I built ZeroAPI — free AI tools for developers, no API key, no signup, ever

Abhishek Singh — Sun, 07 Jun 2026 09:55:22 +0000

I'm a CS professor from India. Between teaching, research, and writing books on KDP, I built ZeroAPI — https://zeroapi.in - a free AI tools platform for developers and students.

The whole thing started because I kept watching my B.Tech students struggle to access AI tools. ChatGPT API costs money. Most tools want a signup. Students in Tier 2/3 cities in India don't always have a credit card. So I built something with a hard rule: zero API key, zero signup, zero data storage. Ever.
What ZeroAPI does

Six tools, all free, all instant:

🎤 Mock Interview Simulator — Pick a role (SDE, Data Analyst, ML Engineer), difficulty, and get AI-generated questions with feedback on your answers. Good for cracking campus placements.

📋 Resume Analyzer — Paste your resume, get ATS score, strengths, weaknesses, and a section-by-section rewrite suggestion.

📄 Resume Builder — Guided wizard that outputs a clean, ATS-optimized resume. No templates to pay for.

⚡ Code Explainer — Paste any code snippet (Python, C++, SQL, JS) and get a plain-English breakdown. Great for reading unfamiliar codebases.

🔬 Research Summarizer — Paste an abstract or full paper. Get structured summary: problem, methodology, findings, limitations, gaps.

❓ MCQ Generator — Enter any topic, difficulty, and count. Generates exam-ready multiple choice questions instantly. Used by teachers and GATE/placement aspirants.

The Learn section

Beyond tools, ZeroAPI has a Learn section — technical articles written for developers and job seekers. Things like:

How Agentic AI Actually Works (with Python)
50 Python Interview Questions for 2026
System Design Interview Patterns
CUDA GPU Programming Deep Dive

and many such articles. Each article links directly to the relevant tool so you can practice immediately after reading.

The Roadmaps section
ZeroAPI also has structured learning roadmaps — interactive knowledge graphs with phase-by-phase learning paths, skill assessments to skip what you already know, topic checkboxes to track progress, and curated resources per phase.
Roadmaps for: Full Stack, Data Science, ML, DevOps, Cybersecurity, and more.

The BreakIt section

My favourite part: BreakIt — a debug challenge arena where you fix deliberately broken code.
Real bugs. Real explanations. No toy puzzles.
Examples:

The Silent Data Killer — dropna() silently removes valid rows. Your revenue is wrong but looks right.
The Accuracy Trap — You reported training accuracy. Your ML model is useless in production.
The Empty Set Trap — NOT IN with a subquery containing NULLs returns zero rows silently.
Floating-Point FinTech Flaw — Binary floats can't represent 0.1 accurately. Your audit fails.
Mutable Default Disaster — Using [] as a default argument creates shared state across calls.

Each challenge has: broken code → hint system (reveal one at a time) → solution → explanation → lesson. Categories cover Python, ML, SQL, JavaScript, Systems/C++.

The stack

React + Vite frontend, deployed on Vercel
Groq (llama-3.3-70b-versatile) as AI backend — chosen for speed
Serverless Vercel API routes as proxy (API key never exposed to client)
Upstash Redis for article view telemetry and blog reactions
Pure JS arrays for the blog/challenge data (no CMS, no database for content)
No ads. No tracking. No dark patterns.

What I'm looking for

Honest feedback on:

Which tool do you find most useful?
What's missing that you'd actually use?
Any bugs you find in the BreakIt challenges (meta, I know)
The platform is actively being developed. Roadmaps and BreakIt are the newest additions.

→ zeroapi.in
Built by Prof. Abhishek Singh — CS professor, KDP author, and builder of things. Also runs @pyofpython on YouTube.
If this is useful to even one developer who couldn't afford API credits, it's worth it.

DEV Community: Abhishek Singh

I built ZeroAPI — free AI tools for developers, no API key, no signup, ever