Shahrukh Khan says he built 272 browser-based tools that process files on the user’s device instead of uploading them to a server. His account describes a practical trade-off: local processing can reduce exposure of file contents to a service, but it also makes performance depend on the browser and device. The project count and technical details below are Khan’s claims, not independently verified measurements or a security audit. Read Khan’s article on DEV Community.
What “no backend” means for file processing
Khan says he began with a PDF compressor after finding that many free online compressors appeared to follow an upload-process-download pattern. That is his characterization, not a verified survey of competing services. His alternative is to run the operation in the browser: the page loads its code and processing library, then works with the selected file on the user’s device.
As an Amazon Associate I earn from qualifying purchases.
That changes the trust question. If an operation genuinely stays on-device, the service does not need to receive the file in order to process it, and the user need not rely on a server’s file-deletion promise for that operation. It does not, by itself, prove that a particular website never transmits file data or that its code is secure. Khan’s statement, “You don’t have to trust anything if the file never leaves your machine,” expresses the architectural goal; it is not evidence that every tool’s network behavior has been audited.
The Tool Desk
Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Outbyte Driver Updater FREEFix the driver behind crashes, sound loss and screen glitchesFind Drivers →What Khan says he built
Khan reports that the resulting Toolspace contains 272 tools across PDFs, images, video, audio, converters, calculators, writing, and developer utilities. That is the count and categorization in his September 29, 2026 article, not a current independently checked inventory.
#1 Best Overall
- [2 Pack] This product includes 2 pack privacy screen protectors.WORKS FOR iPhone 17e/16e/14/iPhone 13/13 Pro 6.1 Inch tempered glass screen protector.Featuring maximum protection from scratches, scrapes, and bumps.[Not for iPhone 16 6.1 inch, iPhone 13 mini 5.4 inch, iPhone 13 Pro Max/iPhone 14 Pro Max/iPhone 14 Plus 6.7 inch, iPhone 14 Pro 6.1 inch]
- Specialty: to enhance compatibility with most cases, the Tempered glass does not cover the entire screen. HD ultra-clear rounded glass for iPhone 17e/16e/14/iPhone 13/13 Pro is 99.99% touch-screen accurate.
- 99.99% High-definition clear hydrophobic and oleophobic screen coating protects against sweat and oil residue from fingerprints.
- High Privacy: Keeps your personal, private, and sensitive information hidden from strangers,screen is only visible to persons directly in front of screen.Good choose when you are in the bus,elevator,metro or other public occasions.(Note: Due to this privacy cover will darken the image to prevent the peeking eyes near you, you might need to turn your device display brightness up a bit when use it.)
- Online video installation instruction: Easiest Installation - removing dust and aligning it properly before actual installation,enjoy your screen as if it wasn't there.
The described architecture combines static pages with browser APIs and JavaScript or WebAssembly libraries. Khan names Next.js 16 static export, Web Workers for heavy operations, and a service worker to cache WebAssembly binaries after the first load. The specific processing components he lists are:
- Video and audio: ffmpeg.wasm.
- PDF creation and editing: pdf-lib.
- PDF rendering: pdf.js.
- HEIC image decoding: libheif-js.
- Image operations: Canvas API and OffscreenCanvas.
These are implementation details reported by the author; they are not the result of an independent inspection of the live service or its source code.
Rank #2
- Perfect Fit for iPhone 17 Pro Max：Engineered exclusively for iPhone 17 Pro Max with seamless edge-to-edge coverage, ensuring precise alignment and reliable full-screen protection.
- Advanced Privacy Protection：Features a 28° privacy filter with smooth 2.5D curved edges, preventing side glances in public. Your screen remains visible only to you—ideal for commuting, traveling, and crowded environments.
- Effortless Installation：Equipped with an auto dust-elimination tool that delivers a fast, accurate, and bubble-free application, keeping your screen perfectly clear with minimal effort.
- Military-Grade Protection：Made of nano-reinforced 9H tempered glass, SGS certified. Provides 5X stronger scratch resistance and proven durability, withstanding thousands of pressure and impact tests.
- Smudge & Fingerprint Resistant：Hydrophobic and oleophobic coating repels fingerprints, sweat, and oil—ensuring your screen stays clean, clear, and smooth to the touch.
