Investigate and Fix Intermittent Startup Issues in Dockerized Rails + Next.js Application

We have a containerized web application consisting of multiple services running through Docker Compose: Ruby on Rails API Next.js frontend Node.js services PostgreSQL Redis Sidekiq The application generally works, but we are experiencing intermittent startup and service communication issues that appear to be related to container orchestration and service readiness. Problem Summary The environment does not always start cleanly when bringing the stack up from scratch. Observed behavior includes: Rails occasionally failing to connect to PostgreSQL during startup Next.js frontend sometimes failing to reach the Rails API immediately after boot Node.js services occasionally starting before required dependencies are ready Sidekiq workers failing to connect to Redis on initial startup Some containers entering restart loops and eventually recovering after manual intervention Full stack working correctly after restarting one or more containers Expected Behavior A fresh environment should start successfully using a single command: docker-compose up without requiring: Manual container restarts Startup sequencing workarounds Waiting for services to become available before launching dependent containers Areas We'd Like Investigated Potential causes may include: Service dependency and startup ordering issues Missing or ineffective Docker health checks API availability timing between Next.js and Rails Database readiness and connection retry configuration Redis availability during Sidekiq startup Environment variable loading inconsistencies across containers Docker networking or service discovery issues Inefficient entrypoint or container initialization scripts Deliverables Investigate and identify the root cause Implement a reliable fix Improve startup consistency across environments Document any changes made Recommend best-practice improvements where appropriate Tech Stack Ruby on Rails React Next.js Node.js PostgreSQL Redis Sidekiq Docker / Docker Compose Budget Small initial task to troubleshoot and resolve this issue. Future Work We are looking for someone comfortable working across Rails, React/Next.js, Node.js, and Docker-based environments. If this task goes well, there may be additional work related to application performance, infrastructure improvements, CI/CD pipelines, and feature development.