ryan w tenney

Grubhub made couriers tap buttons to move a delivery forward; nobody else did. Courier Signals replaced the taps with the phone's own sensors — GPS, closing rate, and iOS Motion Activity — fused through a filter over the trip's state machine, where getting out of the car is the most informative event in a delivery and no geofence can see it.

The actor-based simulation that gave Grubhub's pre-production environment a heartbeat, rebuilt in the browser: statistically realistic diners, merchants, and couriers who actually drive real Chicago roads — offer, accept, reject, pocket veto — through a full simulated day of meal peaks, dispatch queues, and delivery stats.

The service that broke Grubhub Managed Delivery's deepest assumption — that the courier on a delivery is ours. Holds against our own dispatch, courier identities minted from an opaque provider id, masked phone numbers, and a full courier's worth of events emulated from webhooks — then re-pointed at an autonomous drone fleet as configuration, not a rewrite.

In-app navigation built on a routing graph deliberately stripped of everything guidance needs. Street names come back as a bit-packed side-car — a grammar of direction, base name, and street type over a front-coded dictionary, 2.6 bytes per segment against 76 — and maneuvers are derived per query from junction geometry, branch analysis, and name continuity, because a maneuver isn't a property any edge can store.

The map matcher behind Grubhub's courier tracking, rebuilt in the browser: a hidden Markov model over packed parameter arrays — quantized reference speeds, turn probabilities, quadtree candidate lookup — decoding a 1 Hz GPS stream whose errors are ray-traced through 17,000 real Chicago buildings using the GPS Urban Canyon physics, live against ground truth.

The courier-to-order assignment engine at Grubhub, rebuilt as an interactive bipartite graph: a totally unimodular MIP solved exactly by min-cost flow, an acceptance model structurally forbidden from seeing tips, and the offline simulation harness that proved two plausible objective improvements weren't — including one that posts the best acceptance rate on the board while stranding low-tip diners.

The delivery boundary generator I owned from inception at Grubhub, rebuilt in the browser: a CRP isochrone descended into every touched cell, buffered into a polygon via a raster distance field and marching squares, then simplified 95× — with the coverage and over-promise error measured on every query rather than assumed.

The combined geocoder and reverse geocoder I built on OpenStreetMap data at Grubhub — rejecting Google Maps over a caching restriction that turned a one-time cost per address into a recurring one — rebuilt in the browser: USPS Publication 28 standardization applied to both sides of the match, three inverted indexes that fail in different directions, parity-aware house-number interpolation, and a confidence tier honest enough to drive product behavior.

Interactive visualization of the merchant discovery design I led at Grubhub: CRP-partitioned road graph, per-cell boundary cliques, and precomputed merchant routing data driving an expanding radius search — animated on real OSM data for downtown Chicago, entirely in the browser.

The CRP routing engine behind Grubhub's Pathfinder service, rebuilt in the browser: partition a real OSM road network, compute boundary cliques live, then watch point-to-point queries escape their cell, hop across the overlay, and unpack into the shortest path.

Multi-tenant community incident reporting SaaS, grown from a system I built for my own neighborhood association. Rust on Lambda, SvelteKit frontend, and a layered spam-defense stack — including a proof-of-work-style upload authorization — that works without requiring reporters to create accounts.

WireGuard client for iOS and macOS with automatic tunnel failover. Fork of the official client adding failover groups: traffic-based health detection, seamless in-place config swaps inside the Network Extension, and hot-spare probes that preserve the Noise session for zero-handshake failover.

The local agent from my patent with Martello Technologies, rebuilt in the browser: a management client hardcoded to a single TCP port, pointed at every device on every customer network at once by binding each one to its own stable address inside 127.0.0.0/8 — with the on-demand setup sequence (authorize, port forward down the probe's reverse tunnel, device proxy, nonce-matched meet-in-the-middle) running hop by hop.

Network-wide redirect of twitter.com/x.com links to xcancel, configured by a zero-backend web wizard: it interviews you about your network, generates a root CA and wildcard server certs entirely in the browser with node-forge, tailors nginx/Caddy + Docker Compose + DNS config to your answers, and zips the whole deployment into a single download with JSZip.

Constraint solver that generated the final seating chart for my wedding. Because some problems deserve a proper optimizer.

TSP-optimized road trip visiting every German city with two or more umlauts. MIP formulation with PuLP/CBC, road routing via Graphhopper on OSM data.

Ray-traced GPS visibility and multipath in real Midtown Manhattan: NYC Open Data footprints, IGS precise orbits parsed in the browser, image-method facade reflections, a 3D city view, and WLS position-error heatmaps — why your phone thinks you're two blocks away.

Self-hosted universal file management with full-text search across 1000+ formats, AI-powered enrichment, and complete version history. Think Paperless-NGX with complete file type freedom and integrated AI.

Lead maintainer (2014-2017) of the de facto standard for JVM application metrics. Captures JVM- and application-level metrics so you know what's going on.

Custom PCB design for an 8-port USB-C charging station that automatically stops charging at 80% state-of-charge. Detects the CC-to-CV transition in the lithium-ion charge profile to infer battery level without device communication.

Solver for a minimax graph clearing problem, built for the ACP Summer School 2018 competition — the only submission within the time limit.

Spring integration for Dropwizard Metrics. Instruments annotated methods on Spring beans through dynamic proxies and bytecode generation. Used by American Express, Apple, Dealer.com, eHarmony, ESPN, Orbitz, and more.

Java library for generating Apple Passbook (.pkpass) files.