WorkHeadlinerJun 2026
Proof Market Maker
An always-on market-making bot with inventory control, self-healing reconnects and a two-stage kill switch, plus an operator dashboard.
The ops dashboard: PnL estimate, inventory, feed health, open orders, audit log and the RUN / SOFT / HARD kill switch
- The ops dashboard on a phone
01What I built
A market maker for the Proof.trade paper-trading competition, finished 2026-06-24. It quotes both sides of a market continuously, leans its prices to sell down inventory when it gets one-sided, pauses and re-syncs when the exchange connection drops without leaving stray orders, and has a two-stage kill switch: soft (stop quoting) and hard (flatten everything and stand down). It was built to survive dropped connections, frozen feeds, rate limits and crashes, with a crash-recovery journal and a stale-feed watchdog. No real money: development network, play funds.
Alongside it, a read-only operator dashboard (proof-ops-dashboard) that shows PnL, inventory, feed health, open orders and the audit log live every two seconds, with the kill switch behind fail-closed basic auth. The kill-switch write never touches a service-role key: the server action presents a control-scoped secret to a Supabase Edge Function, so a leaked dashboard secret can only flip the switch, never forge bot state. A cloud outage can never prevent a stop.
02What I learned
Reliability engineering is mostly deciding what happens when things go wrong, in advance. The interesting parts of this project are not the pricing strategy, which is a few lines, but the watchdog, the token bucket, the journal and the rule that a stale cloud value never overrides a local hard stop.
I also learned how to think about a trust model in plain terms: what can each credential do if it leaks, and is that the smallest thing it could do. That is a question I now ask of every integration a partner proposes.
03Built with AI
Built by Claude Code from a spec that led with failure modes rather than features. The verification I trusted was the scripted demo (quote, force a connection drop, recover, keep going) and live QA of the dashboard kill switch, which surfaced a real gotcha: credentials embedded in the URL silently break the poll in Chromium. That went into the README.
Solana relevance
Market making is the job that keeps on-chain venues liquid, and liquidity depth is what Solana's tokenized-equity venues and perps are judged on. Building one, even on paper, taught me the operator's view of a venue: feed reliability, order-cancel latency and kill-switch design matter more to a market maker than headline throughput. That is the conversation I would have with a liquidity partner.