12 Filters for Finding Mispriced Markets on Polymarket (Free Checklist)

linderroger-eng — Tue, 02 Jun 2026 18:09:17 +0000

Most Polymarket traders browse markets the same way everyone else does — scrolling through trending topics, picking sides based on gut feelings, and wondering why they keep losing money. The traders who consistently profit do something different: they filter.

This post breaks down the 12 filters I use to identify mispriced markets before placing a single dollar. Not vague principles — specific signals you can check in under five minutes per market.

Why Mispricing Happens on Polymarket

Prediction markets are more efficient than most people think, but inefficiencies exist. They cluster around low-liquidity markets, fast-moving news cycles, and questions where the crowd has emotional rather than informational bias. Your job is to find those pockets before the market corrects.

The 12 Filters

Filter 1: Liquidity Floor Check
Only trade markets with at least $5,000 in total liquidity. Below that, a few large bets can move prices dramatically, making your exit painful.

Filter 2: Resolution Criteria Clarity
Read the resolution criteria word-for-word. Ambiguous wording means contested resolutions or operator discretion. Pass on anything unclear.

Filter 3: Time-to-Resolution Efficiency
Calculate your annualized return. A market at 94¢ with 60 days to resolution yields ~12% annualized. The same market with 365 days yields ~6%. Capital efficiency matters.

Filter 4: News Lag Detection
Check when the market price last moved vs. when relevant news broke. If there's a lag, the market may still be catching up. Google News timestamps are your friend.

Filter 5: Base Rate vs. Market Price Divergence
Find the historical base rate for the event type. If the market price diverges from base rates by more than 10 points without a clear narrative reason, investigate.

Filter 6: Correlated Market Consistency
Polymarket often runs multiple related markets simultaneously. Check that implied probabilities are internally consistent. Arbitrage hides in the gaps.

Filter 7: Volume Trend vs. Price Trend
A price moving up on declining volume is a weak signal. Rising price on rising volume has real conviction behind it.

Filter 8: Crowd Sentiment Proxy
Check Twitter/X for the prevailing narrative. If sentiment is overwhelmingly one-sided but the market is balanced, that asymmetry is worth probing.

Filter 9: Operator Track Record
Political and sports markets tend to resolve cleanly. Novel or complex conditional markets carry more operator risk. Check the market creator's history.

Filter 10: Kelly Criterion Sanity Check
Before sizing any position: Edge / Odds = Optimal Fraction. If your edge is 5% betting YES at 70¢, your Kelly fraction is ~7% of bankroll. Never exceed full Kelly.

Filter 11: Whale Wallet Activity
Polymarket is on-chain. Use Polygonscan or whale-tracking tools to see where large traders are positioned. Smart money isn't always right, but it's worth knowing.

Filter 12: Reversion Potential Timing
Markets frequently overcorrect on dramatic news, then revert over 24-72 hours. The reversion window is often where the edge lives.

How to Use These Filters Together

Run each market through all 12. You're looking for markets that pass at least 8-9 — that's your signal a genuine edge exists. The more filters a market fails, the more you should question whether you have informational advantage or just conviction.

The discipline is in the checklist, not the instinct.

Get the Full Checklist (Free)

I've formatted all 12 filters into a one-page checklist you can use before every Polymarket trade. Includes scoring guidelines, a resolution risk rubric, and the Kelly formula pre-filled.

👉 Download the Free Polymarket Edge Checklist

No email required. Use it, share it, and if it helps you find your first mispriced market — come back and let me know in the comments.

Polymarket trading involves real financial risk. This article is for educational purposes only.

I Built a REST API That Wraps USASpending.gov, SAM.gov and Grants.gov Into One Clean Endpoint

linderroger-eng — Tue, 02 Jun 2026 16:45:48 +0000

The Problem

Working with US government spending data is painful.

USASpending.gov requires complex POST payloads with nested JSON filters
SAM.gov needs API key registration and has rate limits
Grants.gov has its own completely different format

Every developer building govtech tools has to figure all this out from scratch. I got tired of it.

What I Built

A single REST API that normalizes all three sources into clean, consistent JSON responses.

One GET request. Real data. No auth headaches.

# Get top DoD contracts right now
curl "https://government-contracts-grants-api1.p.rapidapi.com/contracts?agency=Department%20of%20Defense&limit=5" \
  -H "X-RapidAPI-Key: YOUR_KEY" \
  -H "X-RapidAPI-Host: government-contracts-grants-api1.p.rapidapi.com"

Real Data Example

Here is what comes back — actual federal contracts, not mock data:

{
  "count": 3,
  "source": "USASpending.gov",
  "contracts": [
    {
      "contract_id": "HT940216C0001",
      "recipient": "HUMANA GOVERNMENT BUSINESS INC",
      "agency": "Department of Defense",
      "amount_usd": 51269205263.03,
      "start_date": "2016-08-01",
      "end_date": "2025-12-31"
    },
    {
      "contract_id": "DENA0003525",
      "recipient": "NATIONAL TECHNOLOGY & ENGINEERING SOLUTIONS OF SANDIA, LLC",
      "agency": "Department of Energy",
      "amount_usd": 42370311400.75,
      "start_date": "2017-01-18",
      "end_date": "2027-04-30"
    }
  ]
}

Endpoints

GET /contracts — Filter by agency, amount, keyword
GET /grants — Federal grants from USASpending.gov
GET /agencies — All federal agencies with budget data

Use Cases

GovCon intelligence — Track competitor contract wins in real time

Business development — Identify which agencies are spending in your sector

Grant research — Find federal grants filtered by agency and dollar amount

Compliance tools — Build apps on top of real procurement data without scraping

Market analysis — Analyze federal spending trends across agencies

Why Not Just Use The Raw APIs?

You can. But:

USASpending requires a POST with nested filter objects just to search
You need separate auth flows for each source
Response formats are completely different across sources
No single query spans all three datasets

This API handles all of that so you can focus on building.

Free Tier Available

Free tier includes 100 requests/month — enough to prototype and test.

Find it on RapidAPI: Government Contracts & Grants API

Happy to add endpoints based on what people actually need — drop a comment below.

DEV Community: linderroger-eng