100% Client-Side Privacy — Zero Cloud Uploads

Fresh, Fast Utility Tools Inside Your Browser

Compress WebP/AVIF photos, craft CSS/SVG mesh backgrounds, format & diff JSON, preview OpenGraph cards, and calculate freelance fees — instantly in local RAM. Easy peasy.

Ctrl+K

⚡Runs 100% on Your Device CPU/GPU

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My Pinned Shelf & Local Cache

Click the star icon (★) on any tool card to pin it here for instant access.

All Browser Utilities

5 tools

Select a tool below — every utility executes locally in browser memory with zero server uploads.

Images100% Client-Side

Privacy Image Converter & Compressor

Convert and compress images directly inside your browser. Support for WebP, JPEG, PNG, and AVIF with zero file uploads.

Multi-image drag and drop batch processing
Format conversion: WebP, JPEG, PNG, AVIF
Custom quality control and image scaling

Open Image Converter

DesignInstant Export

CSS & SVG Visual Background Generator

Design modern mesh gradients, layered SVG waves, and frosted glassmorphism cards. Copy CSS, Tailwind, or export SVG and PNG.

Multi-stop fluid Mesh Gradient creator
Customizable layered SVG waves with curvature controls
Glassmorphism styler with blur and border opacity sliders

Open Background Studio

DeveloperAuto-Repair

Smart JSON Formatter & Diff Checker

Format, beautify, minify, sort, and auto-repair broken JSON. Compare two JSON or text payloads side-by-side with line diffing.

Auto-fixes trailing commas, single quotes, and unquoted keys
Beautify (2-space, 4-space), minify, and recursive key sorting
Side-by-side visual diff checker with additions and removals

Open JSON Formatter & Diff

SEO & SocialPixel-Perfect

OpenGraph & Social Card Live Previewer

Preview exact social cards across Google Search, X (Twitter), Facebook, LinkedIn, and Discord before publishing. Copy meta tags in 1 click.

Live Google Search SERP preview (Desktop & Mobile)
X / Twitter Large Summary Card simulation
Facebook and LinkedIn post card rendering

Open OpenGraph Previewer

FinanceMulti-Gateway

Freelance & Payment Fee Calculator

Calculate payment processor fees and discover exactly how much to invoice clients to receive your desired take-home payout.

Dual modes: Calculate Net Payout vs Calculate Required Invoice Amount
Side-by-side gateway comparison: Stripe, PayPal, Wise, and Custom Rates
Reverse fee formula: (Net + FixedFee) / (1 - Rate) for exact take-home target

Open Fee Calculator

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Zero Server Uploads

Files are processed in local volatile RAM via HTML5 Canvas and WebAssembly. No server ever sees your data.

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Instant Native Speed

Skip upload and download queues. Convert dozens of high-res photos in seconds right on your CPU/GPU.

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Local Result Cache

Save and restore your last tool output directly from browser storage — zero accounts or cloud lock-in.

Frequently Asked Questions

How does SwiftLemon process my files without uploading them?

SwiftLemon uses modern HTML5 Web APIs (Canvas, OffscreenCanvas, and WebAssembly) that execute entirely inside your device's web browser. When you select or drag a file, the data is loaded into your browser's local volatile RAM and transformed on your GPU/CPU. Zero file packets are ever sent over the network to any server.

How does the Local Result Cache work?

Whenever you copy, export, or click "Save Result to Cache" in any tool, SwiftLemon stores a snapshot of your latest output directly in your browser's localStorage. You can restore or copy your last result anytime with 1 click.

Are SwiftLemon tools 100% free to use?

Yes! Every SwiftLemon utility is 100% free with no account creation, watermarks, or daily file caps.

How do I pin my favorite tools to My Shelf?

Click the star icon (★) on any tool card or tool page. Your bookmarks are saved privately in your browser's local storage for 1-click access.