How Restacks Actually Work on Substack

Published: September 2026

Most people treat a restack like a bigger, fancier like - a compliment with extra visibility attached. That undersells what's actually happening. A restack is the only mechanic on Substack that takes someone else's built-up audience and hands a slice of it to you for free, and understanding exactly how that works changes what you should be doing with the restack button, both on your own Notes and other people's.

What a restack actually is

A restack is Substack's version of a retweet or reshare: taking someone else's Note (or occasionally a post) and rebroadcasting it to your own subscribers and followers, optionally with your own comment attached above it. It shows up two places at once - in the original author's Notes feed with restack credit attributed to you, and in the home feed of everyone who follows you, many of whom have never heard of the original writer.

That second part is the entire mechanism worth understanding. WriteStack's breakdown of restacks puts it plainly: a restack is "the only Substack mechanic that borrows someone else's audience and hands it to you for free," which is why the restack count - not the like count - is what actually decides how far a Note travels. If a writer with 10,000 followers restacks your Note, your words land in front of a meaningful slice of those 10,000 people, cold. No subscription required on their part, no click required on yours. They just see it appear in their own feed the same way they'd see a Note from someone they already follow.

Why this matters more than it sounds like

Every other engagement type on Substack - likes, comments, even follows - stays contained within the audience that already found the content. A restack is the one action that actively crosses audience boundaries. Restacks are described as "the closest thing Substack has to a share button that crosses audience boundaries", and they only fire on Notes, not on regular likes or comments. If your actual goal is reaching people who don't subscribe to you yet - which is the entire growth mechanism Notes exists for - restacks are the specific lever that does that job, not raw posting volume and not likes.

What a restack signals to the algorithm

Beyond the immediate distribution boost, restacking functions as a targeting signal that shapes what Substack's recommendation system learns about you going forward. According to one detailed breakdown of the mechanic, when you restack a writer in your niche, "you're sending the algorithm a very specific message: my audience and this writer's audience have something in common" - and the system responds to that signal by starting to show your content to people who engage with similar writers. The same source draws a distinction between random and strategic restacking: restacking anything you vaguely like is "better than nothing," but consciously restacking writers whose audience actually overlaps with your own trains the algorithm to find your ideal readers meaningfully faster than random activity does.

This lines up with what Substack's own Head of Machine Learning has said about what the Notes algorithm optimizes for - the system is trying to match content to the readers most likely to act on it, and restack patterns are one of the clearest available signals of which audiences cluster together.

Two different kinds of restacking, two different jobs

It's worth separating what a restack does depending on whose content you're restacking:

• Restacking someone else's content signals audience overlap to the algorithm and puts your name (via your comment on the restack) in front of their followers - a way of borrowing relevance from writers already established in your niche.
• Restacking your own content gives an existing Note a second life in the feed. Because Notes have a short effective shelf life and a large share of your own followers weren't online when you first posted, resurfacing your own Note the next morning reaches the portion of your audience that missed it the first time - one write-up reports 20-30%+ more views from this specific tactic, and a related account frames it similarly: restacking your own older Note gives it "a completely fresh life" since roughly half your current audience wasn't around for it the first time.

Both are legitimate uses of the same button, but they're solving different problems - one borrows someone else's reach, the other recovers reach you already earned but missed.

A specific, low-effort tactic worth adopting

One tactic surfaces repeatedly across creators who've studied this: restack a few relevant Notes from other writers in your niche before posting your own. The logic is that this "warms up your presence" in the feed and signals audience relevance right before you ask the algorithm to distribute something of your own - rather than showing up cold and immediately asking for distribution. It costs nothing beyond a few minutes of genuine engagement with other writers' work, which is itself a reasonable thing to be doing anyway.

Why restacking randomly underperforms restacking deliberately

The temptation is to restack anything that gets a reaction out of you, but the audience-overlap signal only works if the writers you restack are ones your actual audience would also want to follow. Restacking wildly unrelated content dilutes that signal rather than sharpening it - the algorithm can't learn "these audiences overlap" from a pattern that has no consistent theme. Being selective about who you restack, sticking to writers genuinely adjacent to your own niche, is what turns restacking from a vague good habit into an actual targeting tool.

How to actually get more restacks on your own Notes

Since restacks are the mechanic that matters most for reach, it's worth writing with that specifically in mind, not just optimizing for likes:

• Write Notes that give someone a reason to want their own followers to see it - a genuinely useful framework, a sharp reframe of a common problem, or something quotable enough that restacking it (with a comment) makes the restacker look good to their own audience
• Avoid the format failures covered in the broader Notes-mistakes research - a Note has to clear the bar of "worth resharing," which is a higher bar than "worth a quick like"
• Notes that invite a reply also tend to invite a restack, since both actions come from a reader who was engaged enough to want to do something more than scroll past

The bottom line

A restack isn't a bigger like - it's a distribution event that crosses audience boundaries in a way nothing else on the platform does, and it doubles as a targeting signal that shapes who the algorithm shows your future content to. Treating restacks as the metric to optimize for, rather than likes, and being deliberate about who you restack rather than restacking at random, is the difference between using the feature passively and using it as an actual growth lever.

NotesIQ tracks restacks alongside likes and replies, so you can see exactly which Notes are actually earning distribution - not just reactions.