Connect suppliers FTP Servers with our Shopify

About us We run a Shopify store with our own warehouse and source goods from around five suppliers. Our goal is to automate as many operational processes as possible. Current situation Our suppliers give us SFTP access where they regularly upload file feeds containing stock levels, purchase prices and product master data (CSV/XML, format differs per supplier). We currently do not evaluate this data systematically. What we want built A middleware layer that automatically ingests these feeds, normalises them, and makes them usable in our own database for purchasing decisions. Key architectural principle: Supplier stock is procurement intelligence, not sellable inventory. It must never be written into Shopify inventory — our sellable stock is exclusively what physically sits in our own warehouse. Applications proposing a direct feed → Shopify inventory sync have misunderstood the brief. Scope of work 1. Feed ingestion One workflow per supplier, scheduled roughly 4× daily SFTP connection, parsing of CSV/XML in varying formats Protection against partially uploaded files (file size stability check or marker file) File age validation — no processing of stale feeds 2. Plausibility checks (mandatory, not optional) Abort if row count deviates more than 20 % from the previous run Abort if more than 30 % of all SKUs drop to zero stock simultaneously Failures must trigger a notification, never a silent import 3. Data model (Postgres) Current state per supplier and article History for price and stock development Mapping table: our SKU ↔ supplier article numbers Matching primarily via EAN/GTIN, not article numbers Defined handling of unmatchable rows (reporting rather than discarding) 4. Analytics / business value Supplier comparison: which supplier carries an article at what price Reorder suggestions combining sales velocity (Shopify), own stock and supplier availability Alerts on purchase price increases (margin protection) Delisting detection (article disappears from feed or stays at zero) 5. Shopify integration Read-only: retrieving sales data and product master data for demand calculation Exclusively via the GraphQL Admin API. The REST Admin API has been legacy since October 2024 and is not an option. Cost-based rate limits must be respected; use Bulk Operations for large volumes 6. Operations Deployment via Docker Compose on our server Logging and alerting on feed failures (email or messenger) Documentation that enables us to connect further suppliers ourselves Technology Our proposal — well-reasoned counter-proposals are welcome: n8n (self-hosted via Docker) for orchestration and scheduling Postgres as database Python for parsing large feeds (n8n holds data in memory; beyond roughly 50,000 rows parsing should be offloaded) Shopify GraphQL Admin API Out of scope No writing of supplier stock into Shopify No storefront work, no theme development No ERP and no warehouse management system Requirements Demonstrable experience with e-commerce data integration Hands-on experience with the Shopify Admin API (GraphQL) n8n or comparable workflow automation SQL and data modelling Python Docker Fluent German or English Process and award We award in two stages: Pilot: Integration of one supplier including data model, plausibility checks and deployment. Fixed price. Rollout: Integration of the remaining four suppliers plus analytics, after a successful pilot. For your estimate: the first supplier is by far the most effort, each additional one considerably faster. Your application should include Two or three comparable projects, ideally with code or repository Your assessment of the proposed architecture — including if you think it is wrong How you would handle suppliers that do not provide EANs Hourly rate or fixed price for the pilot, plus your availability Handover Source code in our Git repository Docker Compose setup, running on our infrastructure Technical documentation and a guide for connecting further suppliers One handover session Credentials for the supplier SFTP servers and for Shopify will be provided after contract signature.