colly
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Colly is a Go framework that lets you build web scrapers and crawlers to extract structured data from websites.
ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
defer cancel()
c := colly.NewCollector()
c.Request("GET", "https://example.com", nil, ctx, nil)
q, _ := queue.New(4, &queue.InMemoryQueueStorage{MaxSize: 10000})
// ... add URLs ...
go func() {
time.Sleep(5 * time.Second)
q.Stop()
}()
q.Run(c)
html.ForEachWithBreak(".item", func(e *colly.HTMLNode) bool {
if e.Attr("data-skip") == "true" {
return false // Stop iteration
}
fmt.Println(e.Text)
return true
})
var items []MyStruct
err := collector.UnmarshalJSON(resp.Body, &items)
if err != nil {
log.Fatal(err)
}
func Handle(w http.ResponseWriter, r *http.Request) {
c := colly.NewAppengine(colly.AppengineCtx(r.Context()))
// ...
}
Summary
colly is an open-source Go library for building web crawlers, scrapers, and spiders, free to use in any project that imports it. It handles the mechanics of crawling directly in code rather than as a standalone service: cookie and session handling, request delays and per-domain concurrency limits, caching, robots.txt compliance, and context-based cancellation so requests can be stopped mid-crawl. This suits developers building data collection pipelines, OSINTOSINTOpen-source intelligence, collecting and analyzing information from publicly available sources. Investigators use it to learn about people, infrastructure or threats. tooling, or archiving jobs who want that logic in Go rather than assembled from separate scraping utilities. First committed in 2017 and now at 140 contributors, it sees modest ongoing activity with 25 commits in the past year, though its last release was over 500 days ago.
Colly is a Go framework that lets you build web scrapers and crawlers to extract structured data from websites.
How colly helps
How do I pull structured data off a site without hand-rolling HTTP, retries, and HTML parsing?
a collector walks the pages you point it at and hands parsed HTML elements to callbacks you register, so extraction logic sits in Go code instead of glue scripts
How do I keep a crawl from hammering a target site or getting blocked?
per-domain concurrency limits and request delays are set on the collector, and robots.txt rules are honored automatically before a request goes out
How do I stop a long-running crawl cleanly when I've got what I need?
requests carry a context, so cancelling it or hitting a deadline halts in-flight requests, and a running queue can be stopped mid-crawl once a match condition is met
How do I avoid re-fetching pages I've already scraped in an earlier run?
responses are written to a cache, so a repeated visit to the same URL is served from disk instead of hitting the network again
How do I keep a crawl within a fixed budget of requests?
a cap on the total number of requests a collector will make stops the crawl once it's reached, regardless of how many links remain queued
Will a redirect chain let a scraper wander outside the domains I meant to target?
URL filters are checked on every redirect hop, not just the initial request, so a redirected page landing outside the allowed pattern is dropped
Languages
Command line
| option | found in | since | description |
|---|
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 colly, 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.
Score cards are part of every paid plan.
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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 colly 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
5 entries
No entries match these filters.
- March 20251
- November 20191
- February 20191
- August 20181
- May 20181
Project health
Issue, contributor and maintainer activity in gocolly/colly, 2023-10 – 2026-09, as of 2026-09-25. Twelve-month figures first; the trend lines run the whole window.
- Contributors 13 −1 vs prior 12 months
- Maintainers 1 +1 joined · −2 left, last 12 months
- Bus factor 1 committers behind half the commits
- Community-filed 95% of issues opened, last 12 months
- Median time to close 38 days first maintainer reply 38 days
- Open backlog 146 of 580 issues ever filed
- Issues opened / month 0 · 0 communitymaintainers
- Open backlog 146
- Contributors / month 1
- Commits / month 3
- Stars 25,518
- questions 5%
- other 95%
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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