Blog

Sports analytics, prediction markets, and building trading bots with Python.

wta model analysis

Why Our WTA Model Found 62 Edges This Week

WTA prediction model results: 41W-21L, 66.1% win rate. ML-powered fair value vs Polymarket prices.

cs2 model analysis

Why Our Counter-Strike 2 Model Found 60 Edges This Week

Counter-Strike 2 prediction model results: 33W-27L, 55.0% win rate. ML-powered fair value vs Polymarket prices.

polymarket referral promo

Polymarket Referral Codes & Bonuses: What's Real in May 2026 (and What's Not)

Honest guide to Polymarket referral codes, promo codes, and sign-up bonuses in May 2026. How the referral program actually works, which codes are real...

mlb model analysis

Why Our MLB Baseball Model Found 33 Edges This Week

MLB Baseball prediction model results: 16W-17L, 48.5% win rate. ML-powered fair value vs Polymarket prices.

atp model analysis

Why Our ATP Model Found 16 Edges This Week

ATP prediction model results: 6W-10L, 37.5% win rate. ML-powered fair value vs Polymarket prices.

kalshi referral promo

Kalshi Referral Code & Sign-Up Bonus: 2026 Guide

Honest 2026 guide to Kalshi's referral code and new-user sign-up bonus. How the referral program actually works, what the typical welcome offer is, which...

nhl model analysis

Why Our NHL Hockey Model Found 8 Edges This Week

NHL Hockey prediction model results: 5W-3L, 62.5% win rate. ML-powered fair value vs Polymarket prices.

nba model analysis

Why Our NBA Basketball Model Found 3 Edges This Week

NBA Basketball prediction model results: 0W-3L, 0.0% win rate. ML-powered fair value vs Polymarket prices.

polymarket kalshi comparison

Polymarket vs Kalshi Sign-Up Bonuses Compared (2026)

Honest 2026 comparison of Polymarket vs Kalshi sign-up bonuses, referral programs, and new-user offers. How each platform's promotion actually works, the...

results weekly trading

Week 21 Results: 117W-107L, +$29.29

ZenHodl week 21 live trading results across 8 sports. 52.2% win rate on 224 trades.

polymarket legality kalshi

Is Polymarket Legal in the US? The 2026 Answer

Is Polymarket legal for US users in 2026? Full breakdown of the 2022 CFTC settlement, the 2024 DOJ raid, the current geo-block, what US-based traders can...

kalshi sign-up tutorial

How to Sign Up for Kalshi: Step-by-Step Walkthrough for US Users (2026)

Step-by-step 2026 walkthrough for US users signing up to Kalshi — eligibility check, account creation, KYC with SSN, ACH funding from your bank, finding...

lol model analysis

Why Our League of Legends Model Found 21 Edges This Week

League of Legends prediction model results: 8W-13L, 38.1% win rate. ML-powered fair value vs Polymarket prices.

soccer model analysis

Why Our SOCCER Model Found 21 Edges This Week

SOCCER prediction model results: 8W-13L, 38.1% win rate. ML-powered fair value vs Polymarket prices.

polymarket backtesting datasets

Backtesting Polymarket Strategies: Tools, Datasets, and the Depth Data Problem

Practical guide to backtesting Polymarket trading strategies in 2026 — the free CLOB price-history API, what it misses (orderbook depth), how to model...

polymarket bot python

How to Build a Polymarket Bot in Python: Architecture, Components, and What Actually Matters

Practical architecture guide for building a Polymarket trading bot in Python in 2026 — the eight components you need, how they fit together, what to build...

kalshi polymarket prediction-markets

Kalshi Alternatives in 2026: Honest Comparison of the Real Options

Practical 2026 comparison of Kalshi alternatives — Polymarket, PredictIt, Manifold, Robinhood Event Contracts, and sportsbook futures. Liquidity, fees...

polymarket api documentation

Polymarket API Documentation: A Practical Guide to What the Docs Don't Tell You

Practical orientation to Polymarket's API documentation in 2026 — the three API surfaces, what the official docs cover well, the operational gotchas...

polymarket paper-trading backtesting

Polymarket Paper Trading: How to Test Strategies Without Risking Money in 2026

Polymarket has no built-in paper trading mode. Here are the real options for testing strategies without risk — Manifold Markets, historical price...

