Bun vs Node.js: Performance and Stability in 2026

Engine competition and runtime speed

Node.js 24 provides significant updates through its V8 13.6 engine. This upgrade introduces Float16Array for memory-efficient storage and a stable URLPattern API for matching URLs. It also includes native Iterator Helpers that allow developers to perform operations like .map() and .filter() more efficiently. Bun 1.4.2 remains the stable choice for developers wanting integrated tools, while Node.js 24 provides the LTS stability for enterprise production. Bun 1.4.0 replaced the previous Zig-based architecture with a Rust rewrite in August 2026. Bun’s 1.4.0 release in August 2026 replaced the previous Zig-based architecture with a Rust rewrite to improve stability, although the tool still targets Node.js 23 as its primary compatibility baseline for module resolution and API parity. Bun’s homepage claims 48,243 requests per second for HTTP throughput. However, a 2025 peer-reviewed study by JCSI measured 27,500 requests per second for Bun and 28,200 requests per second for Node.js. Bun’s package manager provides a speed advantage that persists even after the runtime’s shift to Rust. For a fixture containing 220 packages, Bun completes a first install in 1.41 seconds. In comparison, npm takes 18.12 seconds and Yarn requires 20.51 seconds for the same task. This speed advantage remains useful for developers working in CI/CD pipelines where build times impact cost. I find the integrated nature of the Bun CLI, including bun test and bun build, simplifies the toolchain significantly.

Security, memory, and production reliability

Node.js 24 uses OpenSSL 3.5, which raises the default security level to 2 and rejects RSA/DSA keys under 2048 bits. This change makes Node.js a better choice for regulated industries. Node.js also includes the stable --permission flag, which was renamed from --experimental-permission in version 24.0.0. Bun lacks a runtime permission system. Its attempt to add "Secure Mode" via pull request #25911 failed when the proposal closed in June 2026. You should use OS-level sandboxing if you deploy Bun for untrusted workloads. Dependency risks exist in both runtimes, as evidenced by the 2025 supply-chain attacks where malicious packages like chalk@5.6.1 redirected cryptocurrency transactions. The 2026 axios@1.14.1 remote-access trojan shows that package security remains a variable. Bun’s 1.4.2 release passes 97% of the node:http, node:fs, and node:stream test suites, yet it still lacks official support from frameworks like Fastify, NestJS, Datadog, or OpenTelemetry. Memory usage also differentiates the two. In a Next.js standalone server test, Bun 1.4.0 used 318 MB of memory after 45 seconds of idle time, whereas Node 24 used only 80 MB. I find the memory consumption of Bun in framework-heavy workloads to be a significant drawback.

Deployment and ecosystem suitability

Deployment patterns vary by provider. AWS Lambda offers managed runtimes for Node.js 26.x, 24.x, and 22.x, but developers must use custom layers or Docker containers to run Bun. This non-standard approach for Bun increases cold-start latency because the runtime must download repeatedly. Strapi 5 remains incompatible with Bun as a server runtime, as it requires Node.js 22, 24, or 26 to function. Developers can use Bun for frontend tasks while keeping the backend on Node.js for Strapi projects. Anthropic’s acquisition of Bun on December 3, 2025, integrated the runtime into their AI-driven development stack. This move helped power Claude Code, which reached a $1 billion run-rate shortly after launch. Bun’s Windows support is now mature, with Windows ARM64 arriving in version 1.3.10. I find the versioning in Bun to be unreliable, as patch releases often introduce new features. Will Bun’s Rust rewrite eventually bridge the memory gap that remains between it and Node.js?