For platforms with an SLA to defend.

$119/mo
Talk to us
  • 500 monitors
  • 5s check interval
  • Private probe locations
  • SLA reports & audit log
  • SSO / SAML
  • 1-year history

Find out if your line
is actually fast.

Paste a URL and watch the first check land in seconds. No card, no call.