Add Digital Signatures to PDFs Online Sign PDF with signature.
PDF Sign
Sign PDF with signature.
Upload PDF
Select or drop your PDF file.
Configure signature
Choose draw, type, or image mode and set position.
Download signed PDF
Save or share the signed file.
What Is PDF Sign?
A PDF Sign is a digital tool that enables users to electronically sign PDF documents using various methods such as drawing, typing, or uploading an image of their signature. It is commonly used by individuals and businesses that need to add signatures to contracts, agreements, and other official documents in pdf format. One specific problem it solves is the hassle of printing, signing, and scanning documents, which can be time-consuming and inefficient, especially when trying to figure out how to sign pdf online.
The tool's target audience includes professionals who frequently work with pdf files and need a convenient way to add their signature, such as freelancers, entrepreneurs, and remote workers. It is particularly useful for those who want to sign pdf documents online without having to install any software or pay for expensive services, essentially getting a free pdf sign experience.
What sets this tool apart from others is its ability to allow users to customize the placement of their signature on the PDF document, with options to position it at the bottom-right, bottom-left, or center of the page, making it easy to add signature to pdf free. Additionally, it provides features like font style selection for typed signatures and image upload for custom signatures, allowing users to personalize their pdf sign experience. The tool's client-side implementation ensures that all processing is done locally in the browser, eliminating the need to upload sensitive documents to external servers, which is a key benefit when looking for a way to sign pdf online securely.
Why Use PDF Sign?
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Visual pdf sign interface
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Client-side
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Free
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One-click copy
Common Use Cases
Development
Sign NDAs and contracts during development.
Review
Validate and review signed documents.
Docs
Sign configuration and specification documents.
Learning
Explore signature workflows interactively.
Technical Guide
The tool works under the hood by utilizing client-side JavaScript with React, where memoization is used to optimize performance through functions like `useCallback` and `useRef`. When a user selects a PDF file, it is loaded into memory using the `pdf-lib` library, which allows for the extraction of page count and other document properties. The `arrayBuffer` method is then used to convert the file into an array buffer, enabling further processing. For drawing signatures, the tool employs HTML5 canvas elements, where mouse and touch events are captured and translated into canvas coordinates using functions like `getCanvasPoint`. This allows for smooth rendering of the signature on the canvas.
The `computePosition` function calculates the placement of the signature based on user-selected options, such as position and page target. It takes into account the dimensions of the PDF page, signature width, and height to determine the optimal coordinates for rendering the signature. The tool also utilizes browser APIs like the Clipboard API to handle image uploads and other tasks. For typed signatures, it uses HTML canvas elements in conjunction with font styles selected from predefined options, including cursive, serif, and sans-serif. Responsive UI is achieved through React components, ensuring a seamless user experience across various devices and screen sizes.
In terms of data structures, the tool relies heavily on JavaScript objects to store state variables like `file`, `pageCount`, `processing`, and `result`. These objects are updated dynamically as the user interacts with the tool, enabling real-time rendering of signatures and other visual elements. The use of React hooks like `useState` and `useEffect` allows for efficient management of these state variables, ensuring that the UI remains up-to-date and responsive throughout the signing process. By leveraging these technologies and data structures, the tool provides a robust and user-friendly solution for electronically signing PDF documents.
Tips & Best Practices
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1Configure target pages by setting `targetPage` to 'last', 'first', or 'all'
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2Set custom font styles for typed signatures using `FONT_STYLE_OPTIONS`
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3Adjust signature placement using the `computePosition` function
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4Clear drawn signatures by calling `clearDrawCanvas`
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5Start drawing signatures at specific points with `startDraw` and `getCanvasPoint` functions
Related Tools
Frequently Asked Questions
Q Is the PDF sign tool free?
Q Is it safe to sign PDFs online?
Q Can I sign PDFs offline?
Q Which browsers support PDF signing?
Q Can I use it for commercial documents?
About This Tool
PDF Sign is a free online tool by FreeToolkit.ai. All processing happens directly in your browser — your data never leaves your device. No registration or installation required.