5 Shodan Alternatives (Freemium & Open-Source)

Shodan is a search engine for internet-connected devices — servers, IoT, cameras and other hardware exposed to the open internet. It's freemium, with a free tier for basic lookups and paid plans for deeper search. Because it indexes devices whether or not their owner realised they were reachable, it's dual-use: the same lookup that helps you check your own exposure can be used to find someone else's.

Other tools in this space split roughly two ways. Some are hosted search engines like Shodan itself, indexing the internet continuously so you can query it. Others are scanners you run yourself, sweeping ranges of addresses on demand rather than searching a pre-built index.

What matters when choosing between them is similar either way: is it free or does useful search depth sit behind a paid tier, is it a hosted product or something you self-host, and does it require an account to query. The five below span both approaches.

Looking at the original? See Shodan in the directory.

Alternatives

CensysFreemium · dual-useSearch engine for internet-facing hosts, certs, and services.Also a freemium search engine for internet-facing hosts, certificates and services, making it the closest like-for-like to Shodan's hosted-index approach.

ZoomEyeFreemiumCyberspace search engine mapping internet-exposed devices, services and components.A freemium cyberspace search engine mapping internet-exposed devices, services and components — another hosted index to query instead of Shodan's.

NetlasFreemiumInternet-wide scanning and attack-surface search platform.A freemium internet-wide scanning and attack-surface search platform, offering a similar hosted-search route.

GreyNoiseFreemiumLabels internet background scan and attack traffic to separate noise from real threats.Freemium and focused specifically on labelling internet background scan and attack traffic, useful if what you need is to separate noise from real threats rather than a general device index.

MasscanOpen sourceInternet-scale TCP port scanner able to sweep huge address ranges very fast.Open-source and free, if you would rather run your own internet-scale TCP port scanner over a chosen address range instead of querying someone else's index.

Browse the full tools directory →

Common questions

Is there a free alternative to Shodan?

Masscan is open-source and free to run yourself. Censys, ZoomEye, Netlas and GreyNoise are all freemium, like Shodan — usable at a smaller scale for free, with paid tiers for deeper search.

Do these tools need an account?

Hosted search engines like Censys, ZoomEye and Netlas typically require sign-up, similar to Shodan. Masscan is a self-run scanner and does not require an account.

What's the difference between a search engine and a scanner?

Shodan, Censys, ZoomEye and Netlas continuously index the internet so you can query a pre-built database. Masscan instead sweeps address ranges you point it at on demand, and GreyNoise focuses on classifying scan traffic rather than indexing devices.

Can these tools expose my own devices?

Yes — indexes like Shodan, ZoomEye and Netlas can surface internet-facing devices you run (routers, cameras, NAS) even if you did not realise they were reachable. Checking your own exposure is a reasonable use; scanning or querying devices belonging to someone else raises legal and ethical questions covered at /learn/ethics-and-law.