# Allbirds — Fixing the Checkout That Slowed Down Under Traffic

> Allbirds serves millions of customers globally. Their checkout was inconsistent under traffic spikes — slow SQL joins were the culprit. We diagnosed it, fixed it, and Dockerized the whole stack so "works on my machine" stopped being a phrase anyone said.

## Project context

- Client: Allbirds
- Industry: Sustainable Footwear
- Year: 2023

## Challenge

Checkout response times spiked to 4–6 seconds under traffic loads that should have been entirely manageable. Heatmaps and session recordings showed clear abandonment at the payment step during high-traffic windows. The engineering team also battled constant staging-vs-production inconsistencies that made reproducing and fixing bugs a slow process.

## Solution

SQL audit of the entire checkout query path: identified 6 queries responsible for 80% of the latency. Added composite indexes on high-selectivity columns, rewrote 3 queries with proper eager loading to eliminate N+1 patterns, moved email sending into a background job queue. Dockerized the full stack — consistent environments from laptop to production. Checkout response times stabilized under 1.2 seconds even at peak.

## Services

- Web Development

## Published results

- <1.2s Checkout response time (peak) (vs 4–6s before)
- eliminated Environment bugs (post-Docker rollout)
- −55% Checkout abandonment (traffic spikes) (month post-fix)
- 6 Queries optimised (responsible for 80% latency)

## Benefits

- Checkout consistently under 1.2s even at peak
- Composite indexes + eager loading on all hot paths
- Docker stack — no more staging vs production surprises
- Background jobs handle all email and async operations

## Source and contact

- Canonical project page: https://qualityx.co/en/portfolio/allbirds-ecommerce-backend
- Discuss a related project on WhatsApp: https://wa.me/905392376734