Polymarket Reverse Arbitrage Bot

TypeScript automation for my Polymarket reverse strategy on 15-minute BTC/ETH Up or Down markets.

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My Polymarket account

Profile	@odahoa
Username	odahoa
Proxy wallet	0xe2511c9e41c5e762887e538b1d6e7221807aa237
Markets	btc-updown-15m, eth-updown-15m

All activity, positions, and PnL live on my profile:
https://polymarket.com/@odahoa?tab=activity

This bot trades from that account — it automates what I already do manually. It is not copy trading and does not watch any other wallet.

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Overview

Polymarket runs 15-minute windows like:

Bitcoin Up or Down — 1:45PM–2:00PM ET

Each window has two tokens:

Token	Wins when
Up	Price at end ≥ price at start
Down	Price at end < price at start

Winning tokens pay $1.00. Losing tokens pay $0.00.

My strategy — the reverse bot — posts limit BUY orders on both sides every window:

1. Cheap reversal side (7–10¢) on the underdog outcome
2. Expensive hedge side (90–95¢) on the favorite outcome

That is the same pattern visible on my activity tab: round limit prices (7¢, 8¢, 10¢ … 95¢), 20–90 shares per fill, no sells — hold to resolution.

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Why "reverse"?

Early in a window, price often trends one way:

BTC pumps in first 10 minutes
  → Up token   ~90–97¢  (favorite)
  → Down token ~3–10¢   (underdog)

The crowd prices the underdog as nearly dead. The reverse bet is: it flips before the window closes.

Leg	Outcome	Entry	If it wins
Reverse	Underdog	7–10¢	~10–14×
Hedge	Favorite	90–95¢	~5–11%

Only one side pays $1 per window. I run both legs because:

• Cheap fills are rare but pay huge when they hit.
• Hedge fills are smaller profit but hit more often.
• Over hundreds of windows, a few reversals cover many losses.

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How I trade (manual → bot)

From my account history:

Pattern	Detail
Markets	BTC & ETH 15m Up/Down only
Order type	Limit BUY only — never sell
Cheap leg	Fills at 7–10¢ (sometimes 5–25¢) on underdog
Hedge leg	Fills at 90–95¢ on favorite
Both sides	Same window — e.g. Down @ 95¢ and Up @ 15¢
Size	20–90 shares per order

The bot replaces hand-placing every limit order each window.

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Bot logic

Every 5 seconds (configurable):

1. Scan active btc-updown-15m / eth-updown-15m markets
2. Load Up & Down order books (CLOB API)
3. Underdog  = outcome with lower best ask
4. Favorite  = the other outcome
5. Post limit BUYs on underdog  @ 7¢, 8¢, 9¢, 10¢
6. Post limit BUYs on favorite  @ 90¢–95¢  (if hedge enabled)
7. Skip price levels already posted this session

Cheap leg — underdog @ 7–10¢

Down best ask = 4¢  →  bot bids 7¢, 8¢, 9¢, 10¢ on Down

If Down reverses and wins:

90 shares × 8¢  =  $7.20 in
90 shares × $1  =  $90.00 out   →  +$82.80 (~1,150%)

Hedge leg — favorite @ 90–95¢

Up best ask = 97¢  →  bot bids 90¢–95¢ on Up

If Up holds and wins:

52 shares × 95¢  =  $49.40 in
52 shares × $1   =  $52.00 out  →  +$2.60 (~5%)

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Example window

Market: Bitcoin Up or Down — 1:45–2:00 PM ET
BTC pumped early → Up favored, Down cheap

Token	Book	Bot posts
Up (favorite)	ask 97¢	BUY limits @ 90–95¢
Down (underdog)	ask 4¢	BUY limits @ 7–10¢

Result	Cheap leg	Hedge leg
Up wins	Down → $0	Up → small profit
Down reverses	Down → big profit	Up → $0

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Return table

Buy price	Payout	Return if win
7¢	$1.00	+1,329%
8¢	$1.00	+1,150%
9¢	$1.00	+1,011%
10¢	$1.00	+900%
95¢	$1.00	+5%

Most 7–10¢ bets go to zero. Edge comes from occasional reversals at high multiples.

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Quick start

git clone https://github.com/nidichaogequ/polymarket-reverse-arbitrage-bot
cd reverse-bot
npm install
cp .env.example .env
npm start          # dry-run: logs orders, no submission

Go live on @odahoa

DRY_RUN=false
PRIVATE_KEY=0x...                                           # account signing key
FUNDER_ADDRESS=0xe2511c9e41c5e762887e538b1d6e7221807aa237   # @odahoa proxy wallet
SIGNATURE_TYPE=2

SIGNATURE_TYPE	Use for
0	EOA / MetaMask
2	Gnosis Safe proxy (typical Polymarket account)
3	POLY_1271 deposit wallet

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Config

Strategy

Variable	Default	Description
CHEAP_BUY_MIN	0.07	Low end of reversal bids
CHEAP_BUY_MAX	0.10	High end of reversal bids
CHEAP_ORDER_USDC	10	USDC per cheap limit order
ENABLE_EXPENSIVE_HEDGE	true	Post 90–95¢ favorite bids
EXPENSIVE_BUY_MIN	0.90	Low end of hedge bids
EXPENSIVE_BUY_MAX	0.95	High end of hedge bids
EXPENSIVE_ORDER_USDC	50	USDC per hedge limit order
MAX_SHARES_PER_ORDER	90	Max shares per order

Markets & timing

Variable	Default	Description
MARKET_SLUG_PREFIXES	btc-updown-15m,eth-updown-15m	Markets to scan
POLL_INTERVAL_MS	5000	Scan interval
MINUTES_BEFORE_CLOSE_MIN	0	Start trading N min into window
MINUTES_BEFORE_CLOSE_MAX	15	Stop trading N min before close

Trade only late window (when cheap tokens show up):

MINUTES_BEFORE_CLOSE_MIN=3
MINUTES_BEFORE_CLOSE_MAX=12

Safety

Variable	Default	Description
DRY_RUN	true	Log only — no real orders

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Project layout

reverse-bot/
├── src/
│   ├── index.ts           # main loop
│   ├── market-scanner.ts  # active 15m markets + books
│   ├── strategy.ts        # underdog/favorite + limit prices
│   ├── trader.ts          # CLOB order submission
│   └── config.ts
├── .env.example
└── package.json

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Commands

npm start      # run bot
npm run dev    # run with hot reload
npm run build  # compile TypeScript

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Risks

• Most cheap bids lose. 7–10¢ tokens frequently expire worthless.
• Limits may not fill. Bidding 7¢ when ask is 4¢ waits for sellers.
• Both legs can't both win. One side always goes to $0.
• Real money. Test with DRY_RUN=true first.

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Links

• My profile: https://polymarket.com/@odahoa
• My activity: https://polymarket.com/@odahoa?tab=activity
• Polymarket settings: https://polymarket.com/settings