How the Instagram Algorithm Works: Feed, Reels, Explore

There is no single Instagram algorithm. Instagram says so itself: it uses a set of algorithms, classifiers and processes, and each part of the app, such as feed, stories, explore and reels, has its own ranking system built for how people use that surface. Feed and stories lean on who you already follow and interact with. Explore and reels lean on what is performing well and what you have liked before.

This guide goes through each surface and the signals Instagram has described, then turns the split into design choices for anyone building a visual app. If that is you, a white-label Instagram-style social app starts you with posts, reels, stories and a follow graph in one codebase. Everything said about Instagram comes from its own pages, and the main explainer is dated May 31, 2023, so treat details as of October 2026 as possibly changed.

Many rankers, not one algorithm

The word algorithm suggests one formula that decides who sees what. Instagram's explainer describes something more modest. Each surface has a different job, so each has its own model.

• Feed is where you see posts from accounts you follow, plus some suggested posts.
• Stories is the row of circles at the top, mainly your closest accounts.
• Explore is for discovering accounts and posts you do not yet follow.
• Reels is a full-screen stream of short videos, mixing accounts you follow with others.

Behind each surface, the process is the same in outline. The system gathers posts that could be shown, looks at what it knows about the viewer, the post and the person who posted it, and predicts how likely the viewer is to take certain actions. It then orders the candidates by those predictions. What changes from surface to surface is which actions it predicts and which signals count most.

This matters for a creator because a post is judged more than once. A photo may rank well in feed because followers like it, and never appear in explore because it did not gather much attention beyond them. For a builder, it matters because it shows that you can launch with one simple ranker and add the others as the app grows. We covered the short-video version of this idea in how the TikTok algorithm works; Instagram differs in that its main surface is a follow graph, not a single recommended stream.

Feed and stories: relationships first

Feed

Instagram lists the most important feed signals in order. First is your activity: what you like, share, save and comment on. Second is information about the post, such as how popular it is and when it was posted. Third is information about the person who posted, including how often people interact with them. Fourth is your history with that person, such as how often you comment on their posts.

From these, the system predicts how likely you are to spend time on a post, comment, like, share it, or tap through to the poster's profile. A post with a high predicted chance of those actions moves up. Notice what is not on the list: a fixed rule that says photos beat videos or the reverse. The ranker is built around you, so two members who follow the same account can see different posts from it in different order.

Stories

Stories ranking is described as relationship-first. The main signals are your viewing history, meaning how often you watch an account's stories; your engagement history, such as likes and direct messages you have sent to the account; and closeness, which Instagram describes as how likely you are to be friends or family. The system predicts whether you will tap into a story, reply to it or skip it.

This explains why the same few accounts appear first every day. It is also a reason to give members a way to say who matters. A close friends list, which Instagram offers for stories, turns a guessed relationship into a stated one, and it is cheap to build.

Reels and explore: interests first

Instagram says people use explore to find new content and creators and use reels to be entertained. The signals reflect that difference.

Explore

For explore, the lead signal is information about the post, meaning how popular it is across other people, including how quickly it collects likes, comments, shares and saves. Next comes your activity in explore, which shows what kinds of content you open. Then your history with the person who posted, and finally information about the poster, such as follower count and engagement. The predictions are about whether you will like, save or share.

Reels

For reels, the first signal is your activity: what you like, save, reshare and comment on. Then your history with the poster, then information about the reel itself, including its audio, its visuals and its popularity, and finally information about the poster. The predicted actions are resharing, watching to the end, liking, and visiting the audio page.

The audio page prediction is a clue to the product. A reel is connected to a sound, and tapping the sound leads to other reels using it. That makes audio a graph of its own. If you want remix and audio features in your app, plan the sound library as part of the feed model, not an extra. Our Instagram clone features page shows the audio library and the remix link back to the original clip.

Signals by surface

This table collects what Instagram's explainer says. It lists the signal categories in the order Instagram gave them and the actions each surface tries to predict. Order reflects importance as the company described it in 2023.

Two patterns stand out. Your relationship with the poster appears on all four lists, so a follow graph is useful everywhere. And the weight of popularity rises as you move from feed to explore, because explore must rank accounts you have never met. Only signals Instagram has itself described are listed here, and nothing in the table implies a weighting formula, since Instagram does not publish one.

Controls, privacy and rules that shape the pool

A ranker orders a pool of posts. Before it runs, rules decide what is allowed into the pool. Instagram describes several that apply to everyone.

• Following and Favorites. A Following view shows posts from accounts you follow in the order they were posted, covering a recent period, and Favorites lets you choose accounts to see more of.
• Close Friends. A list you choose, used for stories shared with a smaller group.
• Mute, unfollow and snooze. Tools to reduce what you see from an account or pause suggested posts for a time.
• Not Interested, Sensitive Content Control and Hidden Words. Feedback and filters that shape recommendations and what appears in comments and messages.
• Recommendation guidelines. Posts that break them can be left out of explore, reels, search and suggested accounts, and creators can check their account status and appeal.

Privacy rules also shape the pool. A private account's posts are visible only to approved followers, and a blocked account cannot see you. For younger users, Meta has described stricter defaults under Teen Accounts, including private accounts and limits on who can contact them, and the European Commission's guidelines on minors recommend that recommender systems be adjusted to lower the risk of harmful content reaching children. We cover those duties in age verification for social media apps.

The design lesson is that privacy and ranking are not separate systems. A ranker that can see a private post and surface it to a stranger has failed, however good its predictions are. In our Instagram clone script, one database rule decides every visibility question, including private accounts, follows and blocks, and every surface asks the same rule before showing a post.

