pal-e-docs

API Integration: prediction-assistant

arch-api Architecture

architecture
Project

API Integration

Kalshi REST API integration layer. Answers: how does the app communicate with the Kalshi exchange?

Diagram




          
  
Components



          
  

    

        
          

              Component
              Purpose
              Notes
          

        
      
          

              RSA-PSS Signer
              Signs each API request with user's private key
              RSA-PSS SHA-256. Signs {timestamp_ms}{HTTP_METHOD}{path}
          

          

              Kalshi REST API
              Exchange API for markets, orders, portfolio
              Base: https://external-api.kalshi.com/trade-api/v2
          

          

              Kalshi WebSocket
              Real-time market data streaming
              wss://api.kalshi.com/trade-api/ws/v2
          

          

              Demo API
              Sandbox environment for development
              https://external-api.demo.kalshi.co/trade-api/v2
          

      
    

  



          
  
Key Decisions



          
  
    
      
  • RSA-PSS over session tokens — Kalshi requires per-request RSA-PSS SHA-256 signing. No OAuth, no session cookies. Each request carries three headers: KALSHI-ACCESS-KEY, KALSHI-ACCESS-TIMESTAMP, KALSHI-ACCESS-SIGNATURE.
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  • Basic tier rate limits constrain scanning — 20 reads/sec and 10 writes/sec at Basic tier. Watchdog strategy (scanning all live markets) must stay within these bounds. Poll only same-day markets, batch where possible.
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  • Demo-first development — All development and testing against demo.kalshi.co. Production keys used only in deployed app with real user accounts.
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  • No fund handling — The app never touches deposits or withdrawals. All money flows through Kalshi directly. We only read balances and execute trades via API.
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  • WebSocket for live monitoring — REST polling is sufficient for market scanning at Basic tier, but WebSocket provides real-time updates for active position monitoring without burning read quota.
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Rate Limits



          
  

    

        
          

              Tier
              Read/sec
              Write/sec
          

        
      
          

              Basic
              20
              10
          

          

              Advanced
              30
              30
          

          

              Premier
              100
              100
          

          

              Prime
              400
              400
          

      
    

  



          
  
Key Endpoint Groups



          
  

    

        
          

              Group
              Key Endpoints
              Usage
          

        
      
          

              Markets
              GET /markets, GET /markets/{ticker}/orderbook
              Market scanning, orderbook analysis
          

          

              Orders
              POST /portfolio/orders, DELETE /portfolio/orders/{id}
              Trade execution and cancellation
          

          

              Portfolio
              GET /portfolio/positions, GET /portfolio/balance
              Position tracking, balance checks
          

          

              Events
              GET /events, GET /events/{ticker}
              Event metadata, fee schedules