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assertpy VS OnlineGridMaker

Compare assertpy VS OnlineGridMaker and see what are their differences

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assertpy logo assertpy

A straightforward assertion library for Python.

OnlineGridMaker logo OnlineGridMaker

Add a precise grid overlay to any image for drawing and sketching. Customize rows, columns, line color and thickness. 100% free, no signup, no upload.
  • assertpy Landing page
    Landing page //
    2022-11-06
  • OnlineGridMaker
    Image date //
    2026-05-17

OnlineGridMaker is a free browser-based tool that adds customizable grid overlays to any image โ€” designed specifically for artists, illustrators, art students, and anyone who practices drawing from reference photos.

Why OnlineGridMaker?

Most grid tools are either too basic (fixed grid size, no customization) or require downloading desktop software. OnlineGridMaker runs entirely in your browser โ€” no install, no signup, no image uploads. Your photos stay on your device.

Key Features

Grid Overlay โ€” Add precise grids to any image with full control over rows, columns, line color, line thickness, and opacity.

Perspective Guides โ€” Built-in 1-point and 2-point perspective tools for accurate architectural and object drawing.

Cell Labels โ€” Optional row/column numbering for easy reference when transferring your sketch to paper or canvas.

Instant Download โ€” Export your gridded image as PNG or JPG and start drawing right away.

100% Local Processing โ€” All rendering happens in your browser using HTML5 Canvas. Your images are never uploaded to any server.

Perfect For

  • Art students learning proportion and scale
  • Illustrators working from photo references
  • Comic artists and storyboarders
  • Hobbyists practicing portrait or still life drawing
  • Art teachers demonstrating grid method techniques

Pricing

Completely free. No premium version. No signup required. Unlimited use.

assertpy

Website
github.com
$ Details
-
Platforms
-
Release Date
-
Categories

OnlineGridMaker

$ Details
free
Platforms
Web
Release Date
2026 May
Startup details
Country
China
Founder(s)
kaixiang liang
Employees
1 - 9

assertpy features and specs

  • Fluent API
    Assertpy offers a fluent API that makes assertions more readable and expressive, enabling developers to write assertions in a natural language style that is easy to understand.
  • Chainable Assertions
    It allows for chainable assertions, enabling multiple checks to be performed in a single line of code, thereby reducing verbosity and enhancing clarity.
  • Comprehensive Assertion Methods
    The library provides a wide range of built-in assertion methods, catering to various types of data validations, such as checking for size, type, value, and more.
  • Extensibility
    Assertpy supports extending its functionality by defining custom assertions, allowing developers to tailor it to their specific needs.
  • Pythonic
    Designed with Pythonic principles in mind, Assertpy fits seamlessly into Python projects, enabling idiomatic and consistent code style.

Possible disadvantages of assertpy

  • Learning Curve
    Developers new to the library may encounter a learning curve due to the distinct approach of using fluent and chainable assertions as opposed to traditional methods.
  • Limited by Python Version
    The library may have limitations in terms of compatibility with older versions of Python, requiring users to ensure their environment is up-to-date.
  • Performance Overhead
    The additional abstraction layer introduced by a fluent interface might introduce some performance overhead, especially in performance-critical or resource-constrained environments.
  • Less Community Support
    Compared to more established testing libraries, Assertpy might have less community support and fewer resources available for resolving issues or getting help.
  • Dependency Management
    Using a third-party library introduces additional dependencies to manage, which could complicate project maintenance and compatibility.

OnlineGridMaker features and specs

  • Grid Overlay
    Add customizable grid on any image with adjustable rows and columns
  • Perspective Guide
    1-point and 2-point perspective grid for drawing practice
  • Customizable Lines
    Adjust line color, thickness, and opacity to your preference
  • Cell Labels
    Optional A1, B2 style labels for precise reference
  • No Signup Required
    Open and use immediately, no account needed
  • 100% Local Processing
    All processing happens in your browser, no uploads to any server
  • Download Options
    Export as PNG or print directly
  • 100% Free
    Completely Free โ€” no signup, no premium version, unlimited use

Analysis of assertpy

Overall verdict

  • assertpy is a well-regarded, lightweight assertion library for Python that provides a fluent, chainable API for writing readable and expressive test assertions, making it a solid choice for improving test clarity.