How the file operations work
HEIC to JPG with ffmpeg.wasm
In the example, the browser loads an FFmpeg instance once and reuses it rather than initializing the runtime for every conversion. The selected file is written into FFmpeg’s in-memory virtual filesystem, the conversion runs, and the resulting bytes are read back for download. The code then removes the temporary input and output entries from that virtual filesystem.
This illustrates an important implementation detail: “local” processing still creates temporary working data in browser memory. Reusing the initialized runtime can avoid repeated setup, while cleaning up temporary files helps release resources after a job. Khan’s example describes the code’s intended flow; it does not establish a tested performance result.
Rank #3
- [3 Pack] This product includes 3 pack privacy screen protectors.WORKS FOR iPhone 16/iPhone 15/iPhone 15 Pro 6.1 Inch tempered glass screen protector. Due to the rounded edge design of the iPhone 16/iPhone 15/iPhone 15 Pro and to enhance compatibility with most cases,the tempered glass screen protectors will be slightly smaller than the phone screen.[Not for iPhone 16e 6.1 inch, iPhone 15 Plus/iPhone 15 Pro Max/iPhone 16 Plus 6.7 inch,iPhone 16 Pro 6.3 inch,iPhone 16 Pro Max 6.9 inch]
- Specialty: HD rounded glass for iPhone 16/iPhone 15/iPhone 15 Pro 6.1 Inch is 99.99% touch-screen accurate.
- 99.99% High-definition hydrophobic and oleophobic screen coating protects against sweat and oil residue from fingerprints. Featuring maximum protection from scratches, scrapes, and bumps.
- High Privacy: Keeps your personal, private, and sensitive information hidden from strangers,screen is only visible to persons directly in front of screen.Good choose when you are in the bus,elevator,metro or other public occasions.(Note: Due to this privacy cover will darken the image to prevent the peeking eyes near you, you might need to turn your device display brightness up a bit when use it.)
- Online video installation instruction: Easiest Installation - removing dust and aligning it properly before actual installation,enjoy your screen as if it wasn't there.
Merge PDFs with pdf-lib
For PDF merging, the described approach loads each input document, copies its pages into a new document, and saves the combined file. Khan notes that password-protected PDFs should fail clearly rather than yield silently broken output. That is a useful error-handling requirement for a browser utility, not a claim that every encrypted PDF format or password case is supported.
What determines speed and compatibility
WebAssembly makes it possible to run compiled processing code in a browser, but it does not remove the browser’s memory, CPU, or platform constraints. Web Workers can keep a long operation from blocking the page’s main thread; they do not make the work cost-free.
Rank #4
- [3+3 Pack] This product includes 3 pack privacy screen protectors and 3 pack camera lens protectors with Installation Frame. Works For iPhone 16 [6.1 inch] tempered glass screen protector and camera lens protector. Featuring maximum protection from scratches, scrapes, and bumps. [Not for iPhone 16e 6.1 inch, iPhone 16 Pro 6.3 inch, iPhone 16 Pro Max 6.9 inch, iPhone 16 Plus 6.7 inch]
- Night shooting function: specially designed iPhone 16 6.1 Inch camera lens protective film. The camera lens protector adopts the new technology of "seamless" integration of augmented reality, with light transmittance and night shooting function, without the need to design the flash hole position, when the flash is turned on at night, the original quality of photos and videos can be restored.
- High Privacy: Keeps your personal, private, and sensitive information hidden from strangers, screen is only visible to persons directly in front of screen. Good choose when you are in the bus,elevator,metro or other public occasions. (Note: Due to this privacy cover will darken the image to prevent the peeking eyes near you, you might need to turn your device display brightness up a bit when use it.)
- Easiest Installation - Please watch our installation video tutorial before installation. Removing dust and aligning it properly with the help of the included installation frame before actual installation, enjoy your screen as if it wasn't there.
- 99.99% High-definition clear hydrophobic and oleophobic screen coating protects against sweat and oil residue from fingerprints, and enhance the visibility of the screen.
For multithreaded FFmpeg, Khan says his implementation requires cross-origin isolation so the browser can expose SharedArrayBuffer. The headers he identifies are Cross-Origin-Opener-Policy: same-origin and Cross-Origin-Embedder-Policy: require-corp. He says the implementation falls back to single-threaded processing when those conditions are unavailable. Some embedded in-app browsers may not support SharedArrayBuffer, so their behavior can differ from a fully supported desktop browser.
