| name | polymarket-mert-sniper |
| description | Near-expiry conviction trading on Polymarket. Snipe markets about to resolve when the odds are heavily skewed. Filter by topic, cap your bets, and only trade strong splits close to deadline. |
| metadata | {"author":"Simmer (@simmer_markets)","version":"1.2.2","displayName":"Mert Sniper","difficulty":"advanced","attribution":"Strategy inspired by @mert — https://x.com/mert/status/2020216613279060433"} |
Mert Sniper
Near-expiry conviction trading on Polymarket. Snipe markets about to resolve when the odds are heavily skewed.
Strategy by @mert — filter by topic, cap your bets, wait until near expiry, and only trade strong splits.
This is a template. The default logic (expiry + split filter) gets you started — remix it with your own filters, timing rules, or market selection criteria. The skill handles all the plumbing (market discovery, trade execution, safeguards). Your agent provides the alpha.
When to Use This Skill
Polymarket only. All trades execute on Polymarket with real USDC. Use --live for real trades, dry-run is the default.
Use this skill when the user wants to:
- Trade markets that are about to resolve (last-minute conviction bets)
- Filter by topic (e.g. only SOL/crypto markets)
- Cap bet size (e.g. never more than $10)
- Only trade when odds are strongly skewed (e.g. 60/40 or better)
- Run an automated expiry-sniping strategy
Setup Flow
-
Install the Simmer SDK
pip install simmer-sdk
-
Ask for Simmer API key
- Get it from simmer.markets/dashboard -> SDK tab
- Store in environment as
SIMMER_API_KEY
-
Ask for wallet private key (required for live trading)
- This is the private key for their Polymarket wallet (the wallet that holds USDC)
- Store in environment as
WALLET_PRIVATE_KEY
- The SDK uses this to sign orders client-side automatically — no manual signing needed
-
Ask about settings (or confirm defaults)
- Market filter: Which markets to scan (default: all)
- Max bet: Maximum per trade (default $10)
- Expiry window: How close to resolution (default 2 minutes)
- Min split: Minimum odds skew (default 60/40)
-
Save settings to config.json or environment variables
Configuration
| Setting | Environment Variable | Default | Description |
|---|
| Market filter | SIMMER_MERT_FILTER | (all) | Tag or keyword filter (e.g. solana, crypto) |
| Max bet | SIMMER_MERT_MAX_BET | 10.00 | Maximum USD per trade |
| Expiry window | SIMMER_MERT_EXPIRY_MINS | 2 | Only trade markets resolving within N minutes |
| Min split | SIMMER_MERT_MIN_SPLIT | 0.60 | Only trade when YES or NO >= this (e.g. 0.60 = 60/40) |
| Max trades/run | SIMMER_MERT_MAX_TRADES | 5 | Maximum trades per scan cycle |
| Smart sizing % | SIMMER_MERT_SIZING_PCT | 0.05 | % of balance per trade |
Quick Commands
python scripts/status.py
python scripts/status.py --positions
API Reference:
- Base URL:
https://api.simmer.markets
- Auth:
Authorization: Bearer $SIMMER_API_KEY
- Portfolio:
GET /api/sdk/portfolio
- Positions:
GET /api/sdk/positions
Running the Skill
python mert_sniper.py
python mert_sniper.py --live
python mert_sniper.py --filter solana
python mert_sniper.py --expiry 5
python mert_sniper.py --live --smart-sizing
python mert_sniper.py --positions
python mert_sniper.py --config
python mert_sniper.py --no-safeguards
How It Works
Each cycle the script:
- Fetches active markets from Simmer API (optionally filtered by tag/keyword)
- Filters to markets resolving within the expiry window (default 2 minutes)
- Checks the price split -- only trades when one side >= min_split (default 60%)
- Determines direction: backs the favored side (higher probability)
- Safeguards: Checks context for flip-flop warnings, slippage, market status
- Execution: Places trade on the favored side, capped at max bet
- Reports summary of scanned, filtered, and traded markets
Example Output
🎯 Mert Sniper - Near-Expiry Conviction Trading
==================================================
[DRY RUN] No trades will be executed. Use --live to enable trading.
Configuration:
Filter: solana
Max bet: $10.00
Expiry window: 2 minutes
Min split: 60/40
Max trades: 5
Smart sizing: Disabled
Safeguards: Enabled
Fetching markets (filter: solana)...
Found 12 active markets
Markets expiring within 2 minutes: 2
SOL highest price on Feb 10?
Resolves in: 1m 34s
Split: YES 72% / NO 28%
Side: YES (72% >= 60%)
[DRY RUN] Would buy $10.00 on YES
Summary:
Markets scanned: 12
Near expiry: 2
Strong split: 1
Trades executed: 0
[DRY RUN MODE - no real trades executed]
Troubleshooting
"No markets found"
- Check your filter -- try without a filter first
- Markets may not be available (check simmer.markets)
"No markets expiring within window"
- Increase expiry window:
--expiry 10 (10 minutes)
- Or run more frequently (cron every minute)
"Split too narrow"
- Lower the min split:
--set min_split=0.55
- This trades more often but with less conviction
"Resolves in: 17h" on 15-min markets
- Polymarket's
endDate is the event-level end-of-day, not the individual market close time
- For 15-min crypto markets (e.g. "BTC Up or Down - Feb 8, 11PM ET"), the actual close time is in the question text but not in the API
- This is a Polymarket data limitation — widen the expiry window (
--expiry 1080) as a workaround, or use the split filter to find conviction opportunities regardless of timing
"External wallet requires a pre-signed order"
WALLET_PRIVATE_KEY is not set in the environment- The SDK signs orders automatically when this env var is present — no manual signing code needed
- Fix:
export WALLET_PRIVATE_KEY=0x<your-polymarket-wallet-private-key>
- Do NOT attempt to sign orders manually or modify the skill code — the SDK handles it
"Balance shows $0 but I have funds on Polygon"
- Polymarket V2 (live 2026-04-28) uses pUSD (PolyUSD, 1:1 backed by USDC.e). If your wallet holds USDC.e, migrate at simmer.markets/dashboard with one click (~30s)
- If you bridged native USDC (Circle), swap to USDC.e first, then migrate to pUSD
- Full migration guide: docs.simmer.markets/v2-migration
"API key invalid"
- Get new key from simmer.markets/dashboard -> SDK tab
