Phanindra Vallabhajosyula

šŸ„‡ Ranked #1 in Speed Coding Challenge

May 1, 2025

A geeky developer wearing a gold #1 medal, sitting atop a pyramid with a MacBook, surrounded by a futuristic city.

In 2021, I took part in the Toptal JavaScript Speed Coding Challenge. The goal? Solve 30 coding challenges in under three minutes. That's right - 180 seconds to:

  • Read the problem
  • Understand what's being asked
  • Think of a working algorithm
  • Code it
  • Submit the solution

Sounds wild, right? It was.

But what followed was a story of experimentation, automation, reverse engineering, and ultimately, a little help from the cloud.


šŸŽÆ The Rules

  • Complete 30 coding puzzles as fast as possible.
  • You can make unlimited attempts.
  • You get bonus points: +10 for every second left when you submit.

šŸ” First Attempt: Manual Prep

My strategy was simple:

  1. Attempt 1: Read and store all the challenges.
  2. Solve them calmly offline and keep the answers in a Word doc.
  3. Attempt 2: Copy-paste each solution as fast as possible.

It worked. I submitted within 180 seconds.

Result: Decent score, but far from the top.
Mistake: I thought speed = copy-paste accuracy. šŸ˜…


āš™ļø Second Attempt: Scripted Copy-Paste

Time to automate the grunt work.

  • I wrote a script to auto-fill the answers in the browser.
  • Submissions were done in under 20 seconds.

Result: Better score, still not #1.
Observation: There's a ceiling even with automation.


🧠 Third Attempt: Reverse Engineering the System

Here's where things got interesting.

While inspecting the app, I noticed:

🧩 The browser wasn't sending my code to the server - only the results.

That changed everything.

I built a new approach:

  • Use the user token to fetch challenge data.
  • Pre-map every challenge to its solution.
  • Run each challenge locally using its dynamic parameters.
  • Submit just the final output via POST.

Result: Submissions in under 7 seconds.
Standing: Top 10 in India.
But I wasn't done yet.


šŸ“” Final Breakthrough: Cutting Latency with AWS

One bottleneck remained: Network Latency.

  • The Toptal server was located in the US East zone.
  • I was running this from India, which meant 2-3 seconds lost in transit.

šŸ’” Solution: I spun up an EC2 instance in AWS's US East (N. Virginia) region.

  • Transferred my script.
  • Ran it remotely.
  • Results zipped across the network in milliseconds.

Final Result: Submission in under 4 seconds.
šŸ† Ranked #1 in the Indian Region.


šŸ“Œ Takeaways

  • Tools matter, but so does understanding the system you're working with.
  • Automation isn't cheating - it's engineering.
  • Latency is real - and sometimes, geography is the final boss.

šŸ“ˆ Leaderboard

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Thanks for reading.
Namaskaram šŸ™