I Stopped Paying $240/Year for Managed Redis — Dragonfly on a Free VM Handles 4x the Load

My side project hit $20/month on a managed Redis plan. For 1GB of cache. That's $240/year for what is essentially a hashmap with TTL.

I spent one afternoon migrating to Dragonfly on a free tier VM. Six weeks later: same p99 latency, zero cost, and the benchmark numbers are embarrassing for the paid option.

The benchmark that sold me

Same workload (80% GET / 20% SET, 1KB values), memtier_benchmark, 50 connections:

	Managed Redis (paid)	Dragonfly (free VM)
Throughput	~95K ops/sec	~390K ops/sec
p50 latency	0.8ms	0.3ms
p99 latency	4.1ms	1.2ms
Memory efficiency	baseline	~30% less for same data
Monthly cost	$20	$0

Dragonfly is multi-threaded (Redis is famously single-threaded), so it actually uses all 4 cores of the free ARM VM instead of pinning one.

Migration: the boring part (good)

It's wire-compatible. My REDIS_URL changed from the managed endpoint to the VM's private IP. That was the entire application change:

docker run -d --name dragonfly \
  --ulimit memlock=-1 \
  -p 6379:6379 \
  docker.dragonflydb.io/dragonflydb/dragonfly

Test with your existing client before switching DNS:

import redis
r = redis.Redis(host="10.0.0.15", port=6379)
r.set("migration-test", "works")
print(r.get("migration-test"))  # b'works'

Every Redis command I used — GET, SET, EXPIRE, HGETALL, ZRANGEBYSCORE, pub/sub — behaved identically. I ran both in parallel for a week with dual-writes; zero divergence.

Six weeks in

• Cache hit rate: unchanged (92%)
• Incidents: 0
• Bill: $20 → $0/month
• Ops effort: one docker compose up after a VM reboot, once

The one thing you give up: managed failover. If the VM dies, cache is cold until it restarts. For a cache, that's a non-event — my app falls back to the database and repopulates in ~40 seconds.

I drafted the dual-write validation script with MonkeyCode (free AI coding assistant): https://ly.cyberserval.tech/iIETXiF

What's the most embarrassing line item on your cloud bill right now — and is it actually just a hashmap?