# Confluent Cloud vs Amazon MSK

Canonical: https://inetgeek.com/compare/confluent-cloud-vs-aws-msk/

Every value below is read from Confluent Cloud's and Amazon MSK's own documentation. See https://inetgeek.com/methodology/ for how.

## At a glance

| Criterion | Confluent Cloud | Amazon MSK |
| --- | --- | --- |
| Entry paid plan | Basic gives the first eCKU free and charges $0.14 per eCKU-hour after it, so a small cluster starts near zero. Standard, the first tier with a 99.99% SLA, starts at about $385 a month. | $0.75 per cluster-hour on Serverless — about $547 a month for a cluster that has moved no data at all, before partitions, transfer or storage are counted. |
| Pricing model | Three meters running together. Compute is billed per eCKU-hour — an elastic Confluent Kafka Unit that autoscales — data in and out is billed per GB, and data at rest per GB-month. The rates are published pre-replication, so a replicated topic costs a multiple of the figure shown. | Serverless bills FIVE dimensions simultaneously: $0.75 per cluster-hour, $0.0015 per partition-hour, $0.10 per GB in, $0.05 per GB out and $0.10 per GB-month stored. Provisioned clusters swap the first two for a per-broker hourly rate. Nothing here is a single number. |
| Egress over allowance | $0.05 per GB in or out on Basic, falling to $0.014–$0.030 on Freight. Ingress and egress are charged at the same rate rather than separately. | $0.05 per GB out and $0.10 per GB in on Serverless. Ingress costs twice egress here, which is the reverse of most of this site's corpus. |
| Storage price | $0.08 per GB-month on Basic, Standard and Enterprise alike; $0.03 on Freight, which writes direct to object storage. | $0.10 per GB-month on Serverless. |
| Partition limit | No figure is published. Enterprise advertises "enhanced partition limits" over Standard without saying what either limit is, so the ceiling cannot be compared with a vendor that states one. | 2,400 partition leaders per Serverless cluster for non-compacted topics, and 120 for compacted ones. Partitions are metered as well as capped — $0.0015 per partition-hour, so 2,400 of them cost about $2.65 a day carrying no traffic. |

## Where they differ

### Entry paid plan

- Confluent Cloud: Basic gives the first eCKU free and charges $0.14 per eCKU-hour after it, so a small cluster starts near zero. Standard, the first tier with a 99.99% SLA, starts at about $385 a month. ([source](https://www.confluent.io/confluent-cloud/pricing/))
- Amazon MSK: $0.75 per cluster-hour on Serverless — about $547 a month for a cluster that has moved no data at all, before partitions, transfer or storage are counted. ([source](https://pricing.us-east-1.amazonaws.com/offers/v1.0/aws/AmazonMSK/current/us-east-1/index.json))

### Pricing model

- Confluent Cloud: Three meters running together. Compute is billed per eCKU-hour — an elastic Confluent Kafka Unit that autoscales — data in and out is billed per GB, and data at rest per GB-month. The rates are published pre-replication, so a replicated topic costs a multiple of the figure shown. ([source](https://www.confluent.io/confluent-cloud/pricing/))
- Amazon MSK: Serverless bills FIVE dimensions simultaneously: $0.75 per cluster-hour, $0.0015 per partition-hour, $0.10 per GB in, $0.05 per GB out and $0.10 per GB-month stored. Provisioned clusters swap the first two for a per-broker hourly rate. Nothing here is a single number. ([source](https://pricing.us-east-1.amazonaws.com/offers/v1.0/aws/AmazonMSK/current/us-east-1/index.json))

### Egress over allowance

- Confluent Cloud: $0.05 per GB in or out on Basic, falling to $0.014–$0.030 on Freight. Ingress and egress are charged at the same rate rather than separately. ([source](https://www.confluent.io/confluent-cloud/pricing/))
- Amazon MSK: $0.05 per GB out and $0.10 per GB in on Serverless. Ingress costs twice egress here, which is the reverse of most of this site's corpus. ([source](https://pricing.us-east-1.amazonaws.com/offers/v1.0/aws/AmazonMSK/current/us-east-1/index.json))

