PlotStack — Newsletter Analytics

Your newsletter metrics, organized in a single local dashboard.

PlotStack brings together in one dashboard the metrics Substack spreads across its stats page, its growth page, the posts dashboard and the Notes tab, and tells you in plain sentences what stands out. It works on the session you already have open in Chrome: no account to create, no API keys to paste, no server in between. The extension reads the stats of your own publication and keeps them on your computer. FINDINGS The Overview writes down what deserves your attention: a note or a post far above your usual, which trait of your notes performs best, how many signups a handful of notes bring in, which source is your main way in, your best week, or when you'll reach your next milestone. Every piece is compared with your previous 30, never with other newsletters, and every finding shows its evidence. Anything below its threshold stays out. SEVEN VIEWS • Overview — how your newsletter is growing, subscribers, open rate, clicks, the subscriber curve and every finding. • Audience — subscribers and followers on the same chart, countries, retention, your loyal core (your most active readers) and publications that share readers with you. • Growth — records, daily visits, the Substack network effect, acquisition sources with their conversion, and signups and unsubscribes. • Notes — where your notes are seen and by whom, a day-by-hour posting schedule, attributed signups and the full searchable list. • Posts — a sortable table with per-post metrics, open rate and CTR per post, reading beyond the inbox, a subject-vs-content diagnosis, and cuts by day, section and length. • Postcard — a card with your public numbers ready to share: your period, your latest milestone or your best week, in five layouts, portrait, square or landscape (Substack's post preview size), and in your logo's color. • Data status — which sources responded and when the last sync happened. IN ENGLISH OR SPANISH The interface follows your browser's language: Spanish if it prefers it, English otherwise. Dates and numbers use each language's format. NUMBERS YOU CAN TRUST • Aggregate rates are weighted by sends; rates are never averaged. • A cut with few sends is flagged as a small sample instead of being presented as a finding. • Missing data is shown as missing, not as zero. • Growth with no prior baseline never becomes "+100%". • If a Substack source fails, the previous value is kept and Data status says so; nothing is filled in with zeros. PRIVACY • There is no PlotStack server. No telemetry, no usage analytics. • Your cookie values are never read or stored: the extension only checks that a Substack session exists. • Subscriber emails and individual profiles are discarded before anything is saved. Only aggregate metrics are kept. • Paid subscriber and revenue figures are hidden by default, and every PNG capture hides them again, even if you show them on screen. • "Disconnect" deletes the saved metrics. It doesn't sign you out of Substack. EXPORT Capture any view or a single card as a PNG — to the clipboard or to a file — and download the posts and notes tables as CSV. Everything is generated in your browser. LIMITATIONS This version supports publications on *.substack.com; custom domains are not supported. PlotStack uses the read-only internal endpoints of Substack's own dashboard, which are not publicly documented and may change. PlotStack is open-source software and is not affiliated with Substack Inc.