findomain
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Findomain is a subdomain enumeration tool that uses Certificate TransparencyCertificate TransparencyA public, append-only log system maintained by various operators (Google runs several) that records every TLS certificate issued, letting anyone audit CAs for misissued or rogue certificates. logs and 54 passive APIs to discover subdomains.
findomain -t example.com --max-http-redirects 5 findomain -t example.com --no-discover --tcp-connect-threads 50 findomain -t example.com --no-discover FINDOMAIN_CONFIG_FILE=/path/to/custom/findomain.conf findomain -t target.com # In your config file (default location or specified by FINDOMAIN_CONFIG_FILE): lightweight_threads = 10 screenshots_threads = 5 import_subdomains_from = ["/data/subdomains.txt"] findomain -t example.com -i --http-status --lightweight-threads 150 --screenshots-threads 20 findomain --validate -f subdomains_file.txt -u valid_subdomains.txt findomain -t google.com -r --external-subdomains cat targets.txt | findomain -q --stdin --rate-limit 5 findomain --screenshots example.com:8080 findomain --screenshots https://example.com:443 findomain --targets example.com test.org --randomize cat targets.txt | findomain --stdin -t / findomain --user-agents-file ./agents.txt -t example.com findomain --certspotter-key <API_KEY> -t example.com findomain -t example.com --filter 'internal' --exclude 'test' --webhook-url http://your-webhook.com/notify findomain -t example.com --dns-resolver 8.8.8.8 --user-agent 'MyCustomAgent/1.0' findomain -t example.com --light-monitoring --http-timeout 30 findomain -t example.com --exclude-sources archiveorg c99 crtsh # Add to .findomainrc.yaml: # exclude_sources = "archiveorg c99 crtsh" findomain -t example.com -w wordlist.txt -i findomain -f targets1.txt -f targets2.txt -w wordlist.txt -r findomain --check-updates findomain --quiet -t example.com findomain -m -t example.com --ip findomain -t example.com --telegram-webhook https://api.telegram.org/bot<token>/<chat_id> findomain -t example.com --resolved -o unique-file findomain -t target1.com,target2.com --resolved findomain --target example.com --facebook-token <YOUR_FACEBOOK_TOKEN> findomain -t target.com -a crt.sh,virustotal findomain -t target.com -a sublist3r findomain -t example.com
Summary
Findomain is an open-source subdomain enumeration tool that queries Certificate Transparency logs and third-party APIs to find subdomains belonging to a target domain, and it is free to use. It runs as a command-line tool, with monitoring output pushed to Discord, Slack, or Telegram webhooks so results can feed into an existing alerting setup. It fits reconnaissance and OSINTOSINTOpen-source intelligence, collecting and analyzing information from publicly available sources. Investigators use it to learn about people, infrastructure or threats. work, making it a fit for red teamers, bug bounty hunters, and asset-discovery teams tracking a domain's exposed surface over time. It sits in the subdomain enumeration and asset-discovery category alongside other recon tooling, resolving subdomains in parallel and supporting DNS over TLSDNS over TLSA protocol that wraps DNS queries inside a TLS connection on port 853, preventing eavesdroppers from reading or tampering with hostname lookups. Cyber tools use it to keep reconnaissance and C2 traffic from leaking in plaintext.. First committed in 2019, it has drawn 24 contributors and 49 commits in the past year across 14 releases, though the most recent release was 389 days ago.
Findomain is a subdomain enumeration tool that uses Certificate Transparency logs and 54 passive APIs to discover subdomains.
How findomain helps
Which subdomains exist for a domain that I don't already know about?
queries Certificate Transparency logs and dozens of passive APIs in parallel, returning every subdomain those sources have seen for the target
Has a target domain grown new subdomains since I last checked?
runs on a schedule and pushes new findings to a Discord, Slack, or Telegram webhook, so a growing attack surface shows up as an alert rather than requiring a re-scan
Which of these discovered subdomains are actually alive?
resolves the found subdomains in parallel, using DNS over TLS if configured, and reports which names resolve versus which are dead
Can I fold subdomains I already gathered from another tool into this scan?
accepts imported subdomain lists from other tools and resolves them alongside what it discovers itself
Do I need to query over IPv4 or IPv6 specifically to match my network setup?
supports restricting queries to a specific IP version, so results reflect the resolution path actually available on the box running it
Languages
Command line
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Values are placeholders taken from each option’s declared default. Nothing is executed here — the output shown is a recording of a run that already happened.
