Pulsify | Playground - Try the code editor

{
  "context": {
    "listing": {
      "asin": "B00EXAMPLE01",
      "condition": "used",
      "subcondition": "good",
      "price": 15.27,
      "floor": 10.0,
      "ceiling": 25.0,
      "shipping": 0.0,
      "b2bPrice": null,
      "fulfillmentChannel": "Amazon",
      "quantity": 3,
      "enabled": true,
      "suppressed": false
    }
  },
  "event": {
    "NotificationVersion": "1.0",
    "NotificationType": "ANY_OFFER_CHANGED",
    "PayloadVersion": "1.0",
    "EventTime": "2024-11-18T14:31:09.305Z",
    "NotificationMetadata": {
      "ApplicationId": "amzn1.sellerapps.app.00000000-0000-0000-0000-000000000000",
      "SubscriptionId": "00000000-0000-0000-0000-000000000000",
      "PublishTime": "2024-11-18T14:31:09.453Z",
      "NotificationId": "00000000-0000-0000-0000-000000000000"
    },
    "Payload": {
      "AnyOfferChangedNotification": {
        "SellerId": "A1EXAMPLE00001",
        "OfferChangeTrigger": {
          "MarketplaceId": "ATVPDKIKX0DER",
          "ASIN": "B00EXAMPLE01",
          "ItemCondition": "used",
          "TimeOfOfferChange": "2024-11-18T14:31:09.116Z",
          "OfferChangeType": "Internal"
        },
        "Summary": {
          "NumberOfOffers": [
            {
              "Condition": "used",
              "FulfillmentChannel": "Merchant",
              "OfferCount": 7
            },
            {
              "Condition": "new",
              "FulfillmentChannel": "Amazon",
              "OfferCount": 7
            },
            {
              "Condition": "used",
              "FulfillmentChannel": "Amazon",
              "OfferCount": 7
            },
            {
              "Condition": "new",
              "FulfillmentChannel": "Merchant",
              "OfferCount": 5
            }
          ],
          "LowestPrices": [
            {
              "Condition": "used",
              "FulfillmentChannel": "Merchant",
              "LandedPrice": {
                "Amount": 13.95,
                "CurrencyCode": "USD"
              },
              "ListingPrice": {
                "Amount": 9.96,
                "CurrencyCode": "USD"
              },
              "Shipping": {
                "Amount": 3.99,
                "CurrencyCode": "USD"
              }
            },
            {
              "Condition": "new",
              "FulfillmentChannel": "Amazon",
              "LandedPrice": {
                "Amount": 42.42,
                "CurrencyCode": "USD"
              },
              "ListingPrice": {
                "Amount": 42.42,
                "CurrencyCode": "USD"
              },
              "Shipping": {
                "Amount": 0.0,
                "CurrencyCode": "USD"
              }
            },
            {
              "Condition": "used",
              "FulfillmentChannel": "Amazon",
              "LandedPrice": {
                "Amount": 15.27,
                "CurrencyCode": "USD"
              },
              "ListingPrice": {
                "Amount": 15.27,
                "CurrencyCode": "USD"
              },
              "Shipping": {
                "Amount": 0.0,
                "CurrencyCode": "USD"
              }
            },
            {
              "Condition": "new",
              "FulfillmentChannel": "Merchant",
              "LandedPrice": {
                "Amount": 41.15,
                "CurrencyCode": "USD"
              },
              "ListingPrice": {
                "Amount": 41.15,
                "CurrencyCode": "USD"
              },
              "Shipping": {
                "Amount": 0.0,
                "CurrencyCode": "USD"
              }
            }
          ],
          "BuyBoxPrices": [
            {
              "Condition": "New",
              "LandedPrice": {
                "Amount": 42.42,
                "CurrencyCode": "USD"
              },
              "ListingPrice": {
                "Amount": 42.42,
                "CurrencyCode": "USD"
              },
              "Shipping": {
                "Amount": 0.0,
                "CurrencyCode": "USD"
              }
            },
            {
              "Condition": "Used",
              "LandedPrice": {
                "Amount": 15.27,
                "CurrencyCode": "USD"
              },
              "ListingPrice": {
                "Amount": 15.27,
                "CurrencyCode": "USD"
              },
              "Shipping": {
                "Amount": 0.0,
                "CurrencyCode": "USD"
              }
            }
          ],
          "ListPrice": {
            "Amount": 59.99,
            "CurrencyCode": "USD"
          },
          "SalesRankings": [
            {
              "ProductCategoryId": "example_category",
              "Rank": 69143
            },
            {
              "ProductCategoryId": "1234567890",
              "Rank": 21635
            }
          ],
          "NumberOfBuyBoxEligibleOffers": [
            {
              "Condition": "used",
              "FulfillmentChannel": "Merchant",
              "OfferCount": 7
            },
            {
              "Condition": "new",
              "FulfillmentChannel": "Amazon",
              "OfferCount": 7
            },
            {
              "Condition": "used",
              "FulfillmentChannel": "Amazon",
              "OfferCount": 7
            },
            {
              "Condition": "new",
              "FulfillmentChannel": "Merchant",
              "OfferCount": 4
            }
          ]
        },
        "Offers": [
          {
            "SellerId": "A1EXAMPLE00001",
            "SubCondition": "good",
            "SellerFeedbackRating": {
              "FeedbackCount": 1250,
              "SellerPositiveFeedbackRating": 98
            },
            "ShippingTime": {
              "MinimumHours": 0,
              "MaximumHours": 0,
              "AvailabilityType": "NOW",
              "AvailableDate": ""
            },
            "ListingPrice": {
              "Amount": 15.27,
              "CurrencyCode": "USD"
            },
            "Shipping": {
              "Amount": 0.0,
              "CurrencyCode": "USD"
            },
            "IsFulfilledByAmazon": true,
            "IsBuyBoxWinner": true,
            "PrimeInformation": {
              "IsOfferPrime": true,
              "IsOfferNationalPrime": true
            },
            "IsFeaturedMerchant": true,
            "ShipsDomestically": true
          },
          {
            "SellerId": "A1EXAMPLE00002",
            "SubCondition": "very_good",
            "SellerFeedbackRating": {
              "FeedbackCount": 81877,
              "SellerPositiveFeedbackRating": 96
            },
            "ShippingTime": {
              "MinimumHours": 24,
              "MaximumHours": 48,
              "AvailabilityType": "NOW",
              "AvailableDate": ""
            },
            "ListingPrice": {
              "Amount": 9.96,
              "CurrencyCode": "USD"
            },
            "Shipping": {
              "Amount": 3.99,
              "CurrencyCode": "USD"
            },
            "ShipsFrom": {
              "Country": "US",
              "State": "TX"
            },
            "IsFulfilledByAmazon": false,
            "IsBuyBoxWinner": false,
            "PrimeInformation": {
              "IsOfferPrime": false,
              "IsOfferNationalPrime": false
            },
            "IsFeaturedMerchant": true,
            "ShipsDomestically": true
          },
          {
            "SellerId": "A1EXAMPLE00003",
            "SubCondition": "good",
            "SellerFeedbackRating": {
              "FeedbackCount": 739,
              "SellerPositiveFeedbackRating": 96
            },
            "ShippingTime": {
              "MinimumHours": 0,
              "MaximumHours": 0,
              "AvailabilityType": "NOW",
              "AvailableDate": ""
            },
            "ListingPrice": {
              "Amount": 15.49,
              "CurrencyCode": "USD"
            },
            "Shipping": {
              "Amount": 0.0,
              "CurrencyCode": "USD"
            },
            "IsFulfilledByAmazon": true,
            "IsBuyBoxWinner": false,
            "PrimeInformation": {
              "IsOfferPrime": true,
              "IsOfferNationalPrime": true
            },
            "IsFeaturedMerchant": true,
            "ShipsDomestically": true
          },
          {
            "SellerId": "A1EXAMPLE00004",
            "SubCondition": "good",
            "SellerFeedbackRating": {
              "FeedbackCount": 11,
              "SellerPositiveFeedbackRating": 91
            },
            "ShippingTime": {
              "MinimumHours": 0,
              "MaximumHours": 0,
              "AvailabilityType": "FUTURE_WITH_DATE",
              "AvailableDate": "2024-11-21T12:00:00.000Z"
            },
            "ListingPrice": {
              "Amount": 16.25,
              "CurrencyCode": "USD"
            },
            "Shipping": {
              "Amount": 0.0,
              "CurrencyCode": "USD"
            },
            "IsFulfilledByAmazon": true,
            "IsBuyBoxWinner": false,
            "PrimeInformation": {
              "IsOfferPrime": true,
              "IsOfferNationalPrime": true
            },
            "IsFeaturedMerchant": true,
            "ShipsDomestically": true
          }
        ]
      }
    }
  }
}

