Web · AI · Content Curation
JustSignal
Only the Substack articles that actually matter to you.
JustSignal reads every article from every Substack you follow, scores each one against your unique interest profile using Gemini AI, and surfaces only the content worth your attention — suppressing the noise before it reaches you.
Capabilities
How JustSignal works
AI Interest Interview
A Gemini-powered onboarding conversation that learns what you genuinely care about — the decisions you are navigating, where missing a development would cost you, and which topics are actually noise. The result is a tiered interest profile that drives all future scoring.
Relevance & Novelty Scoring
Every article in every feed you follow is scored 0–10 against your interest profile. Scoring factors both relevance and novelty — so you never see the fifth article on the same angle of a topic you have already absorbed, even when it scores well on relevance alone.
Concept Saturation Tracking
JustSignal tracks your exposure to each concept using 768-dimensional vector embeddings. As you read, saturation rises; resolved interests decay it. The effect is a feed that naturally shifts toward emerging ideas and away from concepts you have already covered thoroughly.
Signal Feedback Loop
Mark any article as +Signal (valuable) or -Signal (noise) with a single tap. These examples feed directly into future scoring calls, continuously calibrating the model to your actual judgement rather than relying solely on the initial interview.
Serendipity Channel
Articles that score low for your profile but are covered independently by three or more sources are surfaced in a dedicated discovery channel. This catches consequential developments you might not have known to look for — organic profile growth without algorithmic recommendation rabbit holes.
Gap & Blindspot Detection
JustSignal's Discover tab identifies topics you care about but are underserved on, and trending topics that none of your sources cover at all. It then recommends specific Substack publications to fill those gaps — keeping your information diet comprehensive, not just curated.
Access
Free during Alpha
JustSignal is free during the Alpha Testing Period. All you need is an email address and a password — no Substack account linking, no OAuth, no subscription access required. JustSignal uses Substack's public RSS and JSON API feeds.
Early users help shape the product. Feedback from the alpha period directly influences what gets built next, including any future commercialisation model.
Market
Market Analysis
Substack has grown to tens of millions of active readers, with a disproportionate concentration of high-value knowledge workers — investors, founders, researchers, and technologists — who subscribe to a significant number of publications. The platform's subscription model creates a unique problem: users pay for content but are overwhelmed by volume, and have limited tools to manage it.
Existing solutions (RSS readers, read-later apps, email filters) are generic: they organise content but do not filter it. They treat all articles from a subscribed publication equally. JustSignal addresses a fundamentally different problem — not aggregation, but intelligent prioritisation based on individual interest profiles.
The AI-powered content curation category is growing rapidly, but most products target broad social feeds or general web content. JustSignal's Substack-specific focus, combined with per-user interest modelling, concept saturation tracking, and adaptive feedback loops, represents a meaningfully differentiated position in this space.
Commercialisation pathways include a freemium subscription model (premium scoring depth, higher feed limits, advanced discovery features), white-label licensing to media companies, and integration partnerships with Substack or adjacent newsletter platforms as the ecosystem matures.
Use Cases
Who JustSignal serves
Investors & Founders
Stay current on AI developments, market shifts, and competitive intelligence across dozens of newsletters — without reading 200 items a week. JustSignal surfaces the signal your portfolio decisions actually depend on.
Researchers & Academics
Track emerging concepts in your field while the saturation system filters out repetitive coverage. Novel findings and outlier perspectives surface naturally; well-trodden ground recedes.
Technical Professionals
Monitor product launches, engineering advances, and industry shifts that affect your roadmap — without the noise of tangential coverage. Feed Intelligence shows you exactly how well each publication serves your interests.
Interested in JustSignal?
Try it at justsignal.app, or reach out to discuss commercialisation, licensing, or partnership opportunities.