What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
Costs and constraints of local processing
- Memory: The author gives approximately 500 MB as an example of browser memory on a “decent desktop” and says iOS Safari caps lower. He provides no reproducible test setup, so this is an illustrative estimate, not a reliable limit for every browser or device.
- First load: Khan estimates the multithreaded ffmpeg.wasm build at about 30 MB gzipped and reports a 3–8 second first visit to a video tool. These are his approximate figures, without a stated measurement method or device and connection details. A service worker is described as caching Wasm binaries after the first load, which can reduce the need to fetch them again, but does not eliminate the initial download.
- Device load: Large conversions can consume phone battery and generate heat, according to Khan. Local computation shifts the workload to the user’s device rather than making the workload disappear.
- Browser support: Missing SharedArrayBuffer support can mean a slower single-threaded path, and some in-app webviews may not expose the required capability.
When a browser-side tool is a good fit
Local processing is especially useful when the task can be completed in the browser and keeping file contents off a processing server is a priority. Whether a particular tool is appropriate still depends on the actual site implementation, the file size, the browser, and the operation.
Best Value
- 【Industry-Leading 100% Anti-Spy Privacy Protection】Designed for iPhone 17 Pro Max. Larger iPhone screens are easier for others to glance at, so UltraGlass uses patented, SEGI-certified 25° Blackout-3 optical technology to help block side views and keep emails, banking apps, and private content visible only to you—while keeping the front view HD-clear and comfortable through hours of scrolling and streaming.
- 【Unbreakable TOP 9H+ Glass, the Excellent 2nd Screen for Your iPhone】Boasting unparalleled shatter resistance and durability. And the core excellence is the top 9H+ tempered glass material, which is widely applied in aerospace and military fields for its ① Shatter-proof ② Scratch & Wear Resistance ③ Durability that is 7-8 times higher than other materials. Thus, UltraGlass builds a second tough screen for your iPhone 17 Pro Max.
- 【Invisible Armor, 1:1 Full Covers the iPhone's Screen】Mimicking the iPhone's original screen design, it uses a 1:1 3D curved reinforced black edge that wraps around every curve — case friendly — while securing even the most vulnerable edges. Seamlessly blending with the iPhone 17 ProMax screen, it's virtually invisible and feels like the original screen while offering enhanced full-screen protection.
- 【0 Bubbles + 0 Dust + 0 Misaligned =100% Successful Installation】Includes everything you need with pioneering automatic positioning, dust removal, and absorption technology, making the installation just effortlessly easy in seconds. No bubbles, no troubles—transforming beginners into experts!
- Trusted Quality, Lifetime Support】Trusted by millions worldwide, UltraGlass comes with a Lifetime Warranty covering installation, fit, and accidental damage. Our 24/7 support team is ready to help with fast, 1-on-1 assistance.
| Consideration | Browser-side processing | Server-side processing |
|---|---|---|
| Where file contents are handled | Can remain on the device if the implementation does not transmit them; verify the specific tool. | Must reach the server for server-side processing; retention practices vary by service. |
| Memory and practical file size | Bounded by browser and device resources. | Depends on the service’s infrastructure and limits; Khan’s article does not quantify them. |
| Initial loading | May require downloading large libraries, especially for media tools. | Processing code and capacity are hosted by the service; no general load-time comparison is established. |
| Compute and energy | Uses the user’s CPU and can affect battery and heat on mobile devices. | Uses the service’s compute resources; the article gives no comparative cost figures. |
The table compares architectural trade-offs, not a ranking of products. Neither “browser-based” nor “server-based” alone establishes a service’s privacy or security. For sensitive files, check what the specific page says it uploads and, where that matters, inspect its actual network behavior rather than relying only on a privacy label.
What the project demonstrates—and what it does not
Khan’s account is a useful example of how WebAssembly, browser APIs, and JavaScript libraries can support a broad set of file utilities without making server-side file processing the default. It also shows why a privacy-oriented design has engineering costs: large runtimes must be downloaded, browser memory is finite, threading support varies, and the user’s device performs the work.
The article does not establish the live project’s current tool count or availability, provide a reproducible benchmark for its performance estimates, or independently verify that all file operations remain local. Treat the reported architecture and figures as the author’s description, not as a guarantee about the site or a general benchmark for browser tools.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
