TopCoder.App User Guide

Overview

TopCoder.App is a macOS desktop application that provides real-time AI assistance during technical interviews. It runs as an invisible overlay on your screen, completely undetectable by screen sharing and screenshot tools.

The app listens to your interviewer in real time, can capture and analyze any coding problem on screen, and generates solutions with exactly what to say, all without your interviewer seeing anything.

Installation

Stealth Verification (Optional)

TopCoder uses proprietary stealth technology to be completely invisible to all screen capture tools at the operating system level. This means:

• Invisible to screen share on Zoom, Google Meet, Teams, Webex, and all other meeting platforms
• Hidden from screenshots taken by other applications
• Not visible in Dock, Mission Control, Exposé, or Cmd+Tab app switcher
• Undetectable by monitoring or proctoring software

For extra peace of mind, you can verify this yourself:

1. Open TopCoder.App so the overlay is visible on your screen.
2. Start a video call on Zoom, Google Meet, or any platform you use.
3. Share your entire screen.
4. Join the same call from your phone (or ask a friend to check).
5. Confirm the TopCoder overlay is completely invisible on the shared screen.

Your First Interview

1. Launch TopCoder.App before your interview starts. The overlay appears as two panels: a control strip at the top and an answer panel below it.
2. Start a session. TopCoder will ask if you want to enable Extreme Stealth — this hides the overlay from mouse detection by proctoring platforms like HackerRank and CodeSignal. We recommend enabling it for any proctored assessment.
3. Start listening. This captures your interviewer's voice through system audio and transcribes it in real time.
4. Join your video call as you normally would. Share your screen if asked. TopCoder is invisible.
5. When a question comes up, you have two options:
   • Screenshot and analyze the visible code or problem
   • Ask for AI help based on the conversation transcript
6. Read the AI response on your overlay. It includes what to say, solution code, complexity analysis, and follow-up suggestions. Scroll through it using the keyboard shortcuts shown on screen.
7. Minimize when not needed. The app shrinks to a small dot in the corner.

Screenshot Analysis

Screenshot analysis is TopCoder's most powerful feature. It captures your screen at double resolution and sends it to AI for vision-based analysis.

The AI response includes:

• Complete, runnable solution code in your preferred language
• Time and space complexity analysis
• A natural speaking script: what to say as you write the solution
• Clarifying questions to ask the interviewer (categorized as "need to ask" vs "nice to ask")
• Multiple solution approaches ranked by optimality

Live Transcription

TopCoder captures your interviewer's voice through system audio and transcribes it in real time using Deepgram's Nova-2 speech-to-text model. The transcript is displayed in an expandable panel and used as context when you ask for AI help, so the AI knows exactly what was discussed.

Auto-Detection

TopCoder continuously monitors the conversation and alerts you in three situations:

Alerts appear as a subtle pulsing indicator. Tap it or use the AI help shortcut to get instant assistance. There's a 10-second cooldown between alerts to avoid distraction.

Knowledge Base

The knowledge base lets you save your own preparation materials (notes, cheat sheets, STAR stories, company research) directly in the app. TopCoder indexes them in a built-in vector database so it can reference them during your interview and weave them into answers that sound like you.

Projects

Files are organized into projects. You might create one project per company or per interview type:

• Up to 3 projects per account

Supported File Types

File Limits

How It Works

When you save a file, TopCoder breaks it into sections, generates vector embeddings, and stores them for fast similarity search. All plans include a built-in local vector database that runs entirely on your Mac with no cloud setup required. During an interview, when you ask for help, TopCoder automatically searches your knowledge base for relevant content and includes it in the AI prompt, so the response incorporates your own notes, examples, and talking points.

Talk-Through Script

Every solution comes with a line-by-line explanation you can read right off the screen. Walk your interviewer through the logic like you wrote it yourself. The script covers:

• Why you chose this approach over alternatives
• Step-by-step walkthrough of the algorithm logic
• Time and space complexity justification
• Edge cases and how the code handles them

The script is written in natural conversational language — not code comments — so you can read it aloud naturally while walking through your solution. It's displayed alongside your code in the solutions view.

Solutions View

When TopCoder generates a solution for a coding problem, it presents multiple approaches in a tabbed view. Each approach has five tabs you can switch between using Ctrl+Shift+Left/Right:

Keyboard Shortcuts

All shortcuts are global and work even when TopCoder is not the active window or when the overlay is in Extreme Stealth passthrough mode. Every shortcut is also labeled on screen — press Ctrl+Shift+/ to view the full list inside the app.

Primary — most used during interviews

Secondary

Extreme Stealth Mode

Platforms like HackerRank, CodeSignal, CoderPad, and other proctored assessment tools monitor browser activity. They track when your mouse leaves the browser window by listening for mouseleave and blur events. If you move your mouse to interact with another window, these platforms can flag it as suspicious activity.

Extreme Stealth solves this completely. When enabled, TopCoder becomes invisible to mouse detection — all clicks pass straight through to the browser underneath, so platforms never see your mouse leave.

Extreme Stealth ON (Green Border)

When Extreme Stealth is active, you'll see a green border around the panels and an "Extreme Stealth Active" banner. The overlay is completely transparent to all mouse events — your mouse passes straight through to the browser, so it never triggers mouseleave or mouseenter events. It's safe to move your mouse anywhere on screen.

