Tracking Costco gas prices
A hacker meticulously built a system to track gas prices at 600 Costco locations by reverse-engineering their API and using TimescaleDB, offering a granular view of how a major retailer adjusts to global fuel market shifts. The project quickly became a fascinating case study on practical data engineering, Costco's opaque pricing strategies, and the perennial Hacker News debate over whether the juice is worth the squeeze for penny-pinching motorists. Ultimately, the author made the entire system personally irrelevant by buying a Tesla, adding a humorous twist to an otherwise serious data-driven endeavor.
The Lowdown
During a period of heightened fuel market volatility, one intrepid individual embarked on a personal mission to demystify Costco's notoriously low gas prices. Frustrated by the lack of centralized data, the author engineered a comprehensive tracking system to monitor gas prices across nearly every Costco warehouse in the United States, providing a real-time, historical perspective on pricing dynamics.
- Motivation: Living between two Costcos and observing rising gas prices during a 'global fuel crisis,' the author sought to understand Costco's pricing behavior and its ability to maintain gas as a loss leader.
- Data Acquisition Ingenuity: The core of the project involved cleverly reverse-engineering Costco's internal APIs (
AjaxGetGasPricesServiceandAjaxWarehouseBrowseLookupView) to programmatically extract current gas prices, addresses, and coordinates for all US locations. - Technical Stack: A Python script swept the country using a grid of coordinates to query the API, storing the time-series data in TimescaleDB. A Next.js application with Tailwind then served a live, searchable dashboard to visualize the information.
- Key Findings: Analysis of 155 days of data revealed that Costco, despite its unique pricing model, was not immune to market forces, with prices fluctuating in response to global events. Over the period, cuts in price slightly outnumbered hikes.
- Personal Irony: In a comedic turn, after perfecting the system to save a few cents per gallon, the author acquired a Tesla, rendering the need for gas price tracking obsolete for their personal use.
This project stands as a testament to the power of personal initiative in data collection and analysis, turning a common consumer dilemma into an impressive display of technical skill, even if the personal motivation eventually evaporated.
The Gossip
Crisis Contention
A significant portion of the discussion revolved around the author's use of the term 'Global Fuel Crisis' in the title. Many commenters argued that a 26% increase in US gas prices, while annoying, did not constitute a 'crisis' compared to historical events or situations in other countries. The author responded, clarifying that the term was adopted from widespread media description of the 2026 Strait of Hormuz situation, not a political agenda.
Costco's Commerce Conundrum
The debate over whether Costco gas is truly a 'loss leader' was a major theme. Some users, referencing insider anecdotes or business podcasts, argued Costco avoids loss leaders, instead selling gas at a minimal margin or just above cost due to their purchasing power and operational efficiency. Others contended that, like their rotisserie chickens or hot dogs, gas serves as a draw to encourage membership and in-store purchases, functioning as an effective loss leader even if not officially labeled as such.
GasBuddy's Gaps and Granularity
Commenters discussed existing gas price tracking services like GasBuddy. While some praised GasBuddy's extensive data and techniques to ensure accuracy, the author clarified their project's necessity by highlighting that GasBuddy relies on user-reported data, which can occasionally be inaccurate. The discussion underscored the value of directly-sourced, API-driven data for precise, real-time information.
Valuing Vigor Vs. Vehicle Variance
Many users debated the practical value of the effort involved in seeking out the cheapest gas. While some argued that the time spent waiting in lines or making detours for a few cents' saving wasn't worth it for them, others, facing tighter budgets, found such savings significant. The conversation also touched on factors like 'Top Tier' gas quality (which Costco offers) and regional pricing peculiarities, particularly in California, where specific fuel blends and taxes inflate prices.