● BUILT FOR HIGH-VELOCITY BOOKSELLERS
Know every book.
Control every dollar.
Replace disconnected spreadsheets and seller tools with one operating system for receiving, rapid listing, FBA workflows, reconciliation and realized profit.
- List books in one keyboard-first workflow
- Trace every physical copy from purchase to sale
- See actual profit after Amazon fees and COGS
STOP LOSING TIME BETWEEN TOOLS
Your inventory should not live in five different places.
When purchases, condition notes, labels, shipments and fees are disconnected, sellers lose traceability and cannot confidently measure profit.
Explore every connected workflow →Fragmented operations
- Purchase costs separated from listings
- Physical locations tracked manually
- Shipment discrepancies found too late
- Estimated profit mistaken for actual profit
One lifecycle record
- Every unit carries its cost basis
- Every movement creates an event
- Expected and received units reconcile
- Realized profit uses actual financial data
ONE OPERATING SYSTEM
Your complete inventory lifecycle
Source & receive
Track acquisition source, purchase cost, incoming units and every physical copy.
List at speed
Scan ISBN, confirm condition, generate SKU, submit and queue the FNSKU label.
Pack & reconcile
Scan units into boxes, build inbound shipments and compare expected with received.
Know actual profit
Separate estimates from realized proceeds, Amazon fees, COGS and expenses.
EVERY DETAIL, ONE WORKSPACE
Built around the way inventory actually moves.
Rapid Listing Station
Move from ISBN scan to Amazon submission and FNSKU label with minimal mouse interaction.
- Catalog match confirmation
- Condition-note generation from verified facts
- Configurable SKU patterns
Unit-level traceability
Status alone is not enough. Every receipt, move, listing, pack, sale and return stays in the event ledger.
Warehouse control
Warehouse, zone, rack, shelf and bin locations with barcode-ready location codes.
FBA reconciliation
Compare what you packed and shipped against what Amazon received.
Financial truth
Revenue minus actual Amazon fees, COGS and expenses—not optimistic estimates.
AI that advises, never overrides
PHP calculates the facts. AI interprets structured results. Permissions, financial math and inventory safety remain deterministic.
Potential capital to recover: $187
OPTIONAL SOURCING INTELLIGENCE
S4ARBITRAGE AIFind opportunities. Track what actually happened.
S4Arbitrage evaluates eBay book opportunities using your profit targets and current inventory exposure. Purchased opportunities flow into S4Inventory, where receiving, listing, sale and realized profit complete the learning loop.
- Filter by minimum profit and ROI
- Consider inventory already owned or inbound
- Compare expected profit with realized outcomes
- No customer eBay API credentials or passwords
Actual fees and realized profit return to S4Arbitrage, improving future sourcing decisions.
Illustrative interface and figures—not a profit guarantee.
CALCULATE THE OPERATIONAL OPPORTUNITY
What could a faster listing workflow be worth?
Adjust the assumptions for your business. This is an illustrative estimate, not a performance guarantee.
36.1 hours potentially redirected each month
ILLUSTRATIVE SELLER GROWTH
See the business—not just the books.
When inventory movement and financial outcomes share one record, operators can identify what is selling, where capital is tied up, and what deserves attention next.
CUSTOMER TESTIMONIALS
Built to solve the work sellers talk about every day.
Fictional names, AI-generated portraits, and placeholder testimonials for layout demonstration. Replace them with verified customer statements before public launch.
The rapid listing flow finally gives our team one repeatable process from ISBN scan through label queue.
Seeing cost basis, Amazon fees, and realized profit together changes which inventory we choose to source again.
Shipment reconciliation makes it much easier to identify missing units and focus our follow-up work.
SECURE BY DESIGN
Your seller credentials stay server-side.
- Amazon authorization through OAuth consent
- Encrypted refresh and access tokens
- Workspace isolation and role-based permissions
- Audit logs for critical actions
- AI cannot bypass permissions or calculate financial truth
PLANS THAT GROW WITH YOU
Choose the workspace capacity you need.
Loading plans…
READY TO OPERATE WITH CLARITY?
Turn every sourced book into a traceable business outcome.
Start with the plan that fits your operation. Connect Amazon through secure authorization and build from your first received unit.