Assetfinder Alternative — Free Online Subdomain Finder
Assetfinder is tomnomnom's minimalist Go binary for finding subdomains and related assets from a handful of trusted passive sources. It is small, fast, and built to be piped into the next tool in your recon chain. It is also a Go install, terminal-only, and outputs names with nothing else — no IPs, no ports, no ASN. SubDomainsFinder.com covers the same passive enumeration ground from any browser and returns IP, port, ASN, and CDN data alongside each subdomain with no setup.
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TL;DR — when to use which
- Use SubDomainsFinder when you want a quick browser-based view of a domain's subdomain surface with IP, port, and ASN attached — no Go install, no pipeline assembly.
- Use Assetfinder when you are working inside a tomnomnom-style recon pipeline (assetfinder → httpx → nuclei) and need clean one-name-per-line output the next tool can consume directly.
- Use both for fast browser triage on new targets alongside an automated Assetfinder pipeline for large-scope enumeration.
What is Assetfinder?
Assetfinder is a small Go tool by Tom Hudson (tomnomnom), hosted at github.com/tomnomnom/assetfinder. The design philosophy is Unix applied to recon: one tool, one job, clean output, easy to compose. It queries crt.sh, certspotter, hackertarget, threatcrowd, Wayback Machine, VirusTotal, and findsubdomains — printing discovered assets and subdomains to stdout, one per line, deduplicated.
Without flags, Assetfinder returns both related assets (domains sharing apparent ownership) and subdomains. With --subs-only it restricts output to subdomains of the supplied domain — the form most bug bounty hunters use because it composes cleanly into subdomain-probing pipelines. The classic pattern isassetfinder --subs-only example.com | httpx -silent — live HTTPS subdomains in one shell command.
# Install (requires Go)
go install github.com/tomnomnom/assetfinder@latest
# Subdomains and related assets
assetfinder example.com
# Subdomains only
assetfinder --subs-only example.com
# Classic pipeline
assetfinder --subs-only example.com | httpx -silent | tee live.txtFeature comparison
| Feature | SubDomainsFinder | Assetfinder |
|---|---|---|
| No installation required | ||
| Browser-based UI | ||
| Passive subdomain discovery | ||
| Pipeline / CI integration | ||
| IP addresses per subdomainAssetfinder returns names only; pair with httpx | ||
| Open ports detection | ||
| ASN & hosting provider | ||
| Related-asset discovery (sibling domains) | ||
| Single-flag simplicity | ||
| Multiple data sourcesAssetfinder queries fewer sources than Subfinder | ||
| Free to use | ||
| Open source |
Yes No Partial / limited
Where Assetfinder excels
- Minimalism and pipeline compatibility. One of the cleanest Unix-philosophy recon tools. Plain deduplicated stdout that every downstream tool — httpx, nuclei, gf, anew, dnsx — accepts without translation.
- Single-flag simplicity. No provider config, no API key vault, no daemon to start. You type the command, the names appear. A gentle entry point for new users learning a recon stack.
- Related-asset discovery. Without
--subs-only, Assetfinder surfaces sibling domains and related assets — useful for broad organization footprinting that most subdomain-only tools miss. - tomnomnom ecosystem trust. Part of a small family of interoperating tools (gau, waybackurls, gf, meg, anew) broadly trusted by the bug bounty community. Tool choices that compose with established conventions have real value.
Where SubDomainsFinder has the edge
- No Go install, no terminal needed. Assetfinder requires a working Go environment or a pre-built binary. SubDomainsFinder needs a browser — including on borrowed laptops, client workstations, tablets, and Chromebooks.
- IP, port, ASN, and CDN data in one view. Assetfinder returns names. Everything else — does it resolve, what is the IP, what ports are open, which ASN — requires another tool. SubDomainsFinder attaches all that context by default.
- Broader source coverage. Assetfinder queries a relatively small source set. SubDomainsFinder aggregates from CT logs and public scan data without API key configuration, typically returning equal or better coverage for a single ad hoc lookup.
- Active maintenance. Assetfinder still works but isn't under active development. Sources change, endpoints break, and an unmaintained tool slowly loses coverage as the OSINT landscape evolves.
- Usable by people who don't live in a terminal. Security managers, analysts, and non-technical stakeholders can use SubDomainsFinder. Assetfinder is for CLI-comfortable engineers only.
Which tool is right for you?
Pentesters & bug bounty
Keep Assetfinder in your pipeline if you use the tomnomnom toolchain — it composes well with httpx, gf, and nuclei. Reach for SubDomainsFinder for quick browser triage on new targets or a sanity check with IP and port context attached.
Blue teams & defenders
SubDomainsFinder is the lower-friction tool for spot audits and inventory checks. Assetfinder works well in scheduled recon scripts paired with anew for diffing, but lacks built-in alerting — for serious monitoring use Findomain or a Subfinder-based pipeline.
Sysadmins & IT teams
For ad hoc questions about subdomain exposure, SubDomainsFinder gives you an answer in seconds without installing anything. Assetfinder is worth the Go install only if you are building a recurring recon workflow and want CLI output you can store, diff, and pipe into other tools.
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