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ExtraBrain is a desktop app, not a meeting bot joining the room. Keep session scope, prompts, and outputs in your control.
Desktop copilot for Mac & Windows
Free AI interview copilot that only you can see.
Get live transcription, screen-aware context, and AI answers during interviews and meetings. Choose local or cloud transcription, and use built-in ExtraBrain AI or connect your preferred provider.
Free for Mac & Windows · macOS 14+ on Apple Silicon & Intel · Pro from $9.99/mo
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Local Parakeet transcription Built-in ExtraBrain AI Bring OpenAI, Anthropic, Claude, or Codex
Live session
System design interview · live
14:02
ExtraBrain · live transcript Listening · 14:02
14:02:10Host Design a rate limiter for a public API with regional spikes and abusive bursts.
14:02:18You Should limits be per user, per IP, or per endpoint?
14:02:24Host Start with per-user and per-endpoint limits. We care about burst traffic and graceful fallback.
Answer · 2 sources · 0.6s
Start with token buckets at the edge for burst tolerance, then coordinate counters through
Redis or another distributed store. Call out fail-open vs fail-closed.
transcript · 14:02:10 transcript · 14:02:24
Saved facts
Rate limiter · public API
Burst traffic: edge token buckets
Tradeoff: fail-open vs fail-closed
Session memory
Live context
Transcript-aware answers, saved facts, and follow-ups while the call is still active.
How it works
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Click Start to run a 1-minute practice interview and see what ExtraBrain does while you talk.
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ExtraBrain Mobile · iOS and Android Your desktop session.
Your desktop session.
Your phone controls.
Ask a question, capture desktop context, or scroll your answer from your iPhone or Android phone. Keep ExtraBrain open on your computer, where transcription, capture, and answers happen.
Scan your computer’s pairing code and approve your phone to connect. No separate ExtraBrain account required.
Controller
Controls for the ExtraBrain session.
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How to pair
- 1In ExtraBrain, open Settings and choose System › Remote.
- 2Tap Pair a phone.
- 3Scan the constellation with this phone.
The camera reads pairing codes and takes photos you choose to attach.
Controller
Sample session. These controls stay on this phone.
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Suggested follow-ups
What should we decide next?
Summarize the last few minutes.
List the open questions.
Chat help
Send a question or choose a quick action for the Assistant chat. Answers appear in ExtraBrain on your computer.
Use + to take or choose a photo. Add a question, or send photos on their own to add context.
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Scan constellation
Pairing scans the constellation that ExtraBrain shows on your computer. Get the app on your phone to pair, or explore the sample session here.
Compatibility
Works invisibly across the interview and meeting platforms people actually use.
ExtraBrain is designed to stay hidden from screen sharing and screen recording on major video call tools and coding interview environments, while remaining available on your own Mac or Windows PC. Always follow the rules of the interview, employer, school, meeting, or platform.
Maya Chen
Jordan Lee
End Ask
System Design
What should I say?
Rate limiter for a public API
Clarify the scope first, then pick an algorithm that tolerates bursts.
- Limit per API key, with tighter caps on expensive endpoints.
- A token bucket absorbs short spikes and keeps the average rate.
- Keep counters in Redis so every gateway shares state.
Follow-ups
ExplainAsk clarifying questionWhat should I say?Recap
Manage Ask anything, or type / for actions...
Zoom
Google Meet
Microsoft Teams
Cisco Webex
Amazon Chime
Lark / Feishu
Slack Huddles
Discord
HackerRank
CoderPad
Codility
CodeSignal
Built for live coding interviews, LeetCode-style prompts, system design rounds, behavioral interviews, product interviews, data and ML interviews, consulting cases, lectures, and research calls.
Overview
An invisible AI copilot for interviews, meetings, lectures, and research.
ExtraBrain turns live audio, transcript text, screenshots, and selected context into organized prompts, answer structures, and session memory while keeping provider choice, costs, and privacy boundaries visible.
From download to live support in three steps.
Keep the setup path simple: install the desktop app, choose local or cloud transcription, use built-in ExtraBrain AI or connect your preferred provider, and rehearse once before a real interview, meeting, or lecture.
Start the desktop app
Download the latest release, open ExtraBrain before the interview or meeting, and confirm microphone, transcription, and provider settings.
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Built-in ExtraBrain AI or your preferred provider
Use built-in ExtraBrain AI, or connect OpenAI, Anthropic, custom OpenAI-compatible endpoints, Claude Subscription, or Codex Subscription modes.
Follow the live signal
Use transcript-aware prompts for coding interviews, system design rounds, product meetings, lectures, and research calls.
