The state file

indexnow keeps what makes scheduled runs idempotent in one sqlite file: .indexnow/state.sqlite in the working directory, --state <path> or INDEXNOW_STATE elsewhere, memory for a run that keeps nothing (a read-only container, a one-off --dry-run). Nothing opens it before a store is asked for: list, --version, help and a configuration that does not build never touch it. It is created on first use, its directory with mode 0700, in WAL mode (a cron run and a manual one do not lock each other out), the tables created if missing.

Table	What	Who reads it
indexnow_cache	a PSR-16 cache: the debounce window (debounce.store = state, keys indexnowkit_<sha1 of the URL>, TTL debounce.per_url), the consecutive-403 counters per host, the robots.txt cache of the pre-flight	submit, sitemap, check (the probe), status
indexnow_submissions	the history: one row per URL of a result, the rows of one result share a batch (the schema of the history package; history.pdo.table renames it)	history, status, check
indexnow_sitemap_seen	the fingerprint of every sitemap URL announced so far (URL plus <lastmod>, or none) and when	sitemap --new-only

What it means: a URL announced within the last debounce.per_url seconds (600) is not sent again by the next run — --force overrides; a sitemap URL announced once is not sent again by --new-only until its lastmod changes; history --purge removes records older than history.retention_days. No keys are stored. No backup needed: losing the file costs one full re-announcement (the engines de-duplicate). Do not put it under the document root.

check prints state: <path> (writable | read-only | not created yet) (cli.state, a warning when it cannot be written) and probes the debounce store through it (debounce.store). In CI, cache the directory between runs (actions/cache with path: .indexnow); in Docker, mount the working directory on /work.

The classes behind it (IndexNowKit\Cli\State\*) are internal until 1.0: the shape of the file may change in a minor, and a run then starts as if the file were new.