Designing the same split in your own app

You do not need Instagram's research to build a sensible version. The split between following and discovery is the useful idea, and you can build it in stages.

1. Launch with a following feed. Show posts from accounts a member follows, newest first, with privacy and block rules applied. It needs no model and members can understand it at once.
2. Add interest follows. Let members follow hashtags as well as people. This gives the feed interest signals that do not depend on who they know, which helps when they have few follows. Our product includes hashtag following.
3. Treat saves as a signal. A private save is a strong sign of interest because it costs the member something. Count saves, likes, comments and shares separately, and keep the counts per post so you can learn which matters.
4. Add a discovery tab. Once you have enough activity, a second surface that ranks posts by early engagement and a member's past activity serves explore's role. Keep it separate from the following feed so people always know where they are.
5. Add a short-video stream last. Reels style ranking needs watch time, completion and audio data. Collect those events from day one even if you do not use them yet.

Our platform supports the surfaces and the signals that feed them: follows, hashtag follows, likes, private saves, comments, reposts, close friends stories and an audio library. We also set up a trained recommendation model that ranks across them as tailored work, with the exact scope confirmed at kickoff via the contact page. The Instagram clone development cost page covers what drives the price. If your app has a small audience, a simple rule such as recent posts from followed accounts and followed tags beats a model with too little data to learn from. See the cold start discussion in the cold-start problem on a creator platform.

A worked example with invented numbers

The numbers below are an example, not data from any platform. Say a new cooking network has 2,000 members and one chef posts a carousel of a recipe. The chef has 300 followers.

• In the following feed, 300 followers are eligible. Say 180 of them open the app that day and 120 see the post, because it ranks below older posts from closer friends. Of those, 30 like it and 12 save it.
• In the discovery tab, the post enters a pool of recent posts. The system shows it to 200 members who follow cooking tags. Twenty save it. A save rate of 10 percent is high, so the post is shown to 600 more.
• Over the day the post reaches roughly 920 people, three times the chef's follower count, and the chef gains 25 new followers.

The structure is what matters. The following feed rewards the relationship the chef has already built. The discovery tab rewards the early reaction of strangers. A network with only the first surface grows slowly, and a network with only the second has no reason for anyone to follow.

What creators should take from it

If you post on Instagram, the explainer suggests a short list of habits, none of which is a trick.

• Make posts people finish, save or send. Reels count watch-through and reshares, and explore counts saves and shares.
• Answer comments and messages. Closeness and engagement history feed feed and stories ranking, so conversation builds reach with the people who already follow you.
• Use different formats for different jobs. A carousel suits followers who want depth. A reel suits finding new people.
• Stay inside the recommendation guidelines. Restricted accounts lose access to the surfaces that bring new followers.
• Check account status. Instagram gives creators a way to see whether they are eligible for recommendations and to appeal.

If you run the platform, the same list is a product brief: make saving, sharing and replying easy, make closeness visible, and give creators a status page and an appeal path.

What the explainer does not say

Search for this topic and you will find long lists of tricks: post at a certain hour, use a certain number of hashtags, avoid certain words. Instagram's explainer does not say any of that. It does not name hashtags as a ranking signal, it does not give a best posting time, and it does not publish a weighting. It says a post's timestamp is one input to feed, and that is all it says about timing.

That gap matters for two reasons. If you are a creator, advice that sounds precise but has no source is a guess, and the app itself changes often enough that a tip can expire in a season. If you are a builder, you are free of folklore: you can decide what your own ranker rewards, say so in your help center, and keep it stable. Members trust a feed whose rules they can predict.

A practical way to treat unverified advice is to test it on your own audience. Run a change for a few weeks, keep impressions and reach in the same dashboard, and compare. Our product includes thirty-day creator analytics covering impressions, engagement rate, reach and top content, which is enough to run that kind of check.

Operator checklist before you ship a feed

1. Write one sentence for each surface saying what it is for.
2. List the signals each surface may use, and the ones it must never use, such as private content.
3. Apply privacy, block and age rules before ranking, not after.
4. Give members a chronological or following-only option and a way to say Not Interested.
5. Record impressions, likes, saves, comments, shares and watch time per post.
6. Label suggested and promoted posts so members know why they see them.
7. Offer creators a status view and an appeal path for restricted posts.
8. Review the feed against your moderation rules, and read content moderation models for who should do what.

Glossary and pitfalls

• Ranking: ordering a pool of eligible posts by predicted value to one viewer.
• Candidate pool: the set of posts allowed to be shown before ranking begins.
• Signal: a piece of information used in a prediction, such as a save or a past reply.
• Follow graph: the record of who follows whom.
• Discovery surface: a feed that shows accounts you do not follow.

Three pitfalls come up often. Do not let one engagement number, such as likes, stand in for quality, since a ranker tuned to likes alone rewards the easiest content. Do not mix following and discovery in one feed without labels, because members lose trust when they cannot tell why they see a post. And do not build a model before you have data, since a rule you can explain is better than a model you cannot.

What to decide next

Pick your first surface and your first signals, and write down what the ranker may and may not show. For money, see how Instagram makes money, since ranking choices follow from the revenue lines you run. For the wider launch plan, read how to start a social media app. If your app leans toward short video, our TikTok clone guides cover a recommendation-first feed, and a ReelShort-style drama app shows a catalog-first feed that needs no ranking model at all. Instagram is a trademark of its owner, and GetFame is independent of it. This is an explainer for builders, and Instagram's own pages remain the authority for any detail you plan to rely on.