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Live interview and meeting context
Capture transcripts, prompts, screenshots, constraints, and follow-up questions while the call is still moving.
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Interview answers with structure
Turn coding, system design, and behavioral prompts into clarifying questions, baselines, tradeoffs, and follow-up points.
Leave with useful context
Generate summaries, action items, edge cases, unresolved risks, and post-answer feedback before the session context fades.
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Your session context, ready to review
Keep transcripts, prompts, screenshots, and notes on your computer in a fully local setup, or explicitly send selected content to external providers when you choose them.
Use cases
Designed for moments where context moves faster than notes.
Pick a situation to see what ExtraBrain hears and what it hands you while the moment is still happening.
The prompt just landed, and the clock is running.
What ExtraBrain hears
- Given a list of meeting times, return the minimum number of rooms you need.
- Assume up to a hundred thousand meetings.
- Can a meeting start right when another one ends?
Edge cases and a baseline
Minimum rooms for n intervals, n up to 105
- Empty list: return 0
- Touching ends, like [1, 3] and [3, 5], can share a room
- Input may arrive unsorted
- 105 meetings rules out comparing every pair
BaselineSort starts and ends, then sweep with two pointers O(n log n)
- Engineers
- Students
They want a design, and they want it now.
What ExtraBrain hears
- Design a rate limiter for a public API that sees regional traffic spikes.
- Should limits apply per user, per API key, or per endpoint?
- Start with per-key limits. We care most about burst traffic.
Components and tradeoffs
- Client
- API gateway
- Rate limitertoken bucket per key
- Redis
Fail openThe API stays up, but a burst can overload it
Fail closedThe backend is protected, but good traffic gets dropped
Ask nextShould expensive routes like search get a separate cap?
- Engineers
Decisions fly by faster than anyone writes them down.
What ExtraBrain hears
- Bursts got past the gateway, and checkout timed out for twenty minutes.
- I'll ship per-key rate limits behind a feature flag by Thursday.
- Billing also saw 429 errors on paid plans this week.
Decisions, owners, and dates
- DecidedPer-key rate limits, behind a feature flagYou · Thu
- ActionWrite the EU spike postmortemYou · Fri
- ActionConfirm paid-plan limits with billingYou · today
- OpenWhy did 429s hit paid plans?Billing
- PMs
- Founders
- Engineering leads
The customer just said the exact quote you need.
What ExtraBrain hears
- Honestly, every Friday someone exports everything to CSV.
- Our ops lead spends half a day fixing the columns.
- What happens if that report is late?
- Then finance can't close the week.
Pain points with quotes
"Every Friday someone exports everything to CSV."
"Then finance can't close the week."
Roadmap noteScheduled exports with saved column mappings
- Research teams
- PMs
- Founders
The lecturer just skipped two steps.
What ExtraBrain hears
- A B-tree keeps every node at least half full.
- So the height stays logarithmic, even with millions of keys.
- And each node fits one disk page, which is why databases love them.
Review flashcards
QWhy does a B-tree stay shallow with millions of keys?
AEvery node stays at least half full, so height grows with log n.
- Students
Agent Skills and CLI
Put your session context to work with Claude Code and Codex.
ExtraBrain Skills connect your coding agent to the sessions you saved: prepare before an interview, then review it or pull out what you promised after the call. Pick a skill to watch it run.
- Before the call
- During the call ExtraBrain listens and helps live The transcript, screenshots, and answers are saved on your computer.
- After the call
Also included: check grammar, review communication, unresolved follow-ups, system design prep.
❯ Prep me for Thursday's backend onsite at a payments company. My resume is in ./prep
● Skill(extrabrain-prepare-interview)
⎿ Successfully loaded skill
● Bash(extrabrain --json capabilities)
⎿ {"code":0,"data":{"apiVersion":3,"documents":{"import":true,"search":true}
● Bash(extrabrain --json documents import --group "Payments backend onsite prep" -- brief.md coding.md payments-api.md stories.md cheatsheet.md)
⎿ {"code":0,"data":{"batchId":"imp_7Q2M9X","accepted":5,"rejected":0,"groupId":"grp_4T8K"
● Bash(extrabrain --json profiles pin system prf_system_design)
⎿ {"code":0,"data":{"profileSelection":{"mode":"pinned","label":"System Design"}
Ran 3 shell commands
Ready for Thursday: 5 study files are in ExtraBrain
- Group Payments backend onsite prep: brief, coding patterns, an idempotent payments API case, 6 STAR stories from your resume, and a cheat sheet
- Likely focus: idempotency keys, safe retries, and ledger consistency
- Profile System Design pinned for the interview
Next, I can:
- quiz you on the payments API case, one question at a time
- tighten your "biggest failure" story
✻ Worked for 48s
❯ Review my system design interview from this morning
● Skill(extrabrain-review-interview)
⎿ Successfully loaded skill
● Bash(node scripts/read-session.mjs find system design)
⎿ 1 match: System design interview · Tue 10 Nov · 14 min · ses_01JC8Z4K2V
● Bash(node scripts/read-session.mjs read ses_01JC8Z4K2V)
⎿ --- System design interview · 46 transcript lines · 4 detected questions
Ran 2 shell commands
Interview review · System design interview
Tue 10 Nov · 14 min · system design · 4 questions · read all 46 transcript lines
Overall: you scoped the problem before designing, and that set up the whole round. Commit to a decision on failure modes instead of listing both sides.
