Marketplace Rollout Plan

Compliance-first marketplace integration

Six phases prioritized by data source risk level. Low-risk official APIs first, partnerships and user-contributed data models second, high-risk platforms deferred.

6
Phases
12-month horizon
3
Low-Risk First
Official API access
32
Blockers
0 resolved
7
Marketplaces
Target coverage
Timeline
W1–2
W3–4
W5–6
W7–8
W9–10
W11–12
M4
M5
M6
M7–8
M9–10
M11–12
eBay Browse API
Amazon PA-API
Etsy Open API v3
Browser Extension
Mercari & Vinted
FB/CL
Phase Details

Rollout phases by risk level

Phase 1Planning

eBay

Low RiskWeeks 1–6

Lowest compliance risk. Official API with rich data. Serves dual role as source marketplace and benchmark pricing via sold comps. eBay Partner Network enables affiliate revenue from day one.

Access Method
Browse API + Partner Network
Primary Use
Source + Benchmark
Endpoints / Integrations
item_summary/searchitem/{item_id}get_items_by_item_groupSold/completed items filter
Blockers
5 remaining
0/5
Compliance Guardrails (5)
  • No AI/ML training on eBay data without written consent
  • No redistribution of restricted pricing data in bulk
  • FTC deceptive pricing compliance — show real sold comps
  • Data minimization — store only listing metadata
  • Audit log every API call
Go / No-Go Criteria (6)
  • Production API keys approved
  • ≥100 listings/day for top 10 models
  • ≥5 comps per product for 80%+ of catalog
  • Rate limits confirmed for 15-min polling
  • Affiliate link generation working
  • End-to-end pipeline tested
Phase 2Planning

Amazon

Low RiskWeeks 4–8

Low risk via affiliate-oriented API. Not a source marketplace — provides new-price reference ceiling for used item valuations. Amazon Associates generates additional affiliate revenue.

Access Method
Product Advertising API v5
Primary Use
Benchmark Pricing
Endpoints / Integrations
SearchItemsGetItemsGetBrowseNodes
Blockers
4 remaining
0/4
Compliance Guardrails (5)
  • Active affiliate link required on every Amazon reference
  • 3 qualifying sales needed within 180 days for PA-API
  • No direct scraping — PA-API only
  • 24-hour data freshness requirement
  • Display "Prices from Amazon" attribution
Go / No-Go Criteria (4)
  • PA-API access approved
  • ≥90% ASIN coverage of product catalog
  • Price data returning correctly
  • 24-hour refresh cycle automated
Phase 3Planning

Etsy

Low-Med RiskWeeks 6–12

Official API exists but designed for shop management, not market intelligence. Strong fit for vintage cameras and collectibles. Requires proactive Etsy DevRel communication to clarify acceptable use before scaling.

Access Method
Open API v3 (OAuth 2.0 PKCE)
Primary Use
Source — Vintage & Collectibles
Endpoints / Integrations
listings/activelistings/{listing_id}shops/{shop_id}listings/{id}/imagestaxonomy/seller-taxonomy/nodes
Blockers
6 remaining
0/6
Compliance Guardrails (5)
  • No analytics/ML on API data without authorization
  • No reselling or bulk-sharing of API data
  • No combining Etsy user data with third-party data
  • Conservative polling with 50% rate-limit headroom
  • Position as seller pricing tool, not market intelligence
Go / No-Go Criteria (6)
  • API keys approved and working
  • Etsy DevRel outreach initiated
  • ≥70% category taxonomy mapped
  • OAuth PKCE flow working end-to-end
  • ≥50 relevant listings/day
  • HARD STOP if Etsy explicitly rejects use case
Phase 4Planning

FB MP · CL · Vinted · Mercari

Medium RiskMonths 4–6

Unlocks marketplaces without official APIs via user-initiated data collection. Shifts compliance burden from Arbitr scraping to user's own browsing. Requires legal counsel review and Chrome Web Store approval.

