AMARTUVSHIN

My part: UI/UX lead and testingBased on our final capstone report, spring 2026

1. 01 / 06 · Report

   A bug report comes in

   A developer types a short description of what went wrong, and Spotfixes sends it to the server to be checked.

   Example report

   Browser tab crashes when uploading a large file
2. 02 / 06 · Security

   It checks who's asking

   Every request carries a signed login token, and the server turns away fake or expired ones. Each company can only ever see its own bugs.

   Put simplyThink of an apartment building: every company has its own front door, and nobody can walk into someone else's flat.

   • Fake loginsA stolen or forged login token→ Its signature and expiry are checked, over HTTPS only
   • Data leaksOne company seeing another's bugs→ Every row of data is locked to its own company
   • Too much accessA regular user trying admin actions→ The server checks each user's role first
3. 03 / 06 · Severity

   It rates how serious the bug is

   A machine-learning model scores each word, then hundreds of small decision trees vote on a rating from S1 (most serious) to S4. Words like “crash”, “security” or “leak” always make it S1.

   Put simplyThe model can't read English, so each word gets a score for how much it matters: “crash” scores high, “the” scores zero.

   Word scoresExample

   • browser
   • tab
   • crashes
   • uploading
   • large
   • file

   Tree votesExample

   S2S1S2S3S2S2S1S2S3S2S1S2

   Most votesS2

   Browser tab crashes when uploading a large file

   S2→S1Rule · Keyword: “crash”
4. 04 / 06 · Duplicates

   It finds similar past bugs

   It also searches earlier reports by meaning, not exact wording, so the developer sees likely duplicates before saving a new one.

   Put simply“Freezes” and “hangs” still count as a match.

   Meaning, as numbersExample

   Example from our final presentation

   New bug

   “Browser freezes when opening a PDF with more than 100 pages”

   Matches found before it was saved

   • “App hangs on large PDF documents — memory spike observed”

     92% similar

   • “PDF viewer unresponsive after loading document over 80 pages”

     78% similar
5. 05 / 06 · Results

   Fast and accurate

   Our goal was an answer in under 5 seconds. On average the rating took 3.4 seconds and the duplicate search 1.2. The model learned from 222,000 real Firefox bug reports, with 20% kept aside for testing.

   Put simplyIn the grid, each row is what a bug really was and each column is what the model guessed. The diagonal is every right answer.

   Severity rating3.4 s

   Duplicate search1.2 s

   Goal < 5 s

   accuracy, final report89%

   Accuracy

   97.6%

   Final presentation: every record scored, training data included

   S1S2S3S4ActualS114,3749911930S223617,32719851S31,7481,140144,2171,476S4883233444,189

   Confusion matrix, S1 to S4

   Actual / Predicted	S1	S2	S3	S4
   S1	14,374	99	119	30
   S2	236	17,327	198	51
   S3	1,748	1,140	144,217	1,476
   S4	88	32	334	44,189

   That's why it reads higher than the report's 89%: a model always does better on bugs it has already seen. When an engineer corrects a rating, the correction goes back into training.

6. 06 / 06 · My part

   My part: design and testing

   I set the design rules every screen follows, so the app feels like one product whoever built each page. Then I ran a usability test with real users and logged every problem by priority until it was fixed.

   GoalResult: Partly met

   A new company admin goes from sign-up to retraining the model in under 8 steps, without being logged out

   of tasks finished without a problem

   60%

   average difficulty

   3.8 / 5

   What got in the way: testers were logged out twice mid-task, and sign-up created a duplicate admin.

   • HighSign-up created a duplicate admin→ Added a check that stops duplicatesFixed
   • HighRetraining stuck at 0%→ The progress bar now shows real progressFixed
   • MediumLanding-page buttons did nothing→ Every button now goes where it saysFixed
   • LowA confusing light/dark switch→ Moved to a normal menu in SettingsFixed
   • CriticalLogged out on the Settings page→ Traced to the serverStill open when the report was written