Strongest moments
- You asked how limits should apply (00:19, rate limiter scope). It turned a vague prompt into per-key buckets.
- You raised the outage case yourself (00:41, limiter store down). Interviewers look for this.
Fix these first
1. Pick fail open or fail closed, then defend it (00:47, store outage)
Say instead: "I'd fail open for reads so the API stays up, fail closed for writes, and page us if the store is down for more than [N] seconds."
Next, I can:
- rehearse the outage question with you and give feedback
✻ Worked for 11s
❯ What did I promise in today's API reliability sync?
● Skill(extrabrain-extract-action-items)
⎿ Successfully loaded skill
● Bash(extrabrain --json sessions list --limit 5)
⎿ {"code":0,"data":{"items":[{"id":"ses_01JC8Z4K2V","title":"API reliability sync","startedAt":"2026-11-09T10:42:04Z"
● Bash(extrabrain --json sessions get ses_01JC8Z4K2V)
⎿ {"code":0,"data":{"sessionId":"ses_01JC8Z4K2V","snapshot":"rev-4","counts":{"transcripts":8
● Bash(extrabrain --json sessions transcripts --limit 200 ses_01JC8Z4K2V)
⎿ {"code":0,"data":{"items":[{"source":"system","speaker":"Maya Chen","text":"Thanks for joining
● Bash(extrabrain --json sessions insights ses_01JC8Z4K2V)
⎿ {"code":0,"data":{"items":[{"kind":"summary","text":"An API reliability sync with Maya
● Bash(extrabrain --json sessions analyses list ses_01JC8Z4K2V)
⎿ {"code":0,"data":{"items":[{"title":"EU traffic spike follow-up","profile":"Meeting"
Ran 5 shell commands
Your action items from API reliability sync (today, 10:42 AM, with Maya Chen)
1. Ship per-key rate limits behind a feature flag · due Thursday
"I'll ship per-key rate limits behind a feature flag by Thursday." 0:04
Next: open the gateway PR with the flag off, then enable it in EU first.
2. Write the EU traffic spike postmortem · due before Friday's review
"I'll write it up and share it before Friday's review." 0:07
Next: draft the timeline of the 20-minute checkout outage.
3. Confirm paid-plan limits with billing · due today
"I'll check with billing today and confirm the plan limits." 0:10
Next: send billing the 429 counts per plan before you talk.
Not yours: Maya owns the Tuesday regroup.
✻ Worked for 9s
Install the skills
npx skills add ExtraBrainApp/ExtraBrain-skills Review skills only read your sessions, through the local CLI, and never change them. Turn off CLI access in Settings anytime.
Trust and control
Choose how your data is processed.
Session history is stored on your computer. AI and transcription processing depend on the providers you choose. Review analytics sharing and connected apps too. On-device AI is available as an advanced option on supported Macs.
- Capture Microphone and system audio Recorded by the desktop app, not a meeting botScreenshots you take Only the regions you capture
- Transcription NVIDIA Parakeet Runs locally on your computerDeepgram Optional, with your own key
- AI answers Gemma on-device · Advanced Supported Mac direct-download buildsExtraBrain AI or your preferred provider Built-in AI credits or your provider’s billing
- History Transcripts, notes, saved facts Stored on your computer until you delete them
Your model choice stays yours
The app does not force a single hosted AI vendor. Use built-in ExtraBrain AI, or connect the provider subscriptions, accounts, or API keys you trust.
Use it within the rules
Interview and workplace policies vary. ExtraBrain should support your thinking, notes, and preparation without misrepresenting your skills.
ExtraBrain should support your thinking, notes, and preparation. You are still responsible for following interview, workplace, and platform policies.Interview policy reminder
Pricing structure
Free to start. Pro from $9.99/month, or try it free for 14 days.
The app is free, with local or cloud transcription and your choice of AI provider. Every paid plan unlocks the same Pro tools; Monthly, Yearly, and the Job Search Pass also include ExtraBrain AI credits, while Lifetime does not.