const CONVERGENCE_THRESHOLD = 0.01; // 1% - stop optimizing when boundaries this close

function handle(event, context) {
  const listing = context.listing;
  const notification = event.Payload?.AnyOfferChangedNotification;
  const summary = notification?.Summary;
  const sellerId = notification?.SellerId;

if (!listing.floor || !listing.ceiling) return context;

// Find my offer and the winning competitor
  const offers = notification?.Offers || [];
  const myOffer = offers.find((o) => o.SellerId === sellerId);

// Can't act without our own offer in the notification
  if (!myOffer) return context;

// Only learn when we're featured (Buy Box eligible)
  if (!myOffer.IsFeaturedMerchant) {
    return context;
  }

const shipping = myOffer.Shipping?.Amount ?? listing.shipping;
  const winningCompetitor = offers.find(
    (o) => o.SellerId !== sellerId && o.IsBuyBoxWinner,
  );

// Buy box suppressed - no winner exists
  if (!winningCompetitor && !myOffer.IsBuyBoxWinner) {
    // Explore toward floor to try becoming buy-box eligible
    const myLanded = landedPrice(myOffer);
    const midpoint = (listing.floor + (myLanded - shipping)) / 2;
    listing.set({ price: round(midpoint) });
    return context;
  }

// Note: Bisection toward floor converges naturally - no state tracking needed.
  // Once we win, IsBuyBoxWinner becomes true and main algorithm takes over.

