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Databases · head to head

RabbitMQ vs Memcached

RabbitMQ logo

RabbitMQ

Databases

Open-source message broker supporting AMQP and other protocols

From
Free
Rated
-
Full reviewWebsite
Memcached logo

Memcached

Databases

Distributed memory object caching system

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: RabbitMQ not built for replay: once consumed, a message is gone, which is exactly what Kafka exists to change; Memcached no persistence at all: restart a node and its cache is gone, which every design must assume
  • They diverge on capability: RabbitMQ covers Flexible routing, Memcached covers In-memory key-value cache.

Where they differ

Only the attributes on which RabbitMQ and Memcached actually diverge.

Attributes where RabbitMQ and Memcached differ
AttributeRabbitMQMemcached
Pricing modelOpen source, no licence fee; managed services billed separatelyOpen source, no licence fee; managed cloud billed separately
PlatformsLinux, macOS, Windows, Docker, KubernetesLinux, macOS, Windows, Docker, Self-hosted

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Databases).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in RabbitMQ

  • Flexible routing
  • Multiple protocols
  • Management UI
  • Clustering and mirroring

Only in Memcached

  • In-memory key-value cache
  • Multithreaded
  • Client-side sharding
  • Predictable memory use

What people use each for

The jobs each tool is most often brought in to do.

RabbitMQ

  • Distributing background jobs to a pool of workers with retriesnot Memcached
  • Decoupling services that need delivery rather than a replayable historynot Memcached
  • Routing messages by pattern to different consumers from one publishernot Memcached

Memcached

  • Caching expensive database query results to cut loadnot RabbitMQ
  • Session storage where losing sessions on restart is acceptablenot RabbitMQ
  • Fronting an API whose responses are costly and change slowlynot RabbitMQ

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

RabbitMQ

  • Not built for replay: once consumed, a message is gone, which is exactly what Kafka exists to change
  • Throughput ceilings are lower than a log-based platform under very heavy streaming loads
  • Queues that build up degrade broker performance, so consumer lag is an operational problem rather than just a backlog
  • Clustering and partition behaviour has historically been a source of hard-to-diagnose problems

Memcached

  • No persistence at all: restart a node and its cache is gone, which every design must assume
  • No replication or failover, so losing a node loses that share of the cache
  • Only simple key-value, with none of the lists, sorted sets or streams Redis offers
  • Values are capped at 1MB by default, which surprises teams caching large documents

Pricing, plan by plan

RabbitMQ

Free
  • RabbitMQFree
    • Full functionality
    • Self-hosted
    • No usage limits

Memcached

Free
  • MemcachedFree
    • Full functionality
    • Self-hosted
    • No usage limits

Which should you pick?

Choose RabbitMQ if

  • You need flexible routing.
  • You want to start without paying.
  • You work on Linux, macOS, Windows, Docker, Kubernetes.
  • You also want multiple protocols.
RabbitMQ review

Choose Memcached if

  • You need in-memory key-value cache.
  • You want to start without paying.
  • You work on Linux, macOS, Windows, Docker, Self-hosted.
  • You also want multithreaded.
Memcached review

Questions people ask

Is RabbitMQ or Memcached better?
Neither clearly leads. RabbitMQ starts at Free and Memcached at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, RabbitMQ or Memcached?
RabbitMQ starts at Free and Memcached at Free.
Does RabbitMQ or Memcached run on more platforms?
RabbitMQ runs on Linux, macOS, Windows, Docker, Kubernetes. Memcached runs on Linux, macOS, Windows, Docker, Self-hosted.
Can I use RabbitMQ for free?
Both have a free tier, so you can try either at no cost before committing.
What is RabbitMQ best used for?
RabbitMQ is most often used for distributing background jobs to a pool of workers with retries, decoupling services that need delivery rather than a replayable history, routing messages by pattern to different consumers from one publisher. Of those, distributing background jobs to a pool of workers with retries and decoupling services that need delivery rather than a replayable history are not what Memcached is typically brought in for.
What can RabbitMQ do that Memcached cannot?
RabbitMQ covers Flexible routing, Multiple protocols, Management UI, Clustering and mirroring. Memcached covers In-memory key-value cache, Multithreaded, Client-side sharding, Predictable memory use.

Answered from the vendors’ own pages

RabbitMQ: Is RabbitMQ free?

Yes, open source with no licence fee. Broadcom sells commercial support.

Memcached: Is Memcached free?

Yes, open source with no licence fee.

RabbitMQ: RabbitMQ or Kafka?

RabbitMQ is a message broker: simpler to run and better at flexible routing and work queues. Kafka is a replayable event log built for very high throughput streaming, and much heavier to operate.

Memcached: Memcached or Redis?

Memcached is a pure cache: simpler, multithreaded and very predictable. Redis adds persistence, replication and rich data structures, which is why it is the default choice unless you specifically want a cache and nothing more.

RabbitMQ: Can RabbitMQ replay messages?

Not in the way Kafka can. Messages are removed once acknowledged, so rebuilding state from history is not the model.

Memcached: Does Memcached persist data?

No. Everything is in memory and lost on restart, by design.

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