The problem
High-frequency options traders — scalpers — live in seconds. They place many orders, react to fast-moving prices, and judge a tool by whether it disappears into muscle memory.
For them, a slow interaction, a buried action, or an ambiguous state isn't a mild annoyance — it's money. The design challenge was to build a terminal dense enough to be powerful and clear enough to be safe, at the exact moment the stakes are highest.
Get it wrong and you lose your best, most active users. Get it right and you deepen the relationship with exactly the traders who matter most to the business.
The terminal, full view — annotated to show where the density is doing work rather than adding noise.
The design challenge
Four constraints shaped everything, and each one pulled against another:
- Density without chaos. Scalpers need prices, positions, order entry, and analytics on one screen. We held the layout fixed — every element in a constant place so it becomes muscle memory — and pushed deeper analytics behind progressive disclosure, so the default view stays scannable instead of drowning the trader in everything at once.
- Speed as a feature. We made the primary actions reachable in the fewest possible steps — preset lot sizes, a sticky order pad that never scrolls out of reach, and fast keyboard paths — so placing an order never competes with reading the market.
- Real-time state, read at a glance. Prices move constantly, so we communicated change through colour and a light flash on the value that changed, rather than redrawing the screen. A persistent P&L strip keeps "where do I stand right now" always visible. The goal: read the whole state in a glance, not a scan.
- Error prevention at speed. Speed is where costly mistakes happen, so the design has to catch them without slowing anyone down — unambiguous buy/sell colour coding, a deliberate confirm step on the order action, and guardrails against fat-finger quantities.
The Lab order ticket makes error-prevention-at-speed literal: you press and hold to confirm. Same idea, built as a working component you can try.
The core fast-action pattern — one-tap entry, presets, and the keyboard path.
Real-time state treatment: how "now" is made legible without a redraw.
How I led it
I didn't design every screen — I set the direction and defended the standard. My role was to keep the work honest to two things at once: what these traders actually need, and what the business needs from them. That meant running design critiques against real trader workflows, setting the interaction principles the team designed to, and aligning everything to FDSG so the terminal felt like part of the platform, not a bolt-on.
The clearest call I made was keeping the default view deliberately uncluttered. There's always pressure to surface everything on a power-user screen, but I held the principle that the terminal should disappear into muscle memory — so we defended progressive disclosure and resisted piling analytics onto the default layout, even when it was tempting.
That restraint is what let the density stay usable at speed.
The outcome
The proof is in the behaviour of the hardest-to-please users on the platform — they leaned in.
Taken together: the traders who are quickest to abandon a clumsy tool instead spent more time in it and placed more through it. For a trading product, that's the engagement signal that matters most.
A simple engagement chart — session duration or MAU trend across the period.