Automating an eBay Resale Business, End to End
I run a resale business, Southeast Surplus Co. The economics of resale are simple: the money is made sourcing and pricing, and everything between those two — photos, listings, bookkeeping, buyer messages — is overhead. So over the past year I've been systematically automating the overhead.
The photo pipeline
Every item gets photographed on my phone. A pipeline normalizes the photos, strips the metadata (phone photos embed GPS coordinates — which means every casual eBay listing photo taken at home broadcasts where you live), renames everything to a consistent scheme, and pushes them to cloud object storage where the listings reference them. When I audited my old listings and realized how many location-tagged photos I'd published, I purged and re-uploaded every single one. If you sell online from your home: check your photo metadata.
Listing creation via API
eBay's seller UI is fine for one listing and miserable for twenty. I registered a developer keyset and now create listings through the Sell APIs: a CSV describes the item, a script builds the inventory record, attaches photos, sets category-required item specifics, applies my shipping/return policies, and publishes. A batch of twenty items that used to take an afternoon now takes minutes, and the listings are more consistent than anything I produced by hand.
The APIs have sharp edges — category-required "item aspects" that differ by category, service codes that don't match their documentation names, transient errors that just want a retry. The scripts absorb all of that now.
Knowing whether I'm actually making money
Gross revenue is a vanity number in resale. Real profit is gross minus fees, minus shipping labels, minus label corrections (carriers re-weigh packages and bill you the difference — that was costing me hundreds before I could see it), minus cost of goods. I built a small SQLite database that syncs orders and every financial transaction from eBay's APIs nightly, then produces a per-item P&L: what each item really netted, and my true ROI on every sourcing decision.
Buyer messages, without living in the eBay app
A small service polls for new buyer messages and forwards them to me on Telegram; I reply in the chat and it posts the answer back through the API. It also has a rules engine for the questions every reseller gets daily — "do you combine shipping?" — though I keep auto-reply off and approve everything for now.
What I learned
- Automate the pipeline, not the judgment. Software does photos, listings, and books. Sourcing and pricing decisions stay human.
- Instrument before you optimize. The P&L database changed my pricing strategy more than any listing tweak — you can't fix what you can't see.
- Privacy is a process, not a setting. Metadata scrubbing is now a non-optional pipeline stage, not something I remember to do.