// Use winning competitor if we're losing, or nearest featured if we're winning
  const competitor =
    winningCompetitor ||
    offers
      .filter((o) => o.SellerId !== sellerId && o.IsFeaturedMerchant)
      .sort(
        (a, b) =>
          Math.abs(landedPrice(a) - landedPrice(myOffer)) -
          Math.abs(landedPrice(b) - landedPrice(myOffer)),
      )[0];

if (!competitor) return context;

// Note: When winning with no competitor, we stay put. Jumping to ceiling would
  // cause ping-pong with suppression path. Not worth the complexity to track.

// Cap ceiling with competitive threshold if available
  const threshold = summary?.CompetitivePriceThreshold?.Amount;
  const ceiling = threshold
    ? Math.min(listing.ceiling, threshold)
    : listing.ceiling;
  const maxLanded = ceiling + shipping;

// Learn and suggest price
  const suggestedLanded = learnBoundaries(
    context,
    myOffer,
    competitor,
    maxLanded,
  );

if (suggestedLanded !== null) {
    const price = clamp(suggestedLanded - shipping, listing.floor, ceiling);
    listing.set({ price: round(price) });
  }

return context;
}

function learnBoundaries(context, myOffer, competitor, maxLanded) {
  const { asin, condition } = context.listing;
  const key = boundaryKey(asin, condition, competitor);
  const bounds = context.store.get(key) || { w: null, l: null, ts: null };

// Reset stale boundaries (24h TTL handled by Redis, but also check here)
  const now = Date.now();
  if (bounds.ts && now - bounds.ts > 24 * 60 * 60 * 1000) {
    bounds.w = null;
    bounds.l = null;
  }

const myLanded = landedPrice(myOffer);
  const compLanded = landedPrice(competitor);

// Percentage delta: negative means we're cheaper
  const delta = (myLanded - compLanded) / compLanded;
  const winning = myOffer.IsBuyBoxWinner;

// Update boundaries
  if (winning) {
    if (bounds.w === null || delta > bounds.w) {
      bounds.w = delta;
    }
    // Invalidate losing boundary if we won at a higher delta
    if (bounds.l !== null && delta >= bounds.l) {
      bounds.l = null;
    }
  } else {
    if (bounds.l === null || delta < bounds.l) {
      bounds.l = delta;
    }
    // Invalidate winning boundary if we lost at a lower delta
    if (bounds.w !== null && delta <= bounds.w) {
      bounds.w = null;
    }
  }

bounds.ts = now;
  context.store.set(key, bounds);

// Anti-jitter: stop optimizing when boundaries converged
  if (bounds.w !== null && bounds.l !== null) {
    const gap = bounds.l - bounds.w;
    if (gap < CONVERGENCE_THRESHOLD && winning) {
      // Boundaries converged and we're winning - stay put
      return null;
    }
  }

// Calculate max delta from threshold
  const maxDelta = (maxLanded - compLanded) / compLanded;

// Suggest next price
  let suggestedDelta;
  if (winning) {
    suggestedDelta = suggestWhenWinning(delta, bounds, maxDelta);
  } else {
    suggestedDelta = suggestWhenLosing(delta, bounds);
  }

return round(compLanded * (1 + suggestedDelta));
}

function suggestWhenLosing(currentDelta, bounds) {
  if (bounds.w === null) {
    // No winning boundary - explore downward
    return exploreLower(currentDelta);
  }
  // Bisect between current and winning boundary
  return (currentDelta + bounds.w) / 2;
}

// Explore higher prices (increase percentage delta)
function exploreHigher(delta) {
  if (delta < -0.02) {
    // We're more than 2% below - halve the gap
    return delta / 2;
  } else if (delta < 0) {
    // We're slightly below - try matching
    return 0;
  } else if (delta < 0.01) {
    // We're at or slightly above - try 1% above
    return 0.01;
  } else {
    // Double our premium
    return delta * 2;
  }
}

// Explore lower prices (decrease percentage delta)
function exploreLower(delta) {
  if (delta > 0.02) {
    // We're more than 2% above - halve it
    return delta / 2;
  } else if (delta > 0) {
    // We're slightly above - try matching
    return 0;
  } else if (delta > -0.01) {
    // We're at or slightly below - try 1% below
    return -0.01;
  } else {
    // Double our discount
    return delta * 2;
  }
}

function boundaryKey(asin, condition, competitor) {
  return `bounds:${asin}:${condition}:${competitor.SellerId}`;
}

// Note: Key uses condition but not subcondition. The algorithm learns empirically
// what delta works against each competitor - subcondition advantage is captured
// in win/lose outcomes.

function landedPrice(offer) {
  return (offer.ListingPrice?.Amount || 0) + (offer.Shipping?.Amount || 0);
}

function clamp(value, min, max) {
  return Math.max(min, Math.min(value, max));
}

function round(value) {
  return Math.round(value * 100) / 100;
}