# ChangeSignal > ChangeSignal detects company changes that reveal buying intent — hiring, funding, tech-stack switches, leadership changes, layoffs, new business registrations, permits, and more — from public data sources. Every signal is event-sourced and traceable to the raw document and snapshot diff it came from, so the evidence is auditable rather than a black box. ## What makes the data distinctive - Time-series deltas, not static snapshots: we record *changes over time* (a first-ever role, a provider switch, an exec disappearing from a /team page). These cannot be backfilled after the fact. - Verifiable provenance: each signal links to the underlying public document and the diff that triggered it. - Coverage of sources most vendors skip: state WARN layoff notices, local business registrations and permits, DNS/MX provider switches, and public GitHub org membership changes. ## Signal feeds - [Composite buying signals](https://getchangesignal.com/signals/composite): The strongest signals of all: multiple independent sources lining up on the same company within a short window — fresh funding plus a sales-hiring burst, a new-market subdomain plus regional hiring, an infra change plus IT hiring. Feed: https://getchangesignal.com/signals/composite/feed.xml - [Companies that just raised funding](https://getchangesignal.com/signals/funding): Fresh financing (detected from SEC Form D filings and press wires) is the single strongest B2B buying trigger — budgets unlock and priorities reset. Feed: https://getchangesignal.com/signals/funding/feed.xml - [Companies expanding into new markets & products](https://getchangesignal.com/signals/expansion): New region subdomains, product launches, pricing changes, new customer logos, and partner additions — detected from certificate logs and web-page diffs. Feed: https://getchangesignal.com/signals/expansion/feed.xml - [Companies changing their tech stack](https://getchangesignal.com/signals/tech-adoption): Email/DNS provider switches and new tools appearing across job descriptions — detected from DNS record diffs and JD tech mining. Feed: https://getchangesignal.com/signals/tech-adoption/feed.xml - [Companies that just started advertising](https://getchangesignal.com/signals/advertising): Companies turning on paid ads or jumping ad volume, detected from the Meta Ad Library — a clear growth-investment signal. Feed: https://getchangesignal.com/signals/advertising/feed.xml - [Companies with new executives](https://getchangesignal.com/signals/leadership-change): New executives detected from /team page diffs, SEC 8-K Item 5.02 filings, and press releases — a classic first-90-days buying trigger. Feed: https://getchangesignal.com/signals/leadership-change/feed.xml - [Companies that just won government contracts](https://getchangesignal.com/signals/government-contract): Federal award activity detected from USAspending.gov — budget plus new compliance, staffing, and delivery obligations. Feed: https://getchangesignal.com/signals/government-contract/feed.xml - [Companies actively shipping mobile apps](https://getchangesignal.com/signals/app-activity): Bursts of app version releases, detected from the iTunes lookup API — active investment in the mobile product surface. Feed: https://getchangesignal.com/signals/app-activity/feed.xml - [Companies experiencing reliability incidents](https://getchangesignal.com/signals/incident): Repeated public status-page incidents, detected from Statuspage/Instatus feeds — a candid signal of reliability pain. Feed: https://getchangesignal.com/signals/incident/feed.xml - [Newly registered businesses](https://getchangesignal.com/signals/new-business): Freshly registered businesses, detected from state business-registry open data — buying their first of essentially everything. Feed: https://getchangesignal.com/signals/new-business/feed.xml - [Businesses pulling permits & liquor licenses](https://getchangesignal.com/signals/permit): Build-out permits and liquor-license applications, detected from Socrata open-data APIs — fire months before a business opens or appears in any static directory. Feed: https://getchangesignal.com/signals/permit/feed.xml - [Local businesses with listing changes](https://getchangesignal.com/signals/local-change): Rating drops, reopenings, and hours changes on local listings, detected from the Yelp Fusion API — operational shifts at local businesses. Feed: https://getchangesignal.com/signals/local-change/feed.xml - [Companies announcing layoffs](https://getchangesignal.com/signals/layoffs): WARN layoff and closure notices from state labor departments. A counter-signal for prospecting — but a buying trigger for consolidation and automation tooling. Feed: https://getchangesignal.com/signals/layoffs/feed.xml ## Cross-cutting surfaces - [Latest signals (global RSS)](https://getchangesignal.com/feed.xml): every newly detected signal across all types. - [Trend indexes](https://getchangesignal.com/trends): weekly aggregates (e.g. hiring index, funding velocity) computed from the signal history. - [Tech stacks & switching](https://getchangesignal.com/tech): which companies adopted or dropped a given provider, by provider. - [Local signals by metro](https://getchangesignal.com/local): new registrations, permits, and layoff notices by city/jurisdiction. - [Company directory](https://getchangesignal.com/companies): per-company signal history. ## API (for agents) Public, read-only JSON. No auth required. CORS-open. The moat — verifiable evidence URLs + the dated, immutable change history — is fully exposed; only the AI buying-intent interpretation and suggested outreach angles are reserved for Pro. - Catalog: https://getchangesignal.com/api — self-describing index of endpoints and valid change-domain slugs. - Company dossier: https://getchangesignal.com/api/company/{slug} — company metadata, active buying-intent signals, and the full dated change history (each event with its public evidence link). Returns 404 if the company has no active signals. - Recent changes firehose: https://getchangesignal.com/api/changes — cross-company stream of dated changes. Optional query params: `domain` (one change-domain slug, e.g. hiring, fundraising, tooling) and `limit` (1–200, default 60). Example: https://getchangesignal.com/api/changes?domain=hiring&limit=50. Every dated change is also distributed as RSS at https://getchangesignal.com/changes/feed.xml (and per-domain at https://getchangesignal.com/changes/{domain}/feed.xml) for subscription-based ingestion. ## Index - [Sitemap](https://getchangesignal.com/sitemap.xml) - [All signal feeds](https://getchangesignal.com/signals) - [API catalog](https://getchangesignal.com/api) - [Learn (methodology & guides)](https://getchangesignal.com/learn)