Caliber.

1. 01 · The problem

   Colleges need proof that students can code.

   Before placement season, engineering colleges need to know which students can really code. BLC trains those students, and I built the platform they practise and test on.

2. 02 · Why I built it

   Someone had to build all of it.

   The editor, the judge that runs the code, timed exams, contests, learning paths, payments and the security around them. I took it on and built nearly all of it myself, working day and night.

3. 03 · The hard part

   Exam day.

   Whole batches of students sit the same timed test at once, with proctoringWatching over an online test to stop cheating. (Watching over an online test to stop cheating.) on. I built the platform to carry that load: it is sized for about 1,000 students at once and 18 code submissions a second.

4. 04 · Where it is now

   In use at colleges.

   BLC sells Caliber to colleges, and 5,000+ students use it across 27 colleges.

Who stays in controlBLC owns all of it: its own code, its own servers, and its own judge, with no per-seat rent to anyone.

Hover a marked term to decode itTap a marked term to decode it

• Code in the browser

  Students write code in an in-browser editor, and test results stream back live.

• Judged in a sandbox

  Each submission is queued and run on a self-hosted Judge0An open-source engine that compiles and runs code safely in a sandbox. (An open-source engine that compiles and runs code safely in a sandbox.), inside an isolated sandbox.

• Tests by batch

  Timed tests mix multiple-choice and coding questions, grade themselves, and are assigned by college, branch and year.

• Proctoring that records

  Webcam, fullscreen exits, devtools and duplicate sessions are recorded for review after the exam. It never ends a test on its own.

• Practice that adds up

  Problems, contests with live leaderboards, learning paths, a playground and XP.

• An assessment builder

  A wizard, Excel bulk import, a question bank, and per-student problem variants with their own test data.

• Placement drives

  Eligibility, reminders, offers and placement analytics, with a NAAC export for colleges.

• Verified portfolios

  Each student gets a portfolio with GitHub and skill verification.

• Payments

  Assessment packs paid through Razorpay, with coupons.

• Locked-down accounts

  httpOnly cookies, bcrypt, a 15-minute lockout after five failed logins, and rate-limited sign-in.

1. 01 · Placement season

   A whole batch at once.

   A college runs one timed coding test for every student in the batch.

2. 02 · Day to day

   Practice between tests.

   A training cohort works through learning paths and the playground.

3. 03 · A recruiter drive

   From eligibility to offers.

   The placement cell runs the drive end to end and exports the data for NAAC.