The Practical Guide to Polymarket Copy Trading (No Fluff)

If you’ve spent any time on Polymarket, you know the frustration of watching a high-conviction trader move the market while you’re still fumbling with your wallet connection. You want to mirror their moves, but doing it manually is a losing game. That’s where a polymarket copy trading bot comes in. It’s not a magic money printer, but it is a way to automate the "follow-the-leader" aspect of prediction markets so you aren't chasing fills by hand.

Most people get tripped up by thinking this is an arbitrage tool. It isn't. If you’re looking for sub-millisecond execution to capture price discrepancies, a simple poll-based script won't cut it. This is about mirroring the strategy of a target address. If that trader jumps off a cliff, your bot will politely follow them down. You need to treat this as a tool for execution, not a replacement for your own research.

Here is how you actually set this up without nuking your wallet:

1. Environment Setup: Clone the repository and get your .env file sorted. Never, under any circumstances, commit your private keys to a public repo.
2. Target Selection: Identify the proxy address of the trader you want to mirror. If you only have a username, you’ll need to resolve that to a proxy address first.
3. Safety Rails: This is the part nobody talks about. You must set a COPY_MAX_ORDER_USD cap. If you don't, and your target trader decides to go "all-in" on a long-shot, your bot will drain your account trying to match them.
4. Execution: Run the bot using npm run dev to monitor the logs. Watch the output to ensure it’s actually picking up the target's activity before you move to a production environment.

The biggest failure mode I see is users setting the COPY_SIZE_MULTIPLIER too high. Start small—maybe 0.1—and observe the bot’s behavior over a few cycles. You want to see how it handles slippage and order matching before you let it handle significant capital.

That said, there’s a catch: latency. Because this bot uses a polling interval (COPY_POLL_INTERVAL_MS), you are inherently behind the target trader. If the market is moving fast, you will get worse fills than the person you are copying. You have to accept that you are paying a "convenience tax" for the automation.

If you are serious about building a more robust system, you’ll eventually need to move away from polling and toward a streaming architecture. But for getting started, this Polymarket trading bot typescript implementation is the most straightforward path.

Before you deploy, ask yourself: do you actually trust the target trader's long-term performance, or are you just chasing a recent win? If you don't have a thesis, the bot is just a faster way to lose money. Try this today with a tiny amount of capital and share what you find in the comments. Read our breakdown of advanced prediction market strategies next to see how to layer this with your own analysis.