The Grafana k6 team releases a new version of its open-source load testing tool approximately every two months, bringing new features and improving user experience. Several recent updates have introduced key improvements, notably related to TypeScript support, ECMAScript compatibility, and enhancements to browser testing, gRPC, memory management, cryptography, and test result storage.
One of the major updates introduced in the k6 version 0.52 release is allowing native support for TypeScript. Previously, developers using TypeScript with k6 were required to bundle their scripts using tools like Webpack or Rollup before running them. With this update, TypeScript tests can now be run directly from the k6 command-line interface (CLI) by using a special compatibility mode option. This new feature significantly simplifies the testing process for developers who prefer TypeScript, making it easier to work with k6, especially when reusing existing TypeScript libraries.
In addition to TypeScript, the v0.52 release also introduced support for a range of ECMAScript 6 (ES6) and newer features that had previously been unavailable in k6. These include features like optional chaining, object spread, and private class fields. By incorporating these ECMAScript (ES+) features, k6 has become more compliant with the modern JavaScript ecosystem, allowing developers to utilize contemporary JavaScript syntax without the need for workarounds. As of the k6 v0.53 release, these ES6+ features are now available in the default compatibility mode, making it even easier for developers to use them without any special configuration.
Another area of focus in recent k6 updates has been the browser testing module. Initially introduced in 2021, the browser module did not support asynchronous operations or the JavaScript async and await keywords. This changed with the k6 v0.52 release, where browser APIs were made fully asynchronous, aligning with the broader JavaScript ecosystem and ensuring compatibility with tools like Playwright. This update has made the browser testing experience more user-friendly and intuitive, although it did introduce breaking changes to existing browser scripts. To help users adapt to these changes, the k6 team provided a migration guide detailing the affected APIs and how to modify existing scripts to ensure compatibility. The browser module has now officially graduated from experimental status to a core module, making it stable and available under k6/browser instead of k6/experimental/browser.
Alongside the browser module, the gRPC streaming functionality also underwent significant changes. In the k6 v0.51 release, the grpc. Stream feature, which supports bi-directional gRPC streaming, was fully integrated into the stable k6/net/grpc module. This graduation ensures that no further breaking changes will occur, allowing developers to confidently use the gRPC APIs in their tests and upgrade to future versions without concern. In addition, the gRPC module now supports non-blocking asynchronous operations with the client.asyncInvoke method, which returns a Promise and provides more efficient performance.
The k6 v0.51 release also addressed the challenge of running load tests with large files, which previously led to Out of Memory (OOM) errors. While the SharedArray object had provided some relief, it still loaded all file content into memory. To tackle this, the k6 team introduced the Stream module, which allows developers to read large files in small chunks, reducing memory consumption and significantly improving efficiency. The new Stream API enables k6 to handle large datasets by loading them piece by piece, preventing OOM issues during testing.
Additionally, the k6 v0.51 release made common JavaScript timer methods like setTimeout, clearTimeout, setInterval, and clearInterval globally available. Previously, these methods had to be imported from the k6/timers or k6/experimental/timers modules. By making these methods globally accessible, k6 now aligns more closely with the behaviour of other JavaScript environments and simplifies the process of managing asynchronous operations within tests.
Cryptographic operations have also seen improvements in recent k6 releases. The tool now supports additional Web Crypto methods, including new asymmetric cryptography algorithms such as ECDH and ECDSA, along with support for pkcs8 and spki formats. It also supports the import and export of keys in JSON Web Key (JWK) format, further enhancing k6’s ability to test secure applications that use cryptography. While the webcrypto module remains a work in progress, these updates are a step forward in making cryptographic testing more robust within k6.
Finally, the integration of OpenTelemetry (OTEL) into k6’s core functionality was another important update introduced in the k6 v0.53 release. OTEL has become a standard for telemetry and observability, and its inclusion in k6 allows users to send test results directly to OpenTelemetry backends. This addition enables k6 users to map k6 metrics and tags to OTEL equivalents and output test results to default OTEL exporters without needing additional configurations. This further expands k6’s flexibility in how test results are stored and analyzed, integrating it with industry-standard telemetry tools.
In addition to k6, other noteworthy load testing tools include Autocannon and Locust. Autocannon, written in Node.js, is a fast HTTP benchmarking tool designed for testing web server performance under heavy traffic. It provides key metrics like throughput and latency. Meanwhile, Locust is an open-source load testing tool that uses Python scripts to define custom user behaviour. It can simulate millions of concurrent users, making it ideal for large-scale performance testing.