// about
About jakup
jakup is a free site where you make something in your browser and leave with a file — no install, no sign-in. Stamp or sign a PDF, make a seal or signature image, fit a photo to passport size, redact an ID copy, or print a certificate: the kind of job that ends with a file in your hands. There are calculators too, but on jakup a calculation is an ingredient; the result is a file.
The name says it. In Korean, jakup (작업) means "work" — the act of making something, and jakup is built so that the making finishes inside your browser.
What you can make
Grouped by what you take away when you are done:
- Stamping and signing documents — Sign and Stamp PDF, Seal & Stamp Maker (round or square seals as transparent PNG), Signature Maker, Company Nameplate Stamp. You can make a seal and place it on a PDF without leaving the site.
- Photos and documents — ID & Passport Photo Maker, Image Redaction for ID copies and screenshots, Certificate Maker.
- Codes and images — QR codes, barcodes, favicons, and image cropping, resizing and format conversion (including HEIC to JPG).
- Keeping your own data and coming back — the Stock Averaging Calculator remembers your positions in your browser, so next time you only update the prices.
- Getting an answer — random numbers, compound interest, date and D-day, character counting, and a handful of developer tools.
jakup started as a Korean site, and some tools are built around Korean paperwork and rules — pay slips, Korean salary take-home, the lunar calendar. Those are offered in Korean only, so they do not appear in the English list. Everything on the English home page works fully in English.
How it differs from a calculator site
There are plenty of sites that hand you a number. What jakup aims for is a result you can take with you: a seal becomes a transparent PNG, a stamped contract becomes a PDF, a certificate becomes something you can print. When we choose what to build next, we favour jobs that end with a file.
Those files are usually things you would rather not upload to someone else's server — contracts, ID copies, signatures. So jakup does this work entirely in your browser, and the files never travel to a server in the first place. That is also why many tools keep working after the page has loaded, even offline.
Why we built it
The web already has tools that do these jobs, but many are buried under ads, or quietly send what you type to a server. When the file is a seal or an ID card, "where does this go?" matters, and the answer is rarely clear. jakup tries to be light, fast, and clear about where your data goes — which is nowhere.
How we run it
- Processed in your browser — making seals and signatures, stamping PDFs, editing images and counting text all happen on your device. Files and inputs are not sent anywhere.
- Minimal personal data — no account is needed to use any tool. Sign-up is only used for the request board, and asks for no more than an email address.
- State the basis, avoid overclaiming — where a value depends on rules or standards, we say which ones. Where the answer depends on the document (for example, whether an image seal is accepted), we say so instead of promising.
- Free, supported by ads — running costs are covered by advertising, which is what lets every tool stay free.
Who runs jakup
jakup is planned, built and run by the jakup team (작업닷컴 운영팀). For questions or suggestions, write to jakup@jakup.com or see the contact page. Mail in English is welcome.
What comes next
New tools keep arriving. If there is a tool you need that does not exist yet, or something you would like improved, leave it on the request board — user requests are the main input when we decide what to build next.