Building with eBay Data in 2026 — 6 Endpoints, 10 Markets, and the Billing Trap Nobody Warns You About

Search query └── Listing page (contains N listing cards) └── Listing card (title, price, condition, seller, item link) └── Item detail (images, specifics, availability, description) └── Seller profile (identity, feedback score, positive rate) └── Seller listings (inventory, page by page) └── Seller feedback (buyer comments, ratings) └── Product reviews (review text, rating, author) 

pip install requests python-dotenv 

# .env SERPENT_API_KEY=your_key_here 

# ebay_client.py import requests import os API_KEY = os.getenv("SERPENT_API_KEY") BASE = "https://apiserpent.com/api/ebay" HEADERS = {"X-API-Key": API_KEY} def get(endpoint, params): r = requests.get(f"{BASE}{endpoint}", params=params, headers=HEADERS, timeout=30) r.raise_for_status() return r.json() 

def search_listings(query, marketplace="EBAY_US", locale="en-US", page=1): """ Returns listing cards: title, price, condition, shipping, seller identity, item link. 10 supported marketplace/locale pairs: EBAY_US/en-US EBAY_GB/en-GB EBAY_DE/de-DE EBAY_AU/en-AU EBAY_IT/it-IT EBAY_FR/fr-FR EBAY_CA/en-CA EBAY_ES/es-ES EBAY_NL/nl-NL EBAY_PL/pl-PL Rate: $0.40/1K calls at Default tier """ return get("/search", { "q": query, "marketplace_id": marketplace, "locale": locale, "page": page }) # Example results = search_listings("vintage camera", "EBAY_DE", "de-DE") for listing in results.get("listings", []): print(listing["title"], listing["price"], listing["currency"]) 

def get_item(item_id, include_description=False): """ Returns price, images, item specifics, availability, seller. Add include_description=1 to get the full seller HTML description. Description calls: $1.50/1K (3.75x the standard rate). If description unavailable but core item exists, standard rate applies. Use include_description only when your pipeline needs it — most price monitoring workflows don't. """ params = {"item_id": item_id} if include_description: params["include_description"] = 1 return get("/item", params) # Price check without description (standard rate) item = get_item("v1|123456789012|0") print(item["price"], item["currency"], item["condition"]) # With full description (description rate) item_full = get_item("v1|123456789012|0", include_description=True) print(item_full.get("description", "")[:200]) 

def get_seller_profile(seller_username): """ Returns: seller identity, feedback score, positive feedback rate, profile link. Useful for: trust scoring, seller monitoring, marketplace research, fraud detection signals. Rate: $0.40/1K calls """ return get("/seller", {"seller": seller_username}) profile = get_seller_profile("vintage_camera_shop") print( profile["feedback_score"], profile["positive_feedback_rate"], profile["member_since"] ) 

def get_seller_inventory(seller_username, page=1): """ Returns structured item cards from a seller's active listings. Paginate to collect the full inventory. For large inventories (100+ pages), use a background job when listed in the API catalog — only served pages are charged. Rate: $0.40/1K calls or served pages """ return get("/seller/items", { "seller": seller_username, "page": page }) def collect_all_seller_items(seller_username, max_pages=10): """Collect a seller's full inventory page by page.""" items = [] for page in range(1, max_pages + 1): data = get_seller_inventory(seller_username, page) page_items = data.get("items", []) if not page_items: break items.extend(page_items) print(f"Page {page}: {len(page_items)} items") return items 

def get_product_reviews(product_id): """ Returns: review text, star rating, author username, date. Note: requires an eBay catalog product_id (e-pid), not a listing item_id. These are different identifiers. Rate: $0.40/1K calls """ return get("/product/reviews", {"product_id": product_id}) reviews = get_product_reviews("235190997") for review in reviews.get("reviews", []): print(review["rating"], review["title"], review["date"]) 

def get_seller_feedback(seller_username, page=1): """ Returns: feedback entries with buyer username, positive/negative/neutral rating, comment text, date. Useful for: sentiment analysis, seller trust scoring, fraud signals, marketplace research. Rate: $0.40/1K calls """ return get("/seller/feedback", { "seller": seller_username, "page": page }) feedback = get_seller_feedback("vintage_camera_shop") for entry in feedback.get("feedback", []): print(entry["rating"], entry["comment"][:80]) 

import time from datetime import datetime def run_price_monitor(keywords, marketplaces, output_file="prices.jsonl"): """ For each keyword × marketplace pair: 1. Search listings (discovery) 2. Get item detail for top N results (enrichment) 3. Log price, condition, seller, timestamp Cost at Default tier ($0.40/1K): - 1 search call + N item calls per keyword/market pair - For 10 keywords × 3 markets × top-5 items: 30 search calls + 150 item calls = 180 calls total 180 / 1000 × $0.40 = $0.072 per run """ import json results = [] for keyword in keywords: for marketplace_id, locale in marketplaces: # Layer 1: Search search_data = search_listings(keyword, marketplace_id, locale) listings = search_data.get("listings", [])[:5] # top 5 only for listing in listings: item_id = listing.get("item_id") if not item_id: continue # Layer 2: Item detail (no description — not needed for price monitoring) try: item = get_item(item_id) record = { "timestamp": datetime.utcnow().isoformat(), "keyword": keyword, "marketplace": marketplace_id, "item_id": item_id, "title": listing["title"], "search_price": listing.get("price"), "item_price": item.get("price"), "currency": item.get("currency"), "condition": item.get("condition"), "seller": listing.get("seller"), "availability": item.get("availability"), } results.append(record) # Write incrementally so partial runs aren't lost with open(output_file, "a") as f: f.write(json.dumps(record) + "\n") except Exception as e: print(f"Item {item_id} failed: {e}") time.sleep(0.1) # gentle rate limiting return results # Run it KEYWORDS = ["vintage camera", "film camera", "polaroid camera"] MARKETS = [ ("EBAY_US", "en-US"), ("EBAY_GB", "en-GB"), ("EBAY_DE", "de-DE"), ] data = run_price_monitor(KEYWORDS, MARKETS) print(f"Collected {len(data)} price records")