# I open-sourced 3 small Node utilities I pulled out of building an edtech platform

> Source: <https://dev.to/ram_chandragiri/i-open-sourced-3-small-node-utilities-i-pulled-out-of-building-an-edtech-platform-28jd>
> Published: 2026-09-19 20:08:57+00:00

I've spent the last while building [MCQplex](https://mcqplex.com), an exam-prep

platform for Nepal's NEB curriculum. Along the way I built a few pieces of

infrastructure that had nothing to do with exams specifically, so I pulled

them out into their own packages:

Free-tier LLM APIs (Gemini, Groq, Cerebras, and others) are individually

rate-limited, but between them they add up to a lot of free inference if you

just fail over from one to the next. This cascades a chat completion across

however many you've got keys for, with automatic multi-key rotation (if

you've made more than one free account on a provider) and cooldown for a

provider that's structurally broken. Zero dependencies.

``` js
const { LLMCascade } = require('llm-free-cascade');
const cascade = LLMCascade.fromEnv();
const { text, provider } = await cascade.generate({ system, user });
```

Launching a fresh headless Chromium per PDF (the naive way to use Puppeteer)

costs 1-2 seconds and ~200MB of RAM every time. This keeps one browser warm

and gives each render its own page, with a concurrency cap so a burst of PDF

requests queues instead of taking the server down.

If you run `node-cron` jobs on more than one instance (PM2 cluster, several

servers), every instance fires the job unless you do something about it.

This is a tiny MongoDB-backed advisory lock — steal-on-expiry, so a crashed

holder can't deadlock the job forever — for whatever Mongo connection you

already have.

All three: zero or optional-peer dependencies, MIT licensed, tested, on npm.

Feedback / PRs welcome, especially on `llm-free-cascade` since free-tier

model names drift constantly and `providers.json` is set up so a one-file PR

fixes a stale one.