Why this product is good

  • Offers a fluent, chainable assertion syntax that makes tests more readable and self-documenting
  • Comprehensive built-in assertions for strings, numbers, lists, dicts, files, dates, and more
  • Produces clear, descriptive failure messages that speed up debugging
  • Lightweight with minimal dependencies and easy to integrate into existing test suites
  • Framework-agnostic, working seamlessly with pytest, unittest, and other test runners
  • Actively maintained open-source project with good documentation and community support

Recommended for

  • Python developers who want more readable and expressive test assertions
  • Teams using pytest or unittest looking to enhance assertion clarity
  • Projects that value descriptive failure messages for faster debugging
  • Developers coming from fluent assertion libraries in other languages (like AssertJ or Chai)
  • QA engineers and testers writing maintainable, self-documenting test code

Analysis of OnlineGridMaker

Overall verdict

  • OnlineGridMaker is a solid, no-frills tool for quickly creating grid layouts, graph paper, and grid-based designs directly in the browser without needing to install design software.

Why this product is good

  • Free and easy to access online without registration
  • Simple interface that lets users generate custom grids quickly
  • Useful for printable graph paper, layout planning, and design mockups
  • No steep learning curve compared to full design software
  • Lightweight and fast-loading tool

Recommended for

  • Students needing graph paper for math or art projects
  • Designers sketching quick layout grids
  • Teachers preparing printable grid worksheets
  • Hobbyists working on cross-stitch, pixel art, or similar grid-based crafts
  • Anyone needing a fast, free grid-generation tool without installing software

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Add video

OnlineGridMaker videos

OnlineGridMaker โ€” Free Grid Overlay Tool for Artists

Category Popularity

0-100% (relative to assertpy and OnlineGridMaker)
Testing
100 100%
0% 0
Image Editing
0 0%
100% 100
Python
100 100%
0% 0
Design Tools
0 0%
100% 100

Questions & Answers

As answered by people managing assertpy and OnlineGridMaker.

What makes your product unique?

OnlineGridMaker's answer:

-Unlike most grid tools that only offer basic square grids, OnlineGridMaker combines customizable grid overlays (adjustable rows, columns, color, opacity) with perspective guides for 1-point and 2-point drawing. It also offers optional cell labels (A1, B2 style). Everything runs 100% locally in the browser โ€” no image uploads, no signup, no data ever leaves your device.

Why should a person choose your product over its competitors?

OnlineGridMaker's answer:

-Most alternatives either require installing software, force you to create an account, or upload your images to a server. OnlineGridMaker is completely browser-based, free forever with no premium tier, and processes everything on your device. Just open the page, upload a reference image, and start gridding in seconds. It's faster, more private, and zero friction compared to desktop apps or account-gated web tools.

How would you describe the primary audience of your product?

OnlineGridMaker's answer:

-Artists, illustrators, art students, and hobbyists who practice drawing from reference photos โ€” especially those learning proportion, composition, and perspective. Also useful for architects, designers, and educators who need quick grid overlays for teaching or planning purposes.

What's the story behind your product?

OnlineGridMaker's answer:

-Built by an independent developer who noticed that most free grid tools were either too basic (fixed grids only) or required downloading software. The goal was simple: a professional-grade, free grid overlay tool that respects user privacy by processing everything locally in the browser. No tracking, no uploads, no strings attached.

Which are the primary technologies used for building your product?

OnlineGridMaker's answer:

-Pure HTML, CSS, and JavaScript โ€” no frameworks, no backend, no dependencies. Hosted as a static site on Cloudflare Pages for global CDN delivery. The tool uses the HTML5 Canvas API for rendering grids and generating downloadable PNG images client-side.

Who are some of the biggest customers of your product?

OnlineGridMaker's answer:

ยทArt students using it for figure drawing and still life proportion practice

ยทFreelance illustrators who need quick grid references before starting digital paintings

ยทArt teachers incorporating it into classroom demonstrations

ยทComic artists using perspective guides for background layouts

User comments

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What are some alternatives?

When comparing assertpy and OnlineGridMaker, you can also consider the following products

grappa - grappa is an declarative, verbose, and expressive assertion library for Python.

GridMaker.org - Split any image into Instagram posts. Create stunning grid effects for your feed. Fast, free, and easy to use online tool.