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Life & fun · alternatives · 2026

24 alternatives to Spall – WASM-based profiler for JavaScript and C and Odin

[I'm the author] Spall is a web-accessible profiler that I made to help my web-dev friends load gigabyte+ JSON traces without lunch-break-long load times. Recently, Spall got experimental support for auto-tracing with binary traces (along with an in-progress native-port, to give it more memory headroom), which was used to help track down and fix some hard-to-spot lock contention issues in the Odin-language compiler. I demoed it at the Handmade Seattle conference in October, https://guide.handmade-seattle.com/c/2022/spall/, with a head-to-head against Perfetto,…

Spall is a web-based profiler designed to quickly load and analyze large JSON trace files for performance analysis. It supports JavaScript, C, and Odin, and features experimental binary trace auto-tracing capabilities.… Below are 24 products that do a similar job, ranked by how close each is in meaning and then by launch-day votes. Spall – WASM-based profiler for JavaScript and C and Odin launched in 2023; newer entries below may have overtaken it.

  1. 1

    I've open sourced a JavaScript to WASM compiler. It's an experimental tool, but given the semantics I already implemented, I'm fairly certain I am able to eventually cover 100% of JavaScript spec. Any ideas, questions or critique welcomed! If you are interested in WASM, especially with new proposals like WASM GC or exception handling, it might be a good source of seeing these features in action - the project has a few thousand lines of hand written WAT so far.

    2024 · github.com · its alternatives →

  2. 2

    If you've built any web-based app in the last 15 years, you probably used something like Datadog, New Relic, Sentry, etc. to monitor and trace your app, right? Why should it be different when the app you're building happens to be using LLMs? So today we're open-sourcing OpenLLMetry-JS. It's an open protocol and SDK, based on OpenTelemetry, that provides traces and metrics for LLM JS/TS applications and can be connected to any of the 15+ tools that already support OpenTelemetry. Here's the repo: https://github.com/traceloop/openllmetry-js A few months ago we launched…

    2024 · github.com · its alternatives →

  3. 3

    Ditch your scraper. Make one API call with any tool.

    Jun 2026 · tabstack.ai · its alternatives →

  4. 4

    Here's a project I've been working on for a little while now. Ripl is a JS library that provides a unified API for rendering shapes on both canvas and SVG interchangeably. Over the years I've used D3 extensively to create data visualisations so I figured I'd have a go at making my own version with a slightly more modern API and stricter TypeScript support. I am aware there are already libraries that can draw to multiple contexts interchangeably, but I've added a few little niceties to Ripl that (as far as I know) some other libraries don't have such as CSS-like query selectors, DOM-like…

    2024 · github.com · its alternatives →

  5. 5

    allocscope - a memory tracking tool. Contribute to matt-kimball/allocscope development by creating an account on GitHub.

    2023 · github.com · its alternatives →

  6. 6

    Find the origin of any character in the DOM

    2019 · fromjs.com · its alternatives →

  7. 7

    Hey HN. We’re Jay and Vadim from Highlight.io (https://highlight.io). We’re building an open source [1] monitoring platform for web applications. Today we’re excited to be sharing a performance tool we’ve been working on, which helps you inspect the latency of code execution from the client to the server. As engineers at past startups, we often had to debug slow queries, poor load times, inconsistent errors, etc... While tools like Jaegar [2] helped us inspect server-side performance, we had no way to tie user events to the traces we were inspecting. In other words, although we had…

    2024 · github.com · its alternatives →

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    Hey HN! We’ve built Pretzel, an open-source data exploration and visualization tool that runs fully in the browser and can handle large files (200 MB CSV on my 8gb MacBook air is snappy). It’s also reactive - so if, for example, you change a filter, all the data transform blocks after it re-evaluate automatically. You can try it here: https://pretzelai.github.io/ (static hosted webpage) or see a demo video here: https://www.youtube.com/watch?v=73wNEun_L7w You can play with the demo CSV that’s pre-loaded (GitHub data of text-editor adjacent projects) or upload…

    2024 · github.com · its alternatives →

  10. 10

    Two months ago, I started building this side-project in the morning, before my full-time job. A visual and easy-to-use web scraping app. Please, roast it a bit so I can work on improving it. Thanks.

    2023 · mrscraper.com · its alternatives →

  11. 11SA

    I've frequently found myself using [nvitop](https://github.com/XuehaiPan/nvitop) to diagnose GPU/CPU contention issues. The two best things about it are: - It's easy to install if I can access pip in the container - It makes a compelling screenshot (which helps me communicate with coworkers.) With those two lessons in mind: Here is Sping! Purpose: Help observe and diagnose latency issues at layer 4+ (TCP/HTTP/HTTPS) Two good things about it: - It's easy to install if you have pip. (Available at…

    2025 · dseltzer.gitlab.io · its alternatives →

  12. 12OA

    A lightweight engine for durable execution / deterministic workflows I built with Rust, wasmtime and the WASM Component Model. Its main use is running reliable, long-running workflows that can automatically resume after failures. Looking for feedback on the approach and potential use cases!