Score card
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Shipping velocity releases a month, last 12 months
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Documentation quality release-notes rubric, 0–100
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Breaking-change discipline how rarely a release breaks users, and notice given
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Maintenance risk quiet time against its own cadence, maintainers
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Innovation & surface new capabilities, API and MCP surface
- Community health
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Contributor trend distinct committers, this year against last
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Maintainer concentration bus factor now against a year ago
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Issue backlog trend issues closed per issue opened, 12 months
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Responsiveness median time to a maintainer’s first reply
Nine scores for findomain, each built from the releases, notes and API history this site tracks — and, on Researcher and Business, where it stands among every measured tool in its category and how that has moved.
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Blank means never measured; nothing here is a filled-in zero.
Peer standings are included with Researcher and Business. See how this tool ranks against its competitors, using data we don't publish anywhere else.
See plans →Each score is 0–100 on a published rubric, derived from data this site already shows. A dimension we cannot measure says so — it is never scored 0 and never enters a rank.
How this is scored
- Shipping velocity — releases a month over the last 12 months, on a log scale where 16 a month scores 100. Needs 3 releases in the window.
- Documentation quality — the release-notes rubric published on the analytics page, unchanged.
- Breaking-change discipline — the share of releases carrying a breaking change (none scores 100, half or more scores 0). Only projects that label breaking changes are measured: a clean record cannot be told from an unlabelled one.
- Maintenance risk — quiet time measured against the tool's own release cadence (quiet longer than 90 days and three typical gaps scores 0), plus the number of active maintainers and whether contributors are growing, where known. Higher is lower risk.
- Innovation & surface — new capabilities in the feature ledger this year, API and MCP operations added, and the share of commits that are features: the mean of whichever we hold.
- Community health (open-source tools only) — each is a direction, not a size: contributors this year against last, the bus factor now against a year ago, and issues closed per issue opened, where steady scores 50, doubled 100 and halved 0; plus the median time to a maintainer's first reply (an hour scores about 100, a month or more 0). A commercial card has no repository and carries none of the four.
- Documented delivery (commercial tools) — when a vendor's documented new capabilities have slowed against its own baseline, that counts against the overall standing as heavily as two low dimensions. Steady delivery, or too little history to judge, leaves the standing alone; it is never a sixth score.
- Open-source tools are scored on repository signals; commercial tools on their published changelog. Ranks compare tools within one category and one profile and need at least five measured peers; the overall standing needs three ranked dimensions. Best-in-breed or consolidator is a shape, not a quality, and is never scored.
Release-note detail over time
See how much detail findomain puts in its release notes, quarter by quarter, and compare it with tracked tools in the same category. This history uses up to ten retained, reviewed notes per tool; sparse or blank older quarters may reflect that limit.
Checking release-note history…
Releases
41 entries
No entries match these filters.
- April 20231
- April 20223
- February 20222
- December 20211
- August 20211
- May 20212
- April 20211
- March 20211
- January 20211
- July 20201
- June 20202
- March 20201
- February 20202
- January 20204
- November 20192
- October 20194
- September 20195
- August 20193
- July 20192
- May 20191
- April 20191
Project health
Issue, contributor and maintainer activity in Findomain/Findomain, 2023-10 – 2026-09, as of 2026-09-25. Twelve-month figures first; the trend lines run the whole window.
- Contributors 2 ±0 vs prior 12 months
- Maintainers 1 +0 joined · −0 left, last 12 months
- Bus factor 1 committers behind half the commits
- Community-filed 100% of issues opened, last 12 months
- Median time to close 2.7 years first maintainer reply 21 hours
- Open backlog 2 of 164 issues ever filed
- Issues opened / month 0 · 0 communitymaintainers
- Open backlog 2
- Contributors / month 1
- Commits / month 6
- Stars 3,795
- bugs 20%
- other 80%
Counts from the project's public repository and git history; no individuals are identified. Maintainers are the committers covering 80% of the last year's commits. how we measure this
Libraries its release ships
What its latest release locks, checked against known advisories.None of its release's images build from a lockfile we can read.
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