Your files never leave your device. All processing happens locally in your browser.
How do I preview what a Facebook post will look like before posting?
Paste your text into a client-side Facebook post preview tool and it renders a realistic feed card in real time: the page name and avatar, timestamp and audience icon, your text with Facebook’s real “… See more” fold and preserved line breaks, and a reactions / comments / shares bar. Switch the post type to Photo to attach an image, or to Link and fill in the URL, og:title, og:description and og:image to see the Open-Graph card — the uppercase domain, a two-line title and a one-line description over a 1.91:1 image — the way Facebook builds it from a page’s Open Graph tags. Toggle desktop vs mobile and light vs dark, watch the character count and fold indicator, then export the card as a PNG. Everything runs in your browser; nothing is uploaded and it does not post to Facebook.
Live feed card: name, avatar, timestamp, audience icon, text and reactions bar
Real “See more” fold (~477 chars desktop text-only, shorter with an attachment, ~125 on mobile)
Open-Graph link card: uppercase domain, 2-line title, 1-line description over a 1200×630 image
Enlarged font for very short text-only posts, plus Facebook’s colored status backgrounds
Desktop / mobile and light / dark, PNG export — 100% client-side, nothing uploaded
What is
Facebook Post Preview
A Facebook post preview (or post mockup) tool renders a draft as it would appear in the Facebook news feed — the page name and avatar, timestamp and audience icon, the body text, any attached photo or shared-link card, and the reactions bar — so you can check formatting before publishing. A faithful one reproduces Facebook’s real “… See more” truncation fold, the larger font it gives very short text-only posts, and the Open-Graph link card (uppercase domain, clamped title and description over a 1.91:1 image) that Facebook builds from a page’s og:title, og:description and og:image tags. It is a local design mockup: it does not fetch the URL, log in, or post to Facebook.
Social Media
Related terms
Open Graphog:imagelink previewSee more foldnews feedpost mockupSharing Debugger1200×630reactions bar
Frequently Asked Questions
No. Your text, links and any avatar / photo / link image stay in your browser as data URLs, and the tool never connects to Facebook — it only builds a local mockup.
The preview is 100% client-side. Your text and link fields are just strings in the page, and any avatar, photo or link image you pick is read with the browser’s FileReader into a data URL that never leaves your device — there is no upload, no server and no CDN in the processing path. The tool deliberately does not connect to Facebook: it cannot log in, fetch the URL you type, or publish anything, so it is a design mockup only. The PNG export is drawn from the on-screen card locally with html2canvas, the tool works offline once cached, and the only optional network use anywhere on the site is consent-gated ads that never see your content.
Roughly after 477 characters for a text-only post on desktop, sooner when a photo or link is attached, and around 125 characters on mobile — the tool folds your text the same way.
Facebook truncates long post text and hides the rest behind a “… See more” link. On desktop web a text-only post folds at about 477 characters; once a photo or link card is attached the fold is shorter (this tool uses ~280); and on mobile the feed folds much earlier, around 125 characters, so most posts get a “See more”. The tool applies that same threshold for your chosen device, backing up to a word boundary so no word is split, and shows a live indicator of whether — and where — your post folds, plus how many characters are hidden. Facebook also folds by line count and constantly A/B-tests the exact cutoff, so treat these as close approximations.
Choose a Link post and type the URL, og:title, og:description and og:image; the card shows the uppercase domain, a two-line title and one-line description over a 1200×630 image — the way Facebook scrapes a page.
When you share a URL, Facebook does not use your post text for the card — it scrapes the destination page’s Open Graph meta tags (og:title, og:description, og:image) and renders a card. This tool simulates that: switch the post type to Link and fill those fields in, and the preview renders the card exactly as Facebook lays it out — the domain in UPPERCASE, the title clamped to two lines, the description clamped to one line, over a 1.91:1 (1200×630) image you can upload. Because the tool is offline it cannot read the real tags for you, so you enter them by hand; to confirm what Facebook will actually pull for a live URL, run it through Facebook’s official Sharing Debugger.
Facebook enlarges the font of very short text-only posts and offers colored status backgrounds for short posts; the preview reproduces both, and reverts to normal once a post is long or has an attachment.
Facebook gives short text-only status updates a larger font so they stand out in the feed — the shorter the post, the bigger the type — and it also lets you put short text on a colored gradient background. Both treatments only apply to text-only posts up to roughly 130 characters and disappear the moment the post gets longer or you attach a photo or link. The tool mirrors this: it enlarges the font in tiers for short text, offers a set of colored backgrounds that unlock only for short posts, and drops back to the normal body size for long or attachment posts, with a badge telling you which tier is active. As always these are approximations of Facebook’s A/B-tested layout.