What works in Extreme Stealth:

• All keyboard shortcuts (Ctrl+Shift+A, Ctrl+Shift+J, Ctrl+Shift+Up/Down, etc.)
• Screenshot & analyze
• Scrolling the answer panel with Ctrl+Shift+Up / Ctrl+Shift+Down
• Typing via Ctrl+Shift+I to focus input, then Enter to send
• Dictation via Ctrl+Shift+D
• Clearing context with Ctrl+Shift+K
• Switching between approaches with Ctrl+Shift+[ / Ctrl+Shift+]

What does NOT work in Extreme Stealth:

• Clicking buttons on the overlay
• Scrolling with the mouse wheel
• Dragging or resizing panels
• Clicking inside the text input box

Extreme Stealth OFF (Red Border)

Press Ctrl+Shift+E to disable Extreme Stealth. The border turns red. In this mode, you can click buttons, drag panels, and use the mouse on the overlay — but your mouse is no longer invisible to the browser. Do not move your mouse over the overlay when the border is red if the coding platform is monitoring mouse events. Press Ctrl+Shift+E again to re-enable Extreme Stealth.

Typing Without the Mouse

You can type questions to TopCoder entirely from the keyboard while Extreme Stealth is active:

1. Press Ctrl+Shift+I to focus the "Ask anything" text input.
2. Type your question. Or press Ctrl+Shift+D to dictate it by voice.
3. Press Enter to send.
4. Press Ctrl+Shift+I again to blur the input when done.

Interview Types

Coding & Algorithm Interviews

TopCoder's primary strength. When you screenshot a coding problem from LeetCode, HackerRank, CoderPad, or any coding platform, it:

1. Identifies the problem type (arrays, trees, graphs, DP, etc.)
2. Generates multiple solution approaches ranked by optimality
3. Provides complete, runnable code in your preferred language
4. Includes time/space complexity analysis
5. Writes a speaking script for what to say as you code
6. Suggests clarifying questions to ask the interviewer
7. Generates a talk-through script for explaining your solution

Supported languages: Python, Java, C++, C#, JavaScript, TypeScript, Go, Kotlin, Swift, Rust, Ruby, PHP, Dart, Scala, Elixir, Erlang, and Racket. Set your preferred language in settings.

System Design Interviews

TopCoder comes with pre-built answers for all famous system design problems (Design Uber, Design Twitter, Design a URL Shortener, etc.) baked directly into the app — no AI latency, instant results. For custom topics, TopCoder generates full system design answers using AI. You can also save your own architecture notes, capacity estimation formulas, and design patterns to the knowledge base. During the interview, TopCoder:

• Instantly serves pre-built answers for well-known system design questions — zero delay
• Generates AI-powered solutions for any custom system design topic
• Pulls relevant notes from your knowledge base in real time
• Helps you articulate trade-offs between approaches
• Provides capacity estimates and back-of-the-envelope calculations
• Suggests follow-up points based on conversation context

Behavioral Interviews

Upload your STAR stories and talking points organized by competency. When the interviewer asks "Tell me about a time...", TopCoder searches your knowledge base and surfaces the most relevant story, structured in STAR format (Situation, Task, Action, Result).

Plans & Pricing

All plans include the same AI features: screenshot analysis, live transcription, auto-detection, knowledge base, and talk-through script. The only difference is the number of interview sessions.

Each interview session lasts up to 2 hours and supports up to 80 AI calls. One credit is consumed when you start a session.

Referrals

Share your referral code with friends to earn free interview credits. You need to have purchased a plan to unlock referrals. Here's how it works:

1. Purchase any plan to unlock your referral code on the Referrals page.
2. Share it with friends who are preparing for interviews.
3. When they apply your code and make their first purchase (minimum $5), they get +1 bonus interview and you earn referral credits.

Referral Rewards

Referral codes expire after 7 days but can be regenerated at any time from your dashboard.

Web Dashboard

The web dashboard at topcoder.app/dashboard lets you manage your account, purchase credits, and track usage.

Troubleshooting

Microphone or Screen Recording permission denied

Go to System Settings > Privacy & Security and enable TopCoder.App under both Microphone and Screen Recording. Restart the app after granting permissions.

Audio not being captured

Make sure listening is enabled (Ctrl+Shift+M). If your interviewer's voice isn't being captured, check that your video call's audio is playing through the default output device. TopCoder captures system audio using ScreenCaptureKit, which requires the Screen Recording permission.

App not invisible during screen share

This should not happen if the app launched correctly. Try quitting and relaunching TopCoder.App. If the issue persists, ensure you're running macOS 14 or later and that no accessibility tools are overriding window behavior.

Session expired or "No active session"

Each interview session has a 2-hour maximum duration. If your session expires mid-interview, start a new one (this consumes another credit).

Credits not appearing after purchase

Credits are added automatically after Stripe confirms your payment. This usually takes a few seconds. Try refreshing your dashboard. If credits still don't appear after a few minutes, contact support@topcoder.app.

Knowledge base files not saving

Check that your file is a supported type (PDF, DOCX, TXT, MD, RTF, PNG, JPG, HEIC) and within the 2 MB size limit. Also verify you haven't exceeded the per-project file limit.