DEJA is a free Chrome browser extension that detects duplicate and near-duplicate posts on LinkedIn and X (Twitter). It marks posts you've already seen, paraphrased echoes, and engagement-template spam using local fingerprints on your device.

Does DEJA work on LinkedIn and Twitter?

Yes. DEJA runs on LinkedIn feeds and X (Twitter) feeds. It only scans feed-like pages—not your profile sections—and shows quiet marks for seen posts, echoes, and patterns.

Yes by default. Fingerprints stay in chrome.storage.local on your device. There is no DEJA server and no account. Optional AI mode only sends short text snippets to an embeddings API you configure.

Yes. DEJA is free. The local duplicate filter works offline with no subscription required.

How does DEJA detect duplicate posts?

DEJA uses a cascade: normalized exact hashes, 64-bit simhash near-duplicate detection, token Jaccard overlap for paraphrases, and structural template matching for engagement-bait patterns. Optional embeddings can improve semantic matching if you add your own API key.

deja

You've seen this post before.

Free Chrome extension that detects duplicate LinkedIn posts and X (Twitter) spam templates. DEJA remembers what already scrolled past you — and quietly marks the echoes.

Local by default · No account · LinkedIn & X feed filter

Scroll

M. Alvarez seen · 3d ago

I turned down a $500K offer to stay at a startup. Here's why loyalty beats money every time...

Fig. 01 — exact repost on LinkedIn

R. Okafor echo · 82%

Unpopular opinion: hustle culture is dead. Here's what actually works in 2026...

Fig. 02 — paraphrased duplicate

T. Nakamura pattern · 4×

I rejected 3 job offers to build my own company. Everyone said I was crazy...

Fig. 03 — engagement template spam

The feed repeats itself

Every feed is the same three posts wearing different names. DEJA remembers, so you don't have to.

0 Bits per fingerprint

0 Minute age gate — no "just now" noise

0 Servers involved by default

The three marks

How DEJA labels LinkedIn & X spam.

seen

Same text, local memory

Detects exact or near-exact duplicate LinkedIn posts and X posts already in your on-device history.

echo

Near-duplicate, paraphrased

Same idea, reworded. Simhash + token overlap catch paraphrase spam without calling a server.

pattern

A template repeating

Flags engagement-bait template families that dominate LinkedIn and X feeds.

How it works

A cascade, not a guess.

[ 01 · Exact ]

Normalized hash match. Links, mentions, and hashtags stripped before comparing — catches straight reposts instantly.

[ 02 · Simhash ]

64-bit near-duplicate detection. Character trigrams and word bigrams, compared by Hamming distance.

[ 03 · Jaccard ]

Token overlap, paraphrase-aware. Catches reworded posts that simhash alone would miss — no AI required.

[ 04 · Template ]

Structural skeleton matching. Opener, closer, length band, and rhythm — flags engagement-bait families.

FAQ

Questions people ask about DEJA.

[ What ]

What is DEJA? A free Chrome extension that filters duplicate and near-duplicate posts on LinkedIn and X. It marks posts you've already seen, paraphrased echoes, and spam templates.

[ Where ]

Does it work on LinkedIn and Twitter/X? Yes. DEJA runs on LinkedIn and X feeds. It ignores profile pages (experience, honors, interests) and focuses on feed posts.

[ Privacy ]

Is my browsing data private? Local mode never leaves your device. No DEJA servers, no account. Optional AI embeddings only if you paste your own API key.

[ Price ]

Is DEJA free? Yes. The core duplicate filter is free and works offline.

Local by default

Your feed history stays on your device.

DEJA's free path runs entirely offline — fingerprints are computed and stored in chrome.storage.local, and nothing about what you read ever leaves your browser. Optional AI mode sends short snippets only to an embeddings endpoint you configure. Read the full privacy policy for the DEJA Chrome extension.

No account, no sign-in
No DEJA servers — there are none
No selling or sharing browsing data
Clear memory anytime from the popup

Stop reading the same LinkedIn post twice.

Free Chrome extension for LinkedIn & X. Local by default.

Get DEJA on GitHub [ Load unpacked from the repo · Chrome Web Store link after approval ]