Compare 99tests vs. Stably

99tests is a crowdsourced testing service that operates on a fixed-price model, designed specifically for evaluating mobile applications and websites. Teams can upload their builds or URLs, submit test cases that can include AI-generated scenarios, and select from a variety of device and browser options. Testers located in India execute these cases using their personal devices, such as smartphones, laptops, and browsers. Upon completion, 99tests provides a comprehensive report that is verified by humans, detailing pass/fail results, steps to reproduce issues, and a comparison of expected versus actual behavior, along with specifics about the device and operating system used, and visual evidence like screenshots or recordings. Additionally, the platform features a hosted workflow that includes an MCP server, enabling coding clients to access package information, create jobs, monitor their status, and download reports, with payments facilitated through a browser checkout system. Companies utilize 99tests for both release validation and regression testing, allowing them to leverage real devices without the overhead of maintaining an internal device lab or dedicated QA personnel. Each fixed-price package outlines the number of sessions, the selected devices or browsers, limits on test cases, and expected turnaround times, making the service transparent and predictable. Furthermore, 99tests provides free online QA tools, enhancing the resources available for quality assurance efforts. This combination of features makes 99tests a valuable asset for teams striving for quality in their software development process.

Stably is a browser and end-to-end testing solution that utilizes AI to assist software teams in their development processes. Customers can describe their workflows in straightforward terms or capture them, leading to the generation of reviewable Playwright tests that can be executed on Stably Cloud or integrated into their existing CI setups. The platform offers comprehensive features such as test planning, browser execution, screenshots, video recordings, and detailed trace data, all aimed at aiding teams in analyzing outcomes and diagnosing issues. It has the capability to detect discrepancies in tests and suggest necessary adjustments as web interfaces evolve, ensuring that updates undergo review through Git pull requests instead of being applied automatically. Stably is designed to assist QA specialists, product managers, and developers who are tasked with the creation, execution, and maintenance of browser-based validation checks for web applications, which include vital processes like release regression, checkout flows, authentication, forms, and various multi-step user interactions. Furthermore, teams are able to link their testing coverage directly to repositories, Jira tasks, and product documentation, while seamlessly incorporating Playwright code into their established development workflows. This integration allows for a more cohesive and efficient approach to managing quality assurance and development tasks.