JustSignalOnly the Substack articles that actually matter to you.
JustSignal reads every article from every Substack you follow, scores each one against your interests, and surfaces only the content worth your attention — suppressing the noise before it reaches you.
How It Works
Three things happen after you sign up:
1. You tell us what matters.
A short onboarding interview — powered by Gemini — identifies the decisions you are navigating, the topics where missing something would cost you, and the areas that feel relevant but are actually noise.
2. JustSignal ingests your feeds.
We read your Substack sources and score every article against your interest profile — factoring in relevance, novelty, and how saturated you already are on each concept.
3. Your feed shows only signal.
Articles are ranked and filtered. You see what matters. Everything else is suppressed. Your profile adapts as you read and give feedback.
All you need is an email address and a password.
JustSignal uses Substack's public RSS and JSON API feeds — the same ones any RSS reader uses. We do not connect to your Substack account, request access to your subscriptions, link to your reader, or interact with your Substack login in any way. There is nothing to authorise and nothing that can interfere with your existing Substack experience.
JustSignal is free during the Alpha Testing Period.
Early users help shape the product. Your feedback directly influences what gets built next.
How onboarding and the feed work
Onboarding
When you create your account, JustSignal runs a two-stage onboarding to build your interest profile.
Short Interview (Step 1)
Four quick questions establish your starting profile:
- Your depth level — Beginner, Practitioner, or Expert
- Your intent — Learn, Stay current, Invest, or Build
- Your core topics — the areas where missing something would actually cost you (up to 5 tags)
- Topics to avoid — what feels relevant but is actually noise for you (optional)
Deep Interview (Step 2 — Feed Suggestions)
Based on your answers, Gemini suggests 8-10 real, active Substack publications matched to your topics. Each suggestion is verified before it is shown to you. You select the ones you want to follow, or skip and add your own sources manually.
Once you confirm, JustSignal scores your first batch of articles and your feed is ready.
Signal Vocabulary
The feed uses a simple signal language you train over time:
+ Signal
This article was high value for you. Marking an article + Signal tells JustSignal to boost similar content in future scoring. A green border ring indicates it has been marked — the article stays visible in your feed.
- Signal
This article was noise. Marking - Signal removes it from your feed immediately and feeds it back into the scoring pipeline as a negative example — reducing the chance of similar articles appearing again.
Read
Marks an article as read. Combined with opening it, this builds your read confidence score, which JustSignal uses to track concept saturation — how much you have already absorbed on each topic — so genuinely novel content is always weighted higher.
Save
Saves an article for later without marking it read. Saved articles remain full-opacity in your feed until you mark them read or dismiss them.
Feed Intelligence Panel
Above your article feed, the Feed Intelligence Panel gives you a live view of how your filter is performing:
- Scored / Suppressed / Skipped — counts from the last ingest run
- Score distribution — a breakdown of how articles landed across the scoring range
- Concept saturation map — the 20 concepts you are most exposed to, each with a saturation bar showing how close you are to fully covering that topic
- Low-confidence notices — articles scored on excerpt only (RSS fallback) are flagged inline on the card so you know the score is provisional
You can trigger a manual Refresh Feed at any time, which re-runs the ingest pipeline and re-scores your sources.
Discovery Tab
The Discovery tab surfaces articles that JustSignal would normally suppress — but that multiple sources are independently covering. If three or more sources have published something similar, that breadth of coverage is a signal in itself, even if the topic does not yet match your profile.
Each Discovery card shows:
- Title and source
- One-sentence summary
- Covered by n sources — how many sources converged on this topic
You respond with:
- Interested — adds the article to your radar; if three or more of your Interested responses share a concept tag, JustSignal automatically suggests that topic for your profile
- Not for me — removes the card
Discovery is how your profile grows organically. When you keep finding the same emerging topic interesting, JustSignal notices and asks whether to add it.