render-background-workers

Render Background Workers

This skill explains worker services on Render: processes that consume jobs from a queue instead of serving HTTP. Pair with render-blueprints, render-env-vars, and render-networking when wiring render.yaml and private connectivity.

When to Use

• Designing or debugging queue-backed workers (Celery, Sidekiq, BullMQ, Asynq, etc.)
• Choosing between a worker, Cron Job, or Workflow for background work
• Configuring Render Key Value as a broker (not a cache) with correct eviction policy
• Implementing graceful shutdown so in-flight jobs are not lost on deploy

Per-framework setup and signal-handling detail: references/queue-framework-setup.md, references/graceful-shutdown.md.

How Workers Work

• Long-running services with no inbound (HTTP) traffic. Render does not expose a public URL or internal hostname for workers the way it does for web or private services—workers cannot receive private network traffic directed at them.
• The typical pattern is a poll loop: the process connects to a queue backend (often Render Key Value, Redis-compatible Valkey 8) and pulls jobs.
• Workers can initiate outbound connections on the private network—to PostgreSQL, Key Value, private services, web services (internal URLs), and the public internet—subject to your plan and firewall rules.

Queue Framework Overview

Framework	Language	Queue backend	Notes
Celery	Python	Redis / Key Value	Most common Python task queue
Sidekiq	Ruby	Redis / Key Value	Standard for Rails
BullMQ	Node.js	Redis / Key Value	Modern Node queue (Redis-based)
Asynq	Go	Redis / Key Value	Go async task processing
Oban	Elixir	Postgres (not Redis)	Queue stored in the database

Pairing with Key Value

• Use Render Key Value as the job broker when your framework expects Redis.
• Set maxmemory policy to noeviction. allkeys-lru and similar policies are for caches; evicting queue keys drops jobs.
• Wire REDIS_URL (or your framework’s equivalent) via fromService with type: keyvalue and property: connectionString in the Blueprint.
• Blueprints require ipAllowList on Key Value—include the CIDRs that should reach the instance (often [] for private-network-only access; see render-blueprints / Key Value field reference).