Interviewing in the next 3 months? The $29 Job Search Pass gives you 90 days of Pro, one payment, no renewal.
Not sure yet? Try Pro free for 14 days, no card needed.
Bought here? Paste the license key from your email into Settings → Plan & Billing (how to activate). Mac App Store users buy inside the app.
Free
Free desktop app, live transcription, screen context, and your own provider connections.
Always free
- Download and use the desktop app on Mac or Windows
- Connect OpenAI, Anthropic, Claude, Codex, or a compatible provider; provider usage is billed separately
- Locally stored transcripts, prompts, screenshots, notes, and session context
- Local Parakeet transcription and optional Deepgram setup
- Help center, setup, privacy, and troubleshooting guides
Pro
Every paid plan unlocks the same Pro features. Monthly, Yearly, and the Job Search Pass also include ExtraBrain AI credits; Lifetime does not.
- Everything in Free
- Automatic answers when ExtraBrain detects a question or topic
- Custom profiles with reusable prompt guidance and your own chat actions
- Full post-session summaries
- Top-tier models with your own keys, such as Claude Opus and OpenAI's flagship models
- 1,000 ExtraBrain AI credits a month with Monthly, Yearly, and the Job Search Pass; Lifetime includes no credits
- Purchase and activate from Settings → Plan & Billing inside the app
Enterprise
Policy, deployment, privacy, and workflow support for teams.
Custom
- Team rollout planning
- Responsible-use and policy guidance
- Security and deployment review
- Custom workflow support for team requirements
Comparing with other interview assistants? See how pricing and data handling differ.
FAQ
Common questions about ExtraBrain.
Short answers about pricing, privacy, AI providers, supported platforms, and responsible use.
See all questionsWhat is ExtraBrain?
ExtraBrain is a free desktop AI interview and meeting copilot. It provides live transcription, screen-aware context, structured prompts, question generation, built-in ExtraBrain AI, and a desktop window designed for private live workflows. It is available for Mac and Windows, with Linux planned.
Is ExtraBrain free?
Yes. ExtraBrain is free to download and use, with no session limits. ExtraBrain Pro is $9.99/month, $79/year, a $29 Job Search Pass for 90 days, or $149 Lifetime, and a 14-day Pro trial is free with no credit card. Pro Monthly, Pro Yearly, and the Job Search Pass include 1,000 ExtraBrain AI credits each month, and the 14-day trial includes 500. Lifetime unlocks every Pro feature but does not include ExtraBrain AI credits. Pro adds automatic answers, custom profiles, full post-session summaries, and top-tier models with your own keys.
Does ExtraBrain Lifetime include AI credits?
No. Lifetime is a one-time $149 purchase that unlocks every Pro feature permanently, but it does not include ExtraBrain AI credits. Pro Monthly, Pro Yearly, and the Job Search Pass include 1,000 ExtraBrain AI credits each month, and the 14-day trial includes 500.
What platforms does ExtraBrain support?
ExtraBrain is available for Mac and Windows. On Mac it needs macOS 14 Sonoma or later, on Apple Silicon Macs such as M1, M2, M3, and M4, or on Intel Macs. Linux is planned, not a current release target.
Which AI providers does ExtraBrain support?
ExtraBrain supports built-in ExtraBrain AI and provider access you control: OpenAI, Anthropic, custom OpenAI-compatible endpoints, Claude Subscription, and Codex Subscription modes.
Does ExtraBrain collect user data?
ExtraBrain is designed as a desktop app. With local Gemma 4 and local Parakeet transcription, transcription and AI prompts can stay on your computer. Cloud AI and transcription services receive the context they process. Analytics sharing and connected apps are separate data paths; review their settings too.
Is using ExtraBrain in interviews allowed or considered cheating?
ExtraBrain is a tool, and you are responsible for following the policies of the company, interviewer, school, employer, or platform you are working with. Use it to support thinking, notes, accessibility, and preparation without misrepresenting your skills.
Can interviewers detect ExtraBrain on Zoom, Google Meet, or Microsoft Teams?
ExtraBrain is designed to stay hidden from screen sharing and screen recording on major meeting tools. You should still follow all interview, workplace, school, and platform rules.
Does ExtraBrain join the meeting as a bot?
No. ExtraBrain runs as a desktop app on your Mac or Windows PC rather than joining Zoom, Google Meet, Microsoft Teams, or other calls as another participant.
Ready when the conversation starts
Download the free app before the call starts.
ExtraBrain gives you a private live workspace for interview prompts, meeting notes, structured answers, and session context in a free desktop app you control. Upgrade only if you need Pro workflow features.