kalshi parlay combo-orders

Can You Parlay on Kalshi? Combo Orders and Multi-Leg Bets Explained in 2026

Direct answer to whether Kalshi supports parlays in 2026 — what Kalshi's actual order types do, the structural reason event contract exchanges don't offer...

polymarket beginner tutorial

How to Bet on Polymarket: Step-by-Step for First-Time Users in 2026

Practical 2026 walkthrough for first-time Polymarket users — geographic access, wallet setup, USDC funding on Polygon, finding sports markets, placing...

polymarket kalshi prediction-markets

Polymarket vs Kalshi: Which Sports Prediction Market Is Better in 2026?

Head-to-head comparison of Polymarket and Kalshi for sports prediction trading in 2026 — liquidity per sport, fees, regulation, API access, and which...

kalshi nfl mvp

Kalshi NFL MVP Market: How to Read Live Odds, Volume, and Find Edge in 2026

Structural guide to the Kalshi NFL MVP market — how multi-outcome contracts work, how to read per-player implied probabilities, seasonal liquidity...

polymarket fees clob

Polymarket Fees Explained: Maker, Taker, and the CLOB Fee Schedule in 2026

Practical guide to how Polymarket fees actually work in 2026 — maker vs taker, per-market variation, the NCAAMB winnings fee, gas costs on Polygon, and...

comparison tools api

Top Sports Prediction Tools in 2026 (Honest Comparison)

Comparison of the most useful sports prediction tools in 2026 — calibrated APIs, odds aggregators, public model dashboards, live data feeds, and bot...

results polymarket trading-bots

Polymarket Trading Bots in the Wild: A Full Breakdown of Our On-Chain P&L by Market Type

Honest breakdown of our automated Polymarket trading bots' on-chain P&L by market type — moneyline vs spread vs total, in-play vs pregame, sport by sport...

api prediction-markets calibration

What Is a Sports Prediction API? A 2026 Practical Explainer

Plain-English guide to sports prediction APIs in 2026 — what they return, how authentication and rate limits work, what calibration means, and how to...

api tutorial python

How to Leverage a Sports Prediction API: A Step-by-Step Developer Guide

Pragmatic seven-step workflow for integrating a sports prediction API into your trading bot, dashboard, or research pipeline — auth, polling cadence, edge...

architecture python websocket

How to Build a Real-Time Edge Signals Scanner for Sports Markets

Architecture and Python patterns for scanning live sports markets in real time and surfacing edge signals — WebSocket subscriptions, latency budgets, edge...

polymarket calibration validation

Comparing Polymarket Odds to ZenHodl Win Probabilities Across 5,000 Games

Head-to-head comparison of ZenHodl's calibrated win probabilities against Polymarket's market-implied probabilities across 5,000+ resolved games. Where...

strategy machine-learning kelly-criterion

Betting Strategies With Calibrated ML Probabilities (Without Going Broke)

A practical playbook for turning calibrated machine-learning win probabilities into profitable bets — fair-value gates, Kelly sizing, edge band filters...

research market-efficiency polymarket

What Our On-Chain Results Say About Market Efficiency in Sports Prediction Markets

A year of on-chain trading data on Polymarket — what it reveals about sports prediction market efficiency, where systematic mispricing persists, and where...

odds conversion math

Betting Odds Converter Guide: American, Decimal, Fractional, and Implied Probability

Complete guide to betting odds formats with conversion math — American, decimal, fractional, and implied probability — plus how vig distorts the implied...

api schema design

11 Sports, One API: Designing a Unified Schema for Multi-Sport Win Probabilities

How we designed a single unified API schema that serves calibrated win probabilities for 11 different sports — basketball, hockey, baseball, football...

position-sizing kelly-criterion drawdown

Drawdown-Aware Position Sizing: When Kelly Tells You To Bet Less

Full Kelly assumes your edge is real. After six losing days in a row, that assumption deserves a second look. How we layered a drawdown-aware sizing ramp...

kelly-criterion prediction-markets position-sizing

Kelly Criterion for Prediction Markets: How to Size Your Bets Without Going Broke

