sindresorhus/is-online

Health v2 · maintenance only

Adoption not part of the score

1357 stars · 88 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded

A JavaScript library that checks whether the internet connection is actually up, unlike navigator.onLine which only reports local network status. It runs parallel connectivity checks (HTTPS endpoints, DNS queries, captive portal test) in Node.js and the browser and resolves to a boolean.

Use cases

• check if the internet connection is up
• detect real internet connectivity in nodejs
• verify online status before making api calls
• check ipv6 connectivity
• detect captive portal internet access
• show online/offline indicator in a web app
• wait for network reconnection after going offline

When to choose

• you need to know if the internet is truly reachable, not just the local network
• you want a maintained, promise-based connectivity check with timeout and abort support
• you need the same check to work in both Node.js and bundled browser code
• you need to assert IPv4 or IPv6 connectivity specifically

When to avoid

• you only need local network interface status (navigator.onLine suffices)
• you need continuous connection monitoring rather than on-demand checks
• you cannot tolerate outbound requests to third-party endpoints
• you need low-level socket or ping-based diagnostics

Facets

library · maturity active

http-client networking developer-tools networking web-development developer-tools browser cross-platform connectivity-check internet-detection online-status ping-alternative captive-portal nodejs

Member repositories

For agents

markdown · JSON · MCP: product_card(name="sindresorhus/is-online")