PrepMyPost
Our own product: 50+ creator tools where the photo never leaves the phone.
THE STORY
Five tabs for one client photo
A normal day on social accounts meant taking one client photo through five websites: one to resize it, one to remove the background, one to count the caption, one for the PDF, one for the QR code. Most of them uploaded the file to their own server before doing anything, some added a watermark, and the good ones wanted an account. Client photos, ID scans for form uploads, invoices with bank details: all of it passed through servers we knew nothing about. That was the brief we wrote for ourselves.
Nothing leaves the browser
Every tool loads into the visitor's browser and does the work on their device. The site is static: there is no upload endpoint to send a file to, so the privacy promise is enforced by the architecture, not by a policy page. The one exception is honest about itself: the domain and username checker sends the typed name from the browser straight to the public registries, never to us. A side effect we planned for: the AI models are served as ordinary static files in parts under 25 MB, so a bot hammering the site cannot run up a compute bill.
Background removal on a mid-range phone
A full-quality cut-out model is heavy, and the visitor's device is the server. We plan the model per device: half-precision on WebGPU where the graphics card supports it, full precision on WebGPU where it does not, and the CPU as the last resort. Testing taught us the expensive lesson: on a weak GPU without half-precision support the full model ran for more than three minutes, and Chrome then disabled WebGPU on that machine entirely. Those devices now get a fast, lighter model by default, with the full model on the CPU one tap away. To make that CPU path fit, we rebuilt the model's heaviest layers to run one slice at a time: peak memory fell from 3.3 GB to 1.5 GB with an identical mask. Shipping the weights as 8-bit integers kept masks 99.98% identical on product photos.
What it does not do
The high-definition cut-out on the CPU takes 45 to 50 seconds on a four-core laptop. That is slower than a server, and it is the price of never receiving the photo. Offline use works after the first run, because the AI model has to download once. And a free, ad-funded site lives or dies on search, which takes months: the content is built for it, the traffic is not there yet.
Numbers when they are real
PrepMyPost went live in October 2026 with a Product Hunt launch scheduled for the same month. We are not putting traffic figures on this page until they exist. What we can show today is the build itself: open a photo tool, switch on airplane mode after it loads, and it keeps working.
THE WORK
PrepMyPost is the toolbox we wanted on client work and could not find: resize one photo for every platform, cut out a background at full resolution, make the post, count the caption, build the invoice. Every free site we used uploaded the file first, stamped a watermark or asked for an account. So we built one where all of it runs in the visitor's browser, including the AI. Free, funded by ads, live since October 2026.
RESULTS
// FOR BUSINESSES LIKE YOURS
Could a free tool be your best marketing page?
A useful tool earns links, mentions and repeat visits that a services page never will. We build them for our own work and for clients: calculators, generators and file tools that run in the browser, cost almost nothing to host and keep the user's data on their device.
- →Browser-based tools with no backend to run or secure
- →On-device AI where the data is sensitive
- →One page per search phrase, built for SEO from day one
- →Hosting that stays near zero as traffic grows
COMMON QUESTIONS4 questions answered
Is PrepMyPost a client project?
No. It is our own product, built and run by Fourlines. That is why we can publish the engineering details here: the memory numbers, the failures and the trade-offs are ours to share.
How can an AI background remover work without uploading the photo?
The model is downloaded to the browser once and runs on the visitor's device, using the graphics card through WebGPU or the CPU through WebAssembly. The photo is processed in memory on the device; the site has no endpoint that could receive it.
What does it cost to host?
Very little. The site is static files on Cloudflare, including the AI models, so there are no servers doing the work and no per-request compute bill. The visitor's device does the processing.
Can you build a tool like this for my brand?
Yes. Browser-based tools are one of the most durable ways to earn search traffic and links. We scope them the same way: what runs on the device, what (if anything) needs a server, and which search phrases each page answers.