The Kelly Criterion tells you the mathematically optimal bet size when you have an edge. Most traders bet 2-4x too much. Here's the formula, the Python...

sports-prediction-api python fastapi

How to Build a Sports Prediction API with Python in 2026

Step-by-step guide to building a sports prediction API in Python, from live data collection and feature engineering to model calibration and FastAPI...

benchmark calibration nba

Why We Can't Retroactively Benchmark NBA First Round 2026 — And Why That's The Point

Several people asked why the pre-committed NBA Playoffs benchmark starts at Conference Semifinals instead of covering First Round games already in...

benchmark calibration nba

We Just Pre-Committed to Beating Polymarket on NBA Playoffs Calibration. The Hash Is On-Chain.

We just announced and on-chain anchored a 7-week head-to-head benchmark: ZenHodl's NBA model vs the live Polymarket consensus, every Conference Semis...

calibration ece transparency

We Audited 21 Sports Prediction Sources. Only 1 Publishes Their Calibration Error.

We surveyed 21 sports prediction providers — KenPom, BetQL, Sportradar, FiveThirtyEight, MoneyPuck, OddsJam, and 15 others — for the one number a...

nhl stanley-cup playoffs

We Backtested Our NHL Model on the 2025 Stanley Cup Playoffs. It Hit 60.5% Across 86 Games.

After Florida beat Edmonton 4-2 to repeat as Stanley Cup champions in 2025, we ran our NHL win-probability model on every playoff game using only...

champions-league ucl soccer

UCL 2025-26 Champions League: We're Down to 4 Teams. Here's Who Our Model Says Wins.

PSG, Arsenal, Atlético Madrid, and Bayern Munich are the 2025-26 UCL semifinalists. Our production club-soccer model (trained on 3,000+ matches, 75%...

sportsbook-bonuses promos math

Sportsbook Welcome Bonuses 2026: The Real Math Behind 'Free Bets' (And the 3 That Are Actually Worth It)

A math-first 2026 analysis of sportsbook welcome bonuses, bonus bets, and promo codes. Most 'free $200' offers are net-negative in expected value once you...

prediction-markets sports beginners

How Prediction Markets Work for Sports: A 2026 Beginner's Guide

Prediction markets are the fastest-growing alternative to traditional sportsbooks. This 2026 guide explains what they are, how they differ from...

ai-sports-predictions machine-learning calibration

Free AI Sports Predictions 2026: How to Tell Real ML From ChatGPT-in-a-Trench-Coat

A 2026 honest guide to AI sports predictions. Most 'AI' picks sites are ChatGPT wrappers generating narrative content around sportsbook lines. The genuine...

calibration probability prediction-markets

Why Your 70% Confidence Should Actually Mean 70%: Calibrated Probabilities in Prediction Markets

Most sports prediction models are accurate but not calibrated — and that gap is why their backtests lie. A practical guide to what calibration means, how...

football nfl ncaaf

What Is the Best Accurate Platform for Football Predictions? A Buyer's Guide From Someone Who Ships One

Most sports prediction platforms advertise accuracy that doesn't hold up to measurement. Here's how to evaluate one properly — with published ECE...

mlb world-series baseball

We Backtested Our MLB Model on the 2025 Postseason. It Hit 59.6% Across 47 Games.

After the 2025 World Series ended in November, we ran our MLB win-probability model on every postseason game — Wild Card through Game 7 — using only...

sports-prediction-apps accuracy calibration

Are Sports Prediction Apps Accurate, or Just Hype? (2026 Honest Answer)

A 2026 honest answer to whether sports prediction apps actually work. Most 'expert picks' sites are post-hoc curation of sportsbook lines; about 5%...

prediction-markets insider-trading polymarket

Are Insiders Really Exploiting Prediction Markets? What the Data Actually Shows

A 2026 investigation of insider trading in prediction markets. We examine the 2024 Polymarket election dispute, academic studies of PredictIt...

sports-betting long-term kelly-criterion

Can You Actually Win at Sports Betting Long Term? (What the Math Says in 2026)

An honest, math-first answer to whether you can profit from sports betting long-term. The arithmetic of edge, vig, variance, and Kelly sizing — plus the 5...