### Storage price

- Confluent Cloud: $0.08 per GB-month on Basic, Standard and Enterprise alike; $0.03 on Freight, which writes direct to object storage. ([source](https://www.confluent.io/confluent-cloud/pricing/))
- Amazon MSK: $0.10 per GB-month on Serverless. ([source](https://pricing.us-east-1.amazonaws.com/offers/v1.0/aws/AmazonMSK/current/us-east-1/index.json))

### Partition limit

- Confluent Cloud: No figure is published. Enterprise advertises "enhanced partition limits" over Standard without saying what either limit is, so the ceiling cannot be compared with a vendor that states one. ([source](https://www.confluent.io/confluent-cloud/pricing/))
- Amazon MSK: 2,400 partition leaders per Serverless cluster for non-compacted topics, and 120 for compacted ones. Partitions are metered as well as capped — $0.0015 per partition-hour, so 2,400 of them cost about $2.65 a day carrying no traffic. ([source](https://docs.aws.amazon.com/msk/latest/developerguide/limits.html))

## Which should you choose?

Pick Confluent Cloud if The reference implementation, and the one that shows its working. Three meters are each published with a rate, and the page states they are pre-replication — a disclosure the others skip entirely. Standard at about $385 a month is the cheapest 99.99% SLA in this category.

Pick Amazon MSK if You are already on AWS and want Kafka inside the same IAM, the same VPC and the same bill. Serverless scales partitions for you and states no maximum retention at all, which nothing else here offers.

Consider something else: Confluent Cloud — Your traffic is write-heavy and you are counting cents. Three meters compound: eCKU-hours accrue whether or not you publish, data in and out is $0.05 a gigabyte on Basic, and storage is $0.08 per gigabyte-month on every tier below Freight.

Consider something else: Amazon MSK — You want to predict the bill. Five meters run at once and the floor is $0.75 per cluster-hour — about $547 a month before a byte moves. Ingress costs twice egress, the reverse of most of this corpus, and the 2,400-partition ceiling costs about $2.65 a day carrying no traffic.

## Documented by only one

- Uptime SLA: Confluent Cloud: 99.99% on Standard and above. Basic carries no uptime commitment.
- Throughput ceiling: Amazon MSK: 200 Mbps ingress and 400 Mbps egress per Serverless cluster, throttled rather than refused. That is 25 MB/s in — a quarter of what Redpanda Serverless states, once the units are read.
- Audit logs: Confluent Cloud: Audit logs arrive on Standard, the first paid tier above Basic.
- Maximum message size: Amazon MSK: 8 MiB on Serverless. A larger message fails outright with INVALID_REQUEST rather than being throttled.
- Message retention: Amazon MSK: Unlimited. Serverless states no maximum retention duration, where WarpStream's published configuration is seven days.

## Questions this comparison answers

**Entry paid plan: Confluent Cloud or Amazon MSK?**

Confluent Cloud: Basic gives the first eCKU free and charges $0.14 per eCKU-hour after it, so a small cluster starts near zero. Standard, the first tier with a 99.99% SLA, starts at about $385 a month.
Amazon MSK: $0.75 per cluster-hour on Serverless — about $547 a month for a cluster that has moved no data at all, before partitions, transfer or storage are counted.

**Egress over allowance: Confluent Cloud or Amazon MSK?**

Confluent Cloud: $0.05 per GB in or out on Basic, falling to $0.014–$0.030 on Freight. Ingress and egress are charged at the same rate rather than separately.
Amazon MSK: $0.05 per GB out and $0.10 per GB in on Serverless. Ingress costs twice egress here, which is the reverse of most of this site's corpus.

**Should I choose Confluent Cloud or Amazon MSK?**

Pick Confluent Cloud if The reference implementation, and the one that shows its working. Three meters are each published with a rate, and the page states they are pre-replication — a disclosure the others skip entirely. Standard at about $385 a month is the cheapest 99.99% SLA in this category.
Pick Amazon MSK if You are already on AWS and want Kafka inside the same IAM, the same VPC and the same bill. Serverless scales partitions for you and states no maximum retention at all, which nothing else here offers.