Access Method
Browser Extension (User-Initiated)
Primary Use
Source — All Categories
Endpoints / Integrations
Chrome content scripts per platformExtension ↔ backend messaging APIUser consent management APIManual deal submission endpoint
Blockers
7 remaining
0/7
Compliance Guardrails (6)
  • Explicit user opt-in required — no default-on collection
  • Data minimization — listing metadata only, no seller PII
  • No automated crawling — only pages user actually visits
  • One-click opt-out + data deletion on request
  • GDPR compliance — right to erasure, data portability
  • Legal counsel review required before launch
Go / No-Go Criteria (7)
  • Legal counsel greenlight
  • Privacy policy published
  • Chrome Web Store approval
  • User consent flow tested & approved
  • Beta tested with ≥10 users
  • End-to-end pipeline: extension → backend → valuation
  • HARD STOP if legal counsel advises against
Phase 5Planning

Mercari & Vinted

Medium RiskMonths 7–12

High-value targets without public APIs. Business development approach: propose driving buyer traffic in exchange for data access. Browser extension data from Phase 4 provides proof of user demand.

Access Method
Partnership / Data License
Primary Use
Source — Electronics & Fashion
Endpoints / Integrations
Partnership API (TBD)Affiliate revenue share (TBD)Browser extension fallback (Phase 4)
Blockers
5 remaining
0/5
Compliance Guardrails (4)
  • Partnership terms must not compromise core product
  • No unauthorized data access during negotiation
  • Continue browser extension data in parallel
  • Category expansion requires product catalog update
Go / No-Go Criteria (4)
  • At least one partnership conversation initiated
  • ≥50 daily listings via browser extension validates demand
  • Legal terms acceptable
  • Technical integration feasible within 4–6 weeks
Phase 6Deferred

Facebook MP & Craigslist

High RiskMonth 12+

Enormous user value but unacceptable compliance risk for early-stage company. Facebook: no API, login-walled, aggressive enforcement. Craigslist: $60.5M+ in enforcement judgments. Deferred until external triggers.

Access Method
Deferred — Partnership / User-Submitted
Primary Use
Source — Local Deals
Endpoints / Integrations
User-submitted deal URLsCommunity deal feeds (Discord/Telegram)Browser extension (Phase 4 interim)
Blockers
5 remaining
0/5
Compliance Guardrails (5)
  • No direct scraping under any circumstances
  • Meta v. Bright Data / Craigslist v. RadPad ($60.5M) precedents
  • GDPR/CCPA full compliance before processing any personal data
  • $50K+ legal reserve required before activation
  • Wait for legitimate API pathway or partnership
Go / No-Go Criteria (5)
  • Meta announces Marketplace API or partnership program
  • OR Craigslist policy changes
  • OR Arbitr raises Series A (legal budget)
  • OR legal counsel confirms alternative access method
  • Full data subject access request handling implemented
Compliance Matrix

Platform risk assessment

Platform
API Risk
Scraping Risk
Enforcement
Overall
eBay
Low
N/A
Low
Low
Amazon
Low
High
High
Low-Med
Etsy
Low-Med
High
Medium
Low-Med
Mercari
N/A
High
Medium
Medium
Vinted
N/A
High
Medium
Medium
Facebook MP
N/A
High
High
High
Craigslist
N/A
High
High
High
Immediate Actions

Next steps this week

01critical

Register eBay Developer Account

Submit application with "seller pricing comparison tool" use case

Owner: Engineering
02high

Register Amazon Associates

Begin affiliate qualification process for PA-API access

Owner: Growth
03critical

Build Product Catalog v1

50 camera models + 15 console SKUs with specs and price ranges

Owner: Product + Eng
04critical

Set Up Database Schema

Products, comparables, valuations, listings, alerts tables

Owner: Engineering
05high

Begin eBay API Integration

OAuth flow, search endpoint, sold items comp retrieval

Owner: Engineering
06medium

Engage Legal Counsel

Find counsel for Phase 4 browser extension review. Needed by Month 3.

Owner: CEO