nhl stanley-cup playoffs

2026 Stanley Cup Odds: Every Team's Championship Probability (Live, April 22)

Two days into the 2026 NHL playoffs. Our calibrated NHL model has Colorado and Tampa Bay as the Cup favorites, with Carolina close behind. Here's every...

entertainment-purposes-only sports-picks disclaimers

The 'Entertainment Purposes Only' Disclaimer: What It Actually Reveals About a Picks Site

Every major sports picks site says 'for entertainment purposes only' — but what does that actually mean? It's a legal admission that the publisher doesn't...

super-bowl nfl playoffs

We Backtested Our NFL Model on the 2026 Playoffs. It Called Super Bowl LX Correctly.

After Super Bowl LX wrapped on February 8, we ran our NFL win-probability model on every 2025-26 playoff game using only pre-playoff data. It hit 9 of 13...

world-cup fifa soccer

2026 FIFA World Cup Odds: Every Team's Championship Probability (April 2026)

The 2026 FIFA World Cup kicks off June 11 in USA/Canada/Mexico. Our Monte Carlo bracket simulator gives Argentina a 26.2% chance to repeat, Brazil at...

nba nba-finals basketball

We Backtested Our NBA Model on the 2025 Playoffs. It Called OKC Correctly All Season.

After the 2025 NBA Finals wrapped with OKC beating Indiana in seven games, we ran our NBA win-probability model on all 84 postseason games using only...

college-football ncaaf calibration

Why Our First CFB Model Lost Money (And the One Feature That Fixed It)

Our initial college football win probability model backtested at -2.1c/trade across 728 simulated positions. The bug wasn't the model — it was a feature...

ncaamb college-basketball season-report

Our NCAAMB Model's 2025-26 Season Report: 5,345 Games Backtested, 68.2% Accuracy, ECE 4.39%

We backtested our NCAAMB win-probability model on every non-tournament game of the 2025-26 college basketball season — 5,345 games. Accuracy: 68.19%...

march-madness ncaamb backtest

We Backtested Our Model on the 2026 March Madness Bracket. It Hit 71.6%.

After the 2026 NCAA tournament ended, we ran our NCAAMB win-probability model on all 67 games using only pre-tournament data. It called 48 of 67 correctly...

prediction-markets kalshi polymarket

Best Prediction Market Apps 2026: Kalshi vs Polymarket vs PredictIt vs Manifold

A developer and trader's guide to the best prediction market platforms in 2026. Kalshi, Polymarket, PredictIt, Manifold Markets, and ForecastEx — compared...

research prediction-markets polymarket

The State of Prediction Markets in 2026: Data, Liquidity, and What Actually Works

Original research on prediction market liquidity, accuracy, and profitability across Polymarket, Kalshi, DraftKings, and FanDuel. Based on 25M+ data...

api polymarket kalshi

The Complete Guide to Prediction Market APIs (Polymarket, Kalshi, and Sportsbooks)

Every prediction market API compared: Polymarket CLOB, Kalshi REST, DraftKings odds via The Odds API. Authentication, endpoints, rate limits, and Python...

model win-probability tutorial

Win Probability Models for Sports Betting: The Math, The Code, and The Mistakes

How win probability models actually work — from Elo ratings through logistic regression to XGBoost. Includes calibration, feature engineering, and the...

lol model analysis

Why Our League of Legends Model Found 23 Edges This Week

League of Legends prediction model results: 10W-13L, 43.5% win rate. ML-powered fair value vs Polymarket prices.

results weekly trading

Week 16 Results: 118W-83L, +$14.97

ZenHodl week 16 live trading results across 7 sports. 58.7% win rate on 201 trades.

atp model analysis

Why Our ATP Model Found 17 Edges This Week

ATP prediction model results: 9W-8L, 52.9% win rate. ML-powered fair value vs Polymarket prices.

nhl model analysis

Why Our NHL Hockey Model Found 40 Edges This Week

NHL Hockey prediction model results: 28W-12L, 70.0% win rate. ML-powered fair value vs Polymarket prices.

nba model analysis

Why Our NBA Basketball Model Found 12 Edges This Week

NBA Basketball prediction model results: 6W-6L, 50.0% win rate. ML-powered fair value vs Polymarket prices.

