Acedly AI on Coderpad: Real-Time AI for Live Coding Rounds (2026)
How Acedly AI works inside a Coderpad live coding round — reading the editor, generating idiomatic code in 12+ languages, staying hidden from screen sharing. What to verify before your Coderpad interview.
Devon Park
Head of Research, Acedly
What a Coderpad helper is — and why the bar is higher here
A Coderpad interview AI is a desktop tool that runs on your machine while you take a live coding interview on coderpad.io. It does three things at the same time, and it has to do all three well or it's worse than nothing:
- Read the problem statement from the Coderpad UI. Most interviewers paste a problem into the pad and stop talking. An audio-only assistant hears nothing and gives you nothing.
- Read the editor as you type. That way the helper can suggest the next line, catch a bug you just introduced, or refactor a brute-force solution into something idiomatic — all without you needing to copy-paste the code somewhere else first.
- Render the answer on a hidden surface that the interviewer can't see when they ask you to share your screen. This is the line between a tool that helps and a tool that fails you on the spot.
Coderpad is browser-only, runs custom JS hooks against a CodeMirror editor, and is the de-facto live coding sandbox for interviews. That makes it the hardest of the eight platforms Acedly verifies on, and the one where weak tools fall apart fastest.
Why Coderpad is the live coding sandbox in 2026
If you're interviewing for a software engineering role at a Western company in 2026, the odds you'll see Coderpad at some point in the loop are extremely high. Stripe, Robinhood, Reddit, Coinbase, Discord, and the bulk of Y Combinator graduates default to Coderpad for their live coding rounds. The pattern is familiar: the interviewer pastes a problem into the pad, asks you to think out loud, and watches the editor in real time as you type.
Two adjacent platforms do something different:
- HackerRank is heavier — used for senior and principal engineering loops because it has built-in test-case scaffolding, a real evaluator, and the ability to run hidden judge tests.
- LeetCode is for practice. You'll see it in your prep but rarely in a live recruiter round.
Coderpad sits in the middle: lighter than HackerRank, more interview-flavoured than LeetCode, and tuned specifically for the "watch the candidate code while they explain" interaction. That's why it's the one most interviewers default to — and why a Coderpad-specific AI tool has to be tuned to that specific interaction loop, not a generic "AI for coding interviews" plugin.
How a Coderpad helper actually works during a live round
The pipeline behind an AI-on-Coderpad helper looks deceptively simple. Each step has a latency budget, and each one has a different failure mode if you cheap out.
Reading the problem statement off the pad
The interviewer pastes a problem; the helper has roughly two seconds to extract it before you start talking. Doing this by audio alone fails — interviewers rarely read the whole problem aloud. Doing it by DOM scraping fails — Coderpad's CSP blocks browser extensions from reaching the editor reliably. The robust approach is to capture the application's own copy of the screen pixels (no external recording, no remote stream) and run a vision model that's been fine-tuned on code-editor screenshots. Acedly's median for problem-statement extraction is under 1.5 seconds end to end.
Reading the editor as you type
The harder job is keeping a real-time view of the editor as the candidate types. Coderpad's editor is a CodeMirror instance with custom event hooks that report typing cadence and paste events back to the interviewer. A helper that injects a script into the page is one CSP violation away from being detected. The same screen-pixel approach as above, sampled at roughly 4 Hz, gives you a clean copy of what's in the editor without ever touching the page.
Generating code in the language the interviewer chose
Coderpad supports more than thirty programming languages; the realistic set a serious helper covers fluently is twelve: Python, JavaScript, TypeScript, Java, C++, Go, Rust, Kotlin, Ruby, SQL, PHP, and Scala. The helper has to detect which language the interviewer picked from Coderpad's dropdown and stay in that language — switching to Python because the model is more comfortable in it is exactly the kind of mistake that gets a candidate caught.
Rendering on a stealth surface
The final output is drawn on a window that's excluded from screen-share APIs. On macOS that means setting NSWindowSharingNone; on Windows it means SetWindowDisplayAffinity(WDA_EXCLUDEFROMCAPTURE). If the helper is just another Electron window, the interviewer will see it the moment they ask you to share your screen — and almost every Coderpad round ends with a screen share at some point.
What makes Coderpad hard for AI tools (and what fails here)
Three classes of Coderpad helpers exist on the market right now, and two of them break in predictable ways:
- Browser-extension copilots. They try to read the editor by injecting JavaScript into the Coderpad page. Coderpad's content security policy blocks most of those injections, and the ones that get through trip Coderpad's telemetry the first time the candidate types. These tools demo well on the free playground and fail on the real "interview pad."
- OCR-only desktop tools. They take screenshots of the entire screen, OCR everything, and try to figure out where the editor is. Latency is bad (a full-screen OCR pass is several hundred ms before the model even runs), bugs in indentation and bracket detection are common, and any UI change on Coderpad's side breaks the parser overnight.
