// GUIDE — WINDOWS

Kalshi CLI Setup on Windows

May 21, 2026 · Yeti Games, LLC · 8 min read

The Windows setup follows the same logic as macOS but uses PowerShell instead of Terminal, has different file paths, and requires a few extra steps for OpenSSL. This guide covers the full setup plus the three errors that catch most people: InvalidByte, NOT_FOUND, and the missing positions bug.

1. Prerequisites

Install these first if you don't have them:

• Python 3.9+ — python.org/downloads — check "Add Python to PATH" during install
• Git — git-scm.com/download/win
• Node.js 18+ — nodejs.org (for Claude Code)

Verify in PowerShell:

python --version
git --version
node --version

2. Credential Setup

Create a directory for your keys:

mkdir $HOME.kalshi

Set environment variables permanently via PowerShell:

[System.Environment]::SetEnvironmentVariable("KALSHI_ACCESS_KEY", "your-uuid-here", "User")
[System.Environment]::SetEnvironmentVariable("KALSHI_PRIVATE_KEY_PATH", "$HOME.kalshiprivate_key.pem", "User")
[System.Environment]::SetEnvironmentVariable("KALSHI_ENVIRONMENT", "demo", "User")

Close and reopen PowerShell after setting these. Verify:

echo $env:KALSHI_ACCESS_KEY

3. Fixing the InvalidByte Error

Same cause as macOS: copying your private key from a browser corrupts the PEM file with hidden characters or smart quotes. The CLI throws:

ValueError: InvalidData(InvalidByte(4, 95))

Install OpenSSL for Windows from slproweb.com (grab the Win64 installer, not Light). Then in PowerShell:

openssl pkcs8 -topk8 -inform PEM -outform PEM -nocrypt `
  -in $HOME.kalshiprivate_key.pem `
  -out $HOME.kalshiprivate_key_fixed.pem

Move-Item $HOME.kalshiprivate_key_fixed.pem $HOME.kalshiprivate_key.pem -Force

4. Fixing the NOT_FOUND Error (Demo Mode)

If you're using demo credentials and every request returns NOT_FOUND, the CLI is hitting the production server instead of demo.

Find cli.py — typically at:

C:UsersYourNameAppDataLocalProgramsPythonPython3xxLibsite-packageskalshi_clicli.py

Or locate it with:

python -c "import kalshi_cli; print(kalshi_cli.__file__)"

Open in Notepad or VS Code and add the environment switch:

import os

KALSHI_ENV = os.getenv("KALSHI_ENVIRONMENT", "prod").lower()

if KALSHI_ENV == "demo":
    BASE_URL = "https://external-api.demo.kalshi.co"
else:
    BASE_URL = "https://api.elections.kalshi.com"

Add PowerShell functions to your $PROFILE for easy switching:

# Open profile:
notepad $PROFILE

# Add these lines:
function kalshi-demo { $env:KALSHI_ENVIRONMENT = "demo"; Write-Host "→ DEMO" }
function kalshi-prod { $env:KALSHI_ENVIRONMENT = "prod"; Write-Host "→ PRODUCTION" }

5. Fixing the Missing Positions Bug

Symptom: kalshi positionsshows "No open positions" even with open trades.

Cause: Kalshi changed their API — the integer position field was replaced by a string field position_fp. The CLI filters on the old field, so all positions read as zero and get dropped.

In the same cli.py from Section 4, find and replace the position-loading block:

# Before (original two lines):
ps = data.get("market_positions", [])
ps = [p for p in ps if p.get("position", 0) != 0]

# After (replace with this block):
ps = data.get("market_positions", [])
for p in ps:
    if p.get("position", 0) == 0 and p.get("position_fp"):
        try:
            p["position"] = int(float(p["position_fp"]))
        except (ValueError, TypeError):
            pass
ps = [p for p in ps if p.get("position", 0) != 0]

No restart needed. Run kalshi positions to verify your open positions now appear.

6. Troubleshooting Checklist

Next Steps

CLI running? The next step is the 5-step AI trading workflow. The Claude Kalshi Playbook ($17) covers scanning for opportunities, stress-testing research with an adversarial AI pass, and executing trades with smart order placement.