polymarket trading results

Our Polymarket Trading Results: 335 Live Trades Across 10 Sports

Transparent breakdown of 335 live Polymarket trades across NBA, MLB, NHL, tennis, LoL, CS2, and more. Win rates, P&L by sport, what worked and what didn't.

soccer model analysis

Why Our SOCCER Model Found 8 Edges This Week

SOCCER prediction model results: 3W-5L, 37.5% win rate. ML-powered fair value vs Polymarket prices.

cs2 model analysis

Why Our Counter-Strike 2 Model Found 29 Edges This Week

Counter-Strike 2 prediction model results: 11W-18L, 37.9% win rate. ML-powered fair value vs Polymarket prices.

nba machine-learning behind-the-scenes

How We Predict NBA Games with Machine Learning

Inside ZenHodl's NBA prediction engine: XGBoost models, team stats, real-time injury overlays, and isotonic calibration. How our ML system processes...

mlb model analysis

Why Our MLB Baseball Model Found 72 Edges This Week

MLB Baseball prediction model results: 51W-21L, 70.8% win rate. ML-powered fair value vs Polymarket prices.

nba python machine-learning

Build an NBA Win Probability Model in Python: From Box Scores to Live Predictions

Complete tutorial for building an NBA live win probability model in Python using XGBoost. Covers data collection, feature engineering, training...

api comparison odds

Sports Odds API Comparison 2026: The Odds API vs ZenHodl vs Building Your Own

Comparing the top sports data APIs for prediction modeling and trading in 2026. Coverage, pricing, latency, and what each is best for.

polymarket trading strategy

How We Made $2,400 on Polymarket: Verified On-Chain Results and the Strategy Behind Them

We run automated prediction bots on Polymarket across 7 sports. Here's our verified P&L, the strategy, and what we learned from 938+ live trades.

multi-venue polymarket sportsbooks

Multi-Venue Edge Detection: How Polymarket Disagrees With DraftKings

The same NBA game is priced differently on Polymarket, DraftKings, FanDuel, and BetMGM. Here's the math, the architecture, and the actual disagreements we...

strategy discipline polymarket

Why We Reject 65% of Our Own Trading Signals

Our system finds dozens of trading signals per day. We trade 35% of them. The discipline to reject bad signals is worth more than the ability to find good...

calibration ml debugging

Calibration Beats Accuracy: The NBA Model Bug That Lost Money at 65% Win Rate

Our NBA bot had 65% accuracy and was losing money. The problem wasn't the model — it was a calibration bug that left it confidently wrong. Here's how we...

cs2 esports polymarket

Building a CS2 Betting Bot: Round Economy, Map Pools, and the Data Problem

Counter-Strike 2 has the widest mispricings on Polymarket. It also has the worst data infrastructure. Here's how we built a 4-tier model that handles both.

transparency debugging polymarket

How We Improved 5 Trading Bots in One Week

We audited every bot, found the gaps between backtest and live performance, and fixed them. CS2, NBA, MLB, LoL, and Tennis — five different problems, five...

infrastructure vps deployment

Running a Profitable Trading Bot for $13 a Month

You don't need a quant fund. Our complete trading infrastructure runs on a $7/month VPS plus $5/month for sportsbook odds. Here's the full breakdown.

lol model analysis

Why Our League of Legends Model Found 16 Edges This Week

League of Legends prediction model results: 10W-6L, 62.5% win rate. ML-powered fair value vs Polymarket prices.

cs2 model analysis

Why Our Counter-Strike 2 Model Found 44 Edges This Week

Counter-Strike 2 prediction model results: 19W-25L, 43.2% win rate. ML-powered fair value vs Polymarket prices.

ncaawb model analysis

Why Our NCAAWB Model Found 3 Edges This Week

NCAAWB prediction model results: 3W-0L, 100.0% win rate. ML-powered fair value vs Polymarket prices.

nba model analysis

Why Our NBA Basketball Model Found 6 Edges This Week

NBA Basketball prediction model results: 2W-4L, 33.3% win rate. ML-powered fair value vs Polymarket prices.

mlb model analysis

Why Our MLB Baseball Model Found 33 Edges This Week

MLB Baseball prediction model results: 21W-12L, 63.6% win rate. ML-powered fair value vs Polymarket prices.