Detailed Explanation
📖How It Works
What the Facebook Post Preview Does
The tool renders a draft as it would appear in the Facebook news feed so you can check formatting before publishing. You type the post text and set the page name, avatar (upload or auto initials), verified tick, timestamp and audience, then pick a post type: Text, Photo, or an Open-Graph Link. The preview updates in real time as a feed card — header, body, any attachment, and a reactions / comments / shares bar — and you can switch between desktop and mobile widths and Facebook’s light and dark surfaces. It is a local design mockup: it does not connect to, log in to, or publish on Facebook.
Live feed-card render: header, body, attachment and reactions bar
Three post types: Text, Photo, and Open-Graph Link
Desktop / mobile widths and Facebook light / dark surfaces
A design mockup — it never posts to or connects to Facebook
⚙️Methodology
How the “See more” Fold Is Computed
A pure engine (facebookPostEngine.ts) reproduces Facebook’s truncation, with no network and no AI. It picks a character fold from the device and whether an attachment is present — about 477 characters for a text-only post on desktop, a shorter fold when a photo or link is attached, and around 125 characters on mobile — then, if the text is longer, it cuts at that fold but backs up to the nearest word or line boundary within a small window so no word is split, appending “… See more”. The same engine decides the font tier: very short text-only posts get the largest font, short ones a larger font, and anything long or with an attachment the normal body size, mirroring how Facebook enlarges brief status updates. It also uppercases the link domain and formats engagement counts as “1.2K”.
Fold thresholds: ~477 desktop text-only, shorter with an attachment, ~125 mobile
Cuts at a word / line boundary so no word is split, then appends “… See more”
Font tier: largest for very short text-only, larger for short, normal otherwise
Domain uppercased; counts formatted as 1.2K / 3.4M
🔧Technical Details
The Open-Graph Link Card
When a URL is shared, Facebook ignores the post text for the card and instead scrapes the destination page’s Open Graph meta tags — og:title, og:description and og:image — and renders a link card. This tool simulates that card: in a Link post you enter those fields by hand and the preview lays them out the way Facebook does, with the domain in UPPERCASE (www stripped), the title clamped to two lines, the description clamped to one line, over an image at Facebook’s recommended 1200×630 (1.91:1) size. Because the tool runs offline it cannot read the real tags for a live URL; to confirm exactly what Facebook will pull, run the URL through Facebook’s official Sharing Debugger, which also lets you re-scrape after you change the tags.
Facebook builds link cards from og:title, og:description and og:image
Verify a live URL with Facebook’s Sharing Debugger
⚠️Limitations
Honest Limitations
This is an approximation of Facebook’s current web feed, not a pixel-perfect replica. Facebook constantly A/B-tests its layout, so the exact “See more” cutoff, the enlarged-font threshold, colored-background availability and card widths vary by device, viewport, language and account, and the mobile apps differ from the web again. The tool does not fetch or verify the URL you type — you supply the Open Graph fields yourself — and system fonts stand in for Facebook’s Helvetica/Segoe, so wrapping and truncation are close but not identical. It creates mockups for design, planning and approvals; it cannot log in, schedule, or post to Facebook, and it does not generate copy. Always spot-check the real thing (and, for links, the Sharing Debugger) before a launch.
Approximation of an A/B-tested layout — exact fold and widths vary
Does not fetch the URL; you enter og:title / og:description / og:image
System fonts substitute for Helvetica/Segoe, so wrapping differs slightly
A mockup only — no login, scheduling or posting
🔒Privacy & Security
Private by Design
Everything — the fold, the font tier, the uppercase domain, the counts and the card layout — runs on your device in JavaScript. Your text and link fields are only strings in the page, and any avatar, photo or link image you choose is read with the browser’s FileReader into a data URL that never leaves your device; there is no upload, no backend and no CDN in the processing path. The PNG export is drawn from the on-screen card locally with html2canvas. There is no account, database, analytics or telemetry, the tool works offline once cached, and closing the tab discards your work. The only optional network use anywhere on the site is consent-gated advertising, which never sees your content.
All rendering and computation run locally in the browser
Images are local data URLs — nothing uploaded, no backend, no CDN
PNG export generated in-browser with html2canvas
Works offline once cached; only optional network use is consent-gated ads
Approximate Facebook feed behaviour by device and attachment (A/B-tested; verify live)
Situation
Approx. “See more” fold
Font treatment
Text-only post, desktop web
~477 characters
Larger for short (≤130), else normal
Post with photo or link, desktop
Shorter (~280 characters)
Normal body size
Any post on mobile feed
~125 characters
Normal body size
Very short text-only status
No fold
Largest font (and colored background option)
Facebook also folds by line count and A/B-tests the exact cutoff, so these are close approximations, not guarantees. Mobile apps differ from the web again.
