# Amazon MSK vs WarpStream

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

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

## At a glance

| Criterion | Amazon MSK | WarpStream |
| --- | --- | --- |
| Entry paid plan | $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. | $100 a month for the Dev tier, which carries NO uptime SLA, before any per-gibibyte write charge. The first tier with an SLA is Fundamentals at $500. |
| Pricing model | 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. | Two lines, not one. A cluster-tier fee — $100 a month for Dev, $500 for Fundamentals, $1,500 for Pro — plus write throughput metered per gibibyte: $0.01/GiB to 50 TiB, falling to $0.003 beyond 6,250 TiB. Reads, partitions and storage are not billed; data sits in your own object storage. |
| Storage price | $0.10 per GB-month on Serverless. | Not charged separately. Data is persisted directly to your own object storage, so durability is the object store's bill rather than WarpStream's. |
| Message retention | Unlimited. Serverless states no maximum retention duration, where WarpStream's published configuration is seven days. | 7 days on the configuration the pricing calculator shows. |
| Throughput ceiling | 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. | The calculator runs from 1 MiB/s to 5 GiB/s of uncompressed write throughput, and the rate falls as the tier rises rather than the ceiling being fixed. |
| Partition limit | 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. | 4,096 on Dev, 16,384 on Fundamentals, 50,000 on Pro and 200,000+ on Enterprise. Partitions are capped by tier and not billed. |

## Where they differ

### Entry paid plan

- 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))
- WarpStream: $100 a month for the Dev tier, which carries NO uptime SLA, before any per-gibibyte write charge. The first tier with an SLA is Fundamentals at $500. ([source](https://www.warpstream.com/pricing))

### Pricing model

- 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))
- WarpStream: Two lines, not one. A cluster-tier fee — $100 a month for Dev, $500 for Fundamentals, $1,500 for Pro — plus write throughput metered per gibibyte: $0.01/GiB to 50 TiB, falling to $0.003 beyond 6,250 TiB. Reads, partitions and storage are not billed; data sits in your own object storage. ([source](https://www.warpstream.com/pricing))

### Storage price

- 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))
- WarpStream: Not charged separately. Data is persisted directly to your own object storage, so durability is the object store's bill rather than WarpStream's. ([source](https://www.warpstream.com/pricing))

### 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. ([source](https://docs.aws.amazon.com/msk/latest/developerguide/limits.html))
- WarpStream: The calculator runs from 1 MiB/s to 5 GiB/s of uncompressed write throughput, and the rate falls as the tier rises rather than the ceiling being fixed. ([source](https://www.warpstream.com/pricing))

### Partition limit

- 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))
- WarpStream: 4,096 on Dev, 16,384 on Fundamentals, 50,000 on Pro and 200,000+ on Enterprise. Partitions are capped by tier and not billed. ([source](https://www.warpstream.com/pricing))

### Message retention

- Amazon MSK: Unlimited. Serverless states no maximum retention duration, where WarpStream's published configuration is seven days. ([source](https://docs.aws.amazon.com/msk/latest/developerguide/limits.html))
- WarpStream: 7 days on the configuration the pricing calculator shows. ([source](https://www.warpstream.com/pricing))

## Which should you choose?

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.

Pick WarpStream if Write-heavy workloads where inter-zone replication is the bill. Data is acknowledged straight into your own object storage, so partitions, reads and storage are not metered at all and only gigabytes written are — $0.01 falling to $0.003 at volume.

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.

Consider something else: WarpStream — You need an availability commitment at the entry price. The $100 Dev tier carries no uptime SLA whatsoever; the first one is Fundamentals at $500, five times the floor. Lower latency is a Pro-tier feature, which is the honest cost of the object-storage design.

## Documented by only one

- Kind of free offer: WarpStream: Free credit
- Credit card to start: WarpStream: No
- Egress over allowance: 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.
- Uptime SLA: WarpStream: None at all on the $100 Dev tier. 99.9% on Fundamentals, 99.99% on Pro, and 99.999% on Enterprise only with multi-region clusters — 99.99% without.
- Maximum message size: Amazon MSK: 8 MiB on Serverless. A larger message fails outright with INVALID_REQUEST rather than being throttled.

## Questions this comparison answers

**Entry paid plan: Amazon MSK or WarpStream?**

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.
WarpStream: $100 a month for the Dev tier, which carries NO uptime SLA, before any per-gibibyte write charge. The first tier with an SLA is Fundamentals at $500.

**Should I choose Amazon MSK or WarpStream?**

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.
Pick WarpStream if Write-heavy workloads where inter-zone replication is the bill. Data is acknowledged straight into your own object storage, so partitions, reads and storage are not metered at all and only gigabytes written are — $0.01 falling to $0.003 at volume.