results weekly trading

Week 15 Results: 85W-62L, +$69.01

ZenHodl week 15 live trading results across 9 sports. 57.8% win rate on 147 trades.

nhl model analysis

Why Our NHL Hockey Model Found 26 Edges This Week

NHL Hockey prediction model results: 16W-10L, 61.5% win rate. ML-powered fair value vs Polymarket prices.

soccer model analysis

Why Our SOCCER Model Found 3 Edges This Week

SOCCER prediction model results: 2W-1L, 66.7% win rate. ML-powered fair value vs Polymarket prices.

ncaamb model analysis

Why Our College Basketball Model Found 4 Edges This Week

College Basketball prediction model results: 4W-0L, 100.0% win rate. ML-powered fair value vs Polymarket prices.

atp model analysis

Why Our ATP Model Found 12 Edges This Week

ATP prediction model results: 8W-4L, 66.7% win rate. ML-powered fair value vs Polymarket prices.

strategy polymarket settlement

Hold to Settlement: Why We Never Sell Our Prediction Market Positions

Every one of our bots holds to settlement instead of actively trading. Here's why patience crushes activity on Polymarket — and the failed strategies that...

multi-venue edges polymarket

How to Find Mispriced Lines Across Polymarket, DraftKings, and FanDuel

The same game is priced differently on Polymarket, DraftKings, FanDuel, and BetMGM. Here's how to systematically find and exploit the differences.

results transparency polymarket

We Run 5 Bots Across 8 Sports — Here's What's Actually Profitable

Real P&L from 5 live Polymarket bots trading NBA, MLB, NHL, NCAAMB, CS2, LoL, Tennis, and Soccer. Honest about what works and what doesn't.

tennis model analysis

Why Our Tennis Model Found 6 Edges This Week

Tennis prediction model results: 6W-0L, 100.0% win rate. ML-powered fair value vs Polymarket prices.

polymarket python api

Polymarket API Python Tutorial: Connect, Fetch Orderbooks, and Place Trades

Step-by-step guide to using the Polymarket CLOB API in Python. Covers authentication, reading orderbooks, fetching market data, and placing limit orders...

results weekly trading

Week 14 Results: 9W-2L, -$0.91

ZenHodl week 14 live trading results across 5 sports. 81.8% win rate on 11 trades.

execution microstructure backtest

99% of Your Backtested Edge Doesn't Exist: Execution Quality on Prediction Markets

We backtested 237 trade signals with and without execution constraints. 99% of theoretical profit vanished. Here's what actually kills your trades — and...

strategy model feature engineering

Why Simple Models Beat Complex Ones in Sports Betting

A 6-feature model outperforms a 50-feature model at making money — even with a worse accuracy score. Here's why, and what it means for how you should...

calibration model python

Sports Betting Model Calibration: Why It Matters More Than Accuracy

A well-calibrated model makes money even with lower accuracy. Learn how to measure calibration with Brier score and ECE, and fix it with isotonic...

websocket python data

Stream Live Sports Data with WebSockets in Python

How to get real-time sports scores using WebSockets in Python. Compares HTTP polling vs WebSocket streaming, with working code for building a live data feed.

elo python tutorial

Build an Elo Rating System from Scratch in Python

A complete step-by-step tutorial to implement an Elo rating system in Python for sports prediction. Covers the math, K-factor tuning, season resets, and...

backtest python strategy

How to Backtest a Sports Betting Strategy in Python (Without Fooling Yourself)

A practical guide to backtesting sports betting and prediction market strategies in Python. Covers the common pitfalls — survivorship bias, look-ahead...

espn python scraping

ESPN API with Python: Scrape 60,000+ Games for Sports Analytics

How to use Python to scrape live scores, play-by-play data, and win probabilities from ESPN's hidden API. Complete tutorial with working code.

sports betting bot beginner

How Prediction Market Bots Work (And How to Build One)

A beginner's guide to automated trading on Polymarket. Learn how bots find edges using win probability models, and how to build your own.

elo python model

Elo Ratings for Sports Betting: A Complete Python Guide

How to implement Elo ratings from scratch in Python for sports prediction. Covers home advantage, K-factor tuning, and season resets.