How Blackout Map detects internet blackouts

Blackout Map watches whether each country's internet is still reachable from the outside world, and combines two independent signals so that one faulty measurement can't paint a country red.

1. Our own probes

Every 5 minutes we ping 5,798 hosts inside more than 200 countries: RIPE Atlas anchors and probes, public DNS resolvers listed by public-dns.info, and — where those are scarce — network gateways inside the country's own address space (found through RIPEstat). Hosts are spread over as many different networks per country as possible, so a single provider having a bad day doesn't look like a national outage.

The host list is rebuilt and re-verified every week: every candidate must answer before it is used, because a dead host looks exactly like a blackout. Hosts on global cloud providers are excluded — their location says little about the country they're listed in.

Before judging any country, each cycle checks six large global services (Cloudflare, Google and Quad9 DNS, OpenDNS and two root servers). If our own server can't reach them, the cycle is discarded.

Our probes run from one server in Germany, so we also guard against problems on our own route. If several countries in one region stop answering at the same moment while IODA sees nothing there, we treat it as our route, not theirs. And when our probes see a country drop, volunteer probes on three other continents (Globalping) re-test the hosts we could not reach: if they can reach them, our probes are ignored for that country; if they can't either, the outage is marked as confirmed from other locations.

2. IODA

The Internet Outage Detection and Analysis project at Georgia Tech tracks BGP routing (are a country's networks still announced on the internet?) and large-scale active probing for every country. We use its open alerts as a second opinion, and as the main source for places with few reachable hosts.

How a status is decided

• Operational — networks reachable as usual.
• Degraded — noticeably fewer networks reachable than normal, or only one source sees a problem.
• Partial outage — a large share of the country's networks is unreachable.
• Blackout — almost nothing reachable, confirmed by both sources, or BGP routes withdrawn.
• No data — no reliable measurements right now.

"Normal" is measured per country: we compare how many hosts answer now with what is typical for that country over the last day. During an incident that baseline is frozen, so a long outage never quietly becomes the new normal.

Each source gives a level from normal to blackout. If either source sees nothing wrong, the country is shown as degraded at most; otherwise the two are averaged. Alerts that IODA has had open for more than a week while our probes see nothing are treated as a changed network, not an outage.

Reported shutdowns and blocks

Some restrictions don't make a country unreachable: blocked social media, or a shutdown in one region while the rest of the country stays online. For these we show the Internet Society Pulse shutdowns tracker, which records government-ordered shutdowns and blocks worldwide. Countries with an ongoing reported restriction are hatched on the map. Shutdown data provided by Internet Society.

Submarine cables

Country pages show how a country is connected by sea — number of submarine cables, landing stations and a resilience score — with recent cable incidents, from GeoCables (CC BY 4.0). This explains why some places are fragile, but never changes a country's status.

The optional cable layer on the map (Settings → Map layers, beta) draws cable routes from OpenStreetMap (© OpenStreetMap contributors, ODbL). OpenStreetMap only maps part of the world's cables, so the layer is incomplete.

Earthquakes and other context

The map shows earthquakes of magnitude 5 and up from the last 7 days (USGS), each linked to the nearest country, so you can see whether its internet held. They can be hidden in Settings or in the legend. As an optional beta, Settings can also add outages and traffic anomalies reported by Cloudflare Radar (CC BY-NC 4.0). None of these change a country's status.

The Realistic and Simple map palettes and the Realistic ocean are drawn from NASA Blue Marble (public domain); the deserts of the Simple palette also follow the Köppen-Geiger climate map by Beck et al. (2018) (CC BY 4.0).

Alerts, feeds and embedding

Follow a country (Alerts in its panel) to get a browser notification when its internet goes down or recovers; on iPhone and iPad this works once Blackout Map is added to the Home Screen. Every country has an RSS feed, there is a worldwide feed at /feed.xml, and every country page has a live status card you can embed on your own website.

Our own status data (/data/status.json) may be reused under CC BY-NC 4.0: credit Blackout Map with a link, and don't use it commercially. For commercial use, ask us first via Contact.

Limits

We see reachability, not content. Censorship of specific apps or websites, throttling that keeps connections working, and outages inside networks that don't affect outside reachability are not visible here. Small countries with few public hosts rely on IODA alone.

How often is the map updated?

Every 5 minutes. A status only changes after it has held for 10 minutes (15 minutes to recover), so short blips do not flash the map.

Can Blackout Map see blocked websites or apps?

No. It measures whether networks inside a country are reachable from the outside. Blocks on specific apps or websites, and slow-but-working connections, do not show up.

Where does the data come from?

From our own probes (RIPE Atlas anchors and probes, public DNS resolvers and network gateways, re-verified weekly), from IODA at Georgia Tech, reported shutdowns provided by Internet Society (Pulse), and — as background only — submarine cable data from GeoCables and OpenStreetMap, earthquakes from USGS and, optionally, Cloudflare Radar.

Can I get an alert when a country goes offline?

Yes. Open a country on the live map and tap Alerts to get a browser notification when its internet goes down or recovers, or follow every blackout worldwide in Settings. Every country also has an RSS feed.