    2025 · obeli.sk · its alternatives →

  13. 13

    Hi Hacker News! We’re Vadim and Chris from Highlight.io [1]. We do web app monitoring and are working on using LLMs/embeddings to add new functionality to our error monitoring product. Given that there’s a lot of founders/engineers using LLMs in their products, we figured we’d share how we built the new functionality, their impact on our workflows, and how you can try it out. Our goal was to build two features: (1) tagging errors (e.g. deeming an error as “authentication error” or a “database error”); and (2) grouping similar errors together (e.g. two errors that have a different…

    2023 · github.com · its alternatives →

  14. 14

    DEPRECATED StackImpact Python Profiler - Production-Grade Performance Profiler: CPU, memory allocations, blocking calls, exceptions, metrics, and more - stackimpact/stackimpact-python

    2017 · github.com · its alternatives →

  15. 15
  16. 16

    Hi HN! I'm building a JavaScript debugger called Wirebrowser. It combines network inspection, request rewriting, heap snapshots, and live object search. The main experimental feature is BDHS (Breakpoint-Driven Heap Search): it hooks into the JavaScript debugger and automatically captures a heap snapshot at every pause and performs a targeted search for the value or structure of interest. This reveals the moment a value appears in memory and the user-land function responsible for creating it. Another interesting feature is the Live Object Search: it inspects runtime objects (not just…

    Dec 2025 · github.com · its alternatives →

  17. 17

    I found hping3 and nmap's nping to be far too slow in terms of sending individual, bare-minimum (40-byte) TCP SYN packets; other than inefficient socket I/O, they were also attempting to do far too much unnecessary processing in what should have otherwise been a tight execution loop. Furthermore, none of them were able to handle CIDR notations (i.e., a range of IP addresses) as their source IP parameter. Being intended for embedded devices (e.g., low-power MIPS/Arm-based routers), Blitzping only depends on standard POSIX headers and C11's libc (whether musl or gnu). To that end,…

    2024 · github.com · its alternatives →

  18. 18LB

    Hey HN, Spark event logs run into 100s of MBs and offer a wealth of insight into your workloads but making sense of them has always been quite a bit prohibitive. We’ve recently built a lightweight tool that automatically parses Spark event logs and surfaces targeted insights to help you optimize your data jobs. Whether you’re chasing down a bottleneck or balancing performance vs. cost, the profiler got you covered with real-time configuration recommendations, data skew analysis, and more. Curious how it works in action? Check out this quick Loom video for a walk-through:…

    2025 · datasre.ai · its alternatives →

  19. 19

    We've been building data pipelines that scrape websites and extract structured data for a while now. If you've done this, you know the drill: you write CSS selectors, the site changes its layout, everything breaks at 2am, and you spend your morning rewriting parsers. LLMs seemed like the obvious fix — just throw the HTML at GPT and ask for JSON. Except in practice, it's more painful than that: - Raw HTML is full of nav bars, footers, and tracking junk that eats your token budget. A typical product page is 80% noise. - LLMs return malformed JSON more often than you'd expect, especially with…

    Mar 2026 · github.com · its alternatives →

  20. 20RA
  21. 21

    Easy to use GraphQL performance analysis utility for tracing resolver execution time - Econify/graphql-request-profiler

    2022 · github.com · its alternatives →

  22. 22

    This is a small PoC Python project for web server access logs analyzing to classify and dynamically block bad bots, such as L7 (application-level) DDoS bots, web scrappers and so on. We'll be happy to gather initial feedback on usability and features, especialy from people having good or bad experience wit bots. *Requirements* The analyzer relies on 3 Tempesta FW specific features which you still can get with other HTTP servers or accelerators: 1. JA5 client fingerprinting (https://tempesta-tech.com/knowledge-base/Traffic-Filtering-b...). This is a HTTP and TLS layers…

    2025 · github.com · its alternatives →

  23. 23

    Blunders is a web-based profiler of JVM applications. Understand and fix performance problems, faster.

    2020 · blunders.io · its alternatives →

  24. 24

    Note: this is an update to [this](https://news.ycombinator.com/item?id=44568529) "Show HN" post. timep is a state-of-the-art [debug-]trap-based bash profiler that is efficient and extremely accurate. Unlike other profilers, timep records: 1. per-command wall-clock time 2. per-command CPU time, and 3. the hierarchy of parent function calls /subshells for each command the wall-clock + CPU time combination allows you to determine if a particular command is CPU-bound or IO-bound, and the hierarchical logging gives you a map of how the code actually executed. The standout…

    2025 · github.com · its alternatives →

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