Full-Stack Notes: Shipping Stock Picks-Style Paper Trading Loops

Not financial advice. Verify claims independently.

A hire-friendly checklist for paper fills, watchlists, and realtime fan-out without live brokerage risk.

From the public realtime drawing set:

OpenAI DevDay lands Tuesday, Sep 29, 2026 — useful calendar context for anyone shipping AI-assisted tooling into trading or fintech client apps this week.

Paper loops win when they feel real:

Realtime quotes with honest lag indicators
Deterministic paper fills (documented rules, not vibes)
Watchlists + alerts that survive AMC bursts
AI assist (post-DevDay) only behind human approval

Stack sketch

Fan-out service with symbol sharding
JS/RN client with Skia-friendly tapes
Feature flags for earnings banners
Affiliate-ready CTA back to the practice app

Ship the loop; keep live brokerage behind a separate, disclosed door.

Not financial advice. Verify claims independently.