- Tools that capture pixels at the OS level on the candidate's own machine, paired with a vision model fine-tuned on code editors. This is the approach Acedly uses, and it's the only one that has held up across Coderpad UI revisions in 2025 and 2026.
The honest summary is that this is a hard problem, and most products in this space are not built for it. The "live coding sandbox" use case is a different engineering problem from "transcribe the recruiter's audio."
What Coderpad's anti-cheating signals actually check
Coderpad publishes some of this and the rest is easily reverse-engineered from the interviewer dashboard. The signals their "interview pad" mode tracks are, in roughly descending order of how much weight interviewers put on them:
- Paste events. When a candidate pastes more than a trivial amount of code into the editor, the interviewer sees a "Pasted X lines" annotation in their dashboard. This is the most common way candidates get caught using AI: they let the model write the answer in another window and paste it across.
- Focus changes and tab visibility. Coderpad logs when the candidate's tab loses focus and for how long. Frequent tab-aways during a hard problem are a soft signal — not a smoking gun, but enough to make an interviewer pay closer attention.
- Typing cadence. For Pro customers, Coderpad records a playback of the candidate's typing in real time. An interviewer can scrub through and see the exact rhythm — including pauses, deletions, and bursts. A candidate who suddenly types fifty lines of perfectly idiomatic Rust without a single backspace is also a signal.
The honest takeaway: pasting AI-generated code is detectable. Acedly does not paste — it shows you the answer in your local UI, on a window the interviewer can't see, and you type the answer yourself. That handles the paste-event signal cleanly. It does not, on its own, handle the typing cadence signal — that one is on you. Use the helper as a thinking aid, not a transcription target. Type the way you actually code: with hesitations, dead ends, and the occasional // wait, let me rename this.
Acedly vs. browser-extension copilots vs. ChatGPT in another tab vs. desktop OCR tools
Most candidates ask the wrong comparison question. The interesting one isn't "Acedly vs. some competitor." It's "an AI-on-Coderpad helper that's actually built for the use case versus the three alternatives that almost everyone tries first." Here is how those four options stack up on a real Coderpad round.
| Feature | Acedly | Browser-extension copilot | ChatGPT in another tab | Desktop OCR copilots |
|---|---|---|---|---|
| Reads the Coderpad editor in real time | Yes — OS-level pixels, ~4 Hz | Sometimes (CSP-dependent) | No (manual paste only) | Yes, but slow and brittle |
| Generates idiomatic code in 12+ languages | Yes — Python, JS, TS, Java, C++, Go, Rust, Kotlin, Ruby, SQL, PHP, Scala | Usually 1–2 languages | Yes (slow round trip) | Variable |
| Median end-to-end latency | ~98 ms | ~300–600 ms | Manual: several seconds | Several hundred ms (OCR pass) |
| Hidden from screen sharing | Yes — OS capture exclusion | No (just another browser tab) | No (just another window) | Partial — depends on the tool |
| Triggers Coderpad paste / focus tracking | No — never pastes for you | Sometimes (DOM injection) | Yes — paste required | No — but tab-away signal applies |
| Grounded in your résumé and the JD | Yes, by default | Rarely | Only if you paste them in | Sometimes |
The two columns most candidates underweight are the paste-tracking row and the latency row. ChatGPT in another tab is the most common choice and the most easily detected — paste a forty-line solution into Coderpad and the interviewer sees a banner reading "Pasted 40 lines" the second you do it. Browser-extension copilots advertise stealth they don't actually have on the live interview pad, and most of them are flagged inside a minute. The right baseline is a tool that never asks you to paste and is invisible at the OS level.
A 10-minute pre-interview checklist for a Coderpad round
If you have a Coderpad round on the calendar this week, here's what to run through in the ten minutes before the call. Most candidates discover their helper is broken when the interviewer is already on the line.
- Do a dry run on the free Coderpad playground. Go to coderpad.io, open a fresh sandbox, and run through the same actions you'd take in the real round — paste a problem from a friend, type a solution, share your screen with that friend, and ask them to confirm they cannot see Acedly. Do this once per machine, not once ever.
- Pick the language you're going to use, and configure Acedly to match. Don't use the helper to write Rust if you've never typed Rust. The most diagnostic tell on Coderpad is typing cadence — and you cannot fake fluency in a language you don't know.
- Set up your hotkey for second-monitor handoff. Acedly's UI is meant to live on a second screen or in a hidden window on your laptop. Decide which one before the call and bind a hotkey to bring it forward. Fumbling for the helper during a real interview is exactly when accidents happen.
- Open a code editor as a scratchpad. A separate VS Code window where you can talk through your reasoning out loud — naming variables, sketching the call graph — gives the interviewer something to watch and gives you a place to think that's separate from the helper. This is the single biggest "looks human" upgrade most candidates never make.
- Decide your ethical line in advance. Coderpad rounds vary wildly. Some companies are explicit that any tool is disqualifying; some treat it the same as having your résumé open in another tab. Decide before the call, not during it, what you're comfortable with — and remember that the helper's job is to keep you unstuck, not to write the answer.