PropLine is an API that provides real-time betting odds for player props across 54 sports and 25 books, including prominent ones like Pinnacle and six exchanges (Kalshi, Polymarket, Smarkets, Matchbook, Novig, ProphetX), which are not available on platforms like the-odds-api and OddsJam. Distinguishing itself from others, it uniquely resolves player props based on actual box scores, delivering outcomes for every Over/Under bet, indicating whether it was won, lost, pushed, or voided, along with the actual statistical values. The pricing model charges per request rather than per credit, meaning that player prop bets and alternative lines won't inflate your expenses as they often do with credit-based APIs. Additionally, the response format is compatible with the-odds-api, making the transition to using it as simple as changing the base URL. Users can access a free tier that allows for 1,000 requests per day without requiring a credit card. The Hobby plan, at $9 per month, covers 5,000 requests daily and unlocks every paid feature: cross-book +EV with no-vig fair lines, historical line movement, opening and closing lines for CLV tracking, and graded prop resolution. The Pro plan, at $19 per month, raises that to 25,000 requests daily and adds bulk CSV exports. Streaming Lite at $39 per month provides 100,000 requests daily and Streaming at $79 per month provides 1 million, both with HMAC-signed webhooks that push line movements and settled results as they happen. PropLine also offers official SDKs for Python, Node, MCP, and CLI, ensuring users have a seamless integration experience.