{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,31]],"date-time":"2026-10-31T06:34:11Z","timestamp":1793428451943,"version":"4.5.0"},"posted":{"date-parts":[[2026]]},"group-title":"SSRN","reference-count":0,"publisher":"Elsevier BV","license":[{"start":{"date-parts":[[2026,1,1]],"date-time":"2026-01-01T00:00:00Z","timestamp":1767225600000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"abstract":"<jats:p>In this work, we developed Quantx, an exchangestyle paper-trading workspace for National Stock Exchange of India (NSE) equities in which simulated orders are matched locally against streamed market depth and protected by transactional state snapshots. The system is organized as four tiers: a React client, a FastAPI service tier, an in-process market-data decoding and matching tier, and a PostgreSQL ledger paired with a Redis quote cache. Its foundational design principle is a strict architectural boundary between a marketdata plane, which may only read authentication, instrument, and quote data from upstream providers, and an accounting plane, which alone creates orders, fills, statutory charges, cash movements, positions, and recovery snapshots; paper orders are never routed to an external broker or exchange order interface. Inside this boundary, the system normalizes prices to tick size, validates circuit, board-lot, and freeze constraints, walks five-level bid and ask depth with partial fills, applies product-aware brokerage and Indian statutory charges, discards duplicate and older-timestamp packets, refuses market orders when depth is stale, and provides atomic SafePoint state rollback alongside non-destructive multi-modal What-If stress testing and a guardrailed non-advisory learning guide. We evaluated the integrated workflow against a last-price, zerocharge, arrival-order baseline (B0) across N = 50 scripted orders spanning Typical (N1 = 20), Boundary (N2 = 20), and Adversarial (N3 = 10 valid orders plus N adv = 50 injected fault events) scenario profiles on a live PostgreSQL 16.15 and Redis 7.4.11 stack. Quantx achieved zero ledgerreconciliation error (mean = 0.00 IN R, max = 0.00 IN R vs. B0 mean = 19,684.41 IN R, max = 227,398.32 IN R), zero fill-price deviation (0.00 IN R\/share vs. B0 1.60 IN R\/share across N f = 73 fills), zero charge deviation (0.00 IN R\/f ill vs. B0 33.08 IN R\/f ill), and zero adversarial fault leaks across all 50 injected disorder, staleness, idempotency, and ruleviolation events, while maintaining sub-millisecond quote ingestion (p99 = 0.06 ms) and sub-120 ms five-level match-andcommit latency (p50 = 71.02 ms, p99 = 118.02 ms). These results support the engineering feasibility of boundary-enforced local paper execution for NSE equity practice; they do not establish fidelity to live exchange queue priority, educational learning outcomes, or production brokerage readiness.<\/jats:p>","DOI":"10.2139\/ssrn.7670718","type":"posted-content","created":{"date-parts":[[2026,10,31]],"date-time":"2026-10-31T06:16:02Z","timestamp":1793427362000},"source":"Crossref","is-referenced-by-count":0,"title":["Quantx: An NSE Equity Paper-Trading Workspace with Boundary-Enforced Market Data, Depth-Based Local Order Matching, and Transactional SafePoint Recovery"],"prefix":"10.2139","author":[{"ORCID":"https:\/\/orcid.org\/0009-0006-3098-6175","authenticated-orcid":true,"given":"Bhavik","family":"Achotani","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"78","container-title":[],"original-title":[],"deposited":{"date-parts":[[2026,10,31]],"date-time":"2026-10-31T06:16:03Z","timestamp":1793427363000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.ssrn.com\/abstract=7670718"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026]]},"references-count":0,"URL":"https:\/\/doi.org\/10.2139\/ssrn.7670718","relation":{},"subject":[],"published":{"date-parts":[[2026]]},"subtype":"preprint"}}