Confluent Cloud vs Redpanda Cloud vs AWS MSK Serverless: Real Kafka Cost per 1 Billion Messages in 2026
The short answer: none of the three bills "a message". Each bills cluster time (or a capacity unit), the gigabytes written and read, and the gigabytes retained, so the cost of 1 billion messages depends almost entirely on how large each message is and how many consumers read it. At an illustrative 1 KiB per message, two consumer groups and 7-day retention, 1 billion messages cost about $161 on Confluent Cloud Basic, $665–$708 on Confluent Standard, about $267 on Redpanda Serverless and about $815 on AWS MSK Serverless. At 10 KiB per message the same one billion messages cost about $1,609, $1,727–$2,156, $1,520 and $2,732 respectively. The gap between platforms is dominated by fixed hourly charges at small message sizes and by per-gigabyte ingress and egress rates at large ones, so the cheapest platform at 1 KiB is not necessarily the cheapest at 10 KiB. Confluent is also now an IBM company (the $11 billion acquisition closed March 17, 2026), which does not change the published rate card but is relevant to contract terms and renewal pricing.
The billing-unit mismatch, up front
Confluent Cloud bills Elastic Confluent Units for Kafka (eCKUs) per hour for cluster capacity, ingress and egress per GB, and storage per GB-month, with connectors, Flink and governance billed separately. Redpanda Serverless bills a base hourly charge, ingress and egress per GB, a per-partition-hour charge, and storage. MSK Serverless bills a per-cluster hour, a per-partition hour, ingress and egress per GB, and storage per GB-month. Confluent measures throughput and storage in binary gigabytes (1 GB = 2^30 bytes); this article treats all three vendors' "GB" as GiB. A message is not a billing unit anywhere, so the normalization must convert 1 billion messages into gigabytes written, gigabytes read, partitions, and gigabytes retained.
What each vendor actually bills
Confluent Cloud (OFFICIAL, confluent.io/pricing). Basic: first eCKU free, then $0.14 per eCKU-hour; $0.05/GB ingress and egress; $0.08/GB-month storage; 99.5% SLA, 5 TB storage cap, public endpoints. Standard: $0.75 per eCKU-hour; $0.035–$0.050/GB ingress and egress (the rate falls with usage); $0.08/GB-month; 99.9% SLA on 1 eCKU, 99.99% on 2 or more; infinite storage. Enterprise: $1.75–$2.25 per eCKU-hour; $0.020–$0.050/GB; private networking only; 1,920 MBps ingress ceiling and 96,000 partitions. Freight (a specialty cluster for relaxed-latency logging workloads): $2.25 per eCKU-hour with a 2-eCKU minimum, $0.014–$0.030/GB, $0.03/GB-month storage; not modeled here. Confluent's own "estimated starting cost" figures ($385 Standard, $895 Enterprise) correspond to about 510 billed hours of one eCKU, not a full 730-hour month; this article bills the full month. A separate partition-hour charge applied under legacy Basic and Standard billing, and the current published rate card shows no partition line. Connectors (per GB plus per task-hour), Flink (per CFU-minute) and Schema Registry (per environment-hour) are additional. Volume-based discounts and annual commitments are negotiated.
Redpanda Serverless (REPORTED; figures from Redpanda's published launch rate card, with current public pricing less granular than its competitors'). $0.10 per hour base; $0.045/GB ingress; $0.04/GB egress; $0.0015 per partition-hour; storage about $0.09/GB-month ($0.00012329 per GB-hour); limits of 100 MiBps ingress and 300 MiBps egress and 5,000 partitions per cluster. Redpanda Dedicated and Bring Your Own Cloud (data plane in the customer's own account, with cloud-provider transfer and compute billed separately) do not publish a public rate and are QUOTE-ONLY.
AWS MSK Serverless (OFFICIAL, aws.amazon.com/msk/pricing, us-east-1). $0.75 per cluster-hour; $0.0015 per partition-hour; $0.10/GB for data produced (in); $0.05/GB for data consumed (out, including replication); $0.10/GB-month storage. MSK Provisioned (about $0.21 per broker-hour at the small end) and MSK Express brokers are separate products with broker-based pricing and are not modeled. Standard AWS data-transfer rates apply separately for traffic to another region or out to the public internet, on top of the GB-in/GB-out rates above. MSK Serverless caps aggregate cluster throughput at roughly 200 MB/s in, with a per-partition ceiling around 5 MB/s in.
Normalizing the workload
All ILLUSTRATIVE. 1 billion messages a month; two message-size scenarios, 1 KiB and 10 KiB; 50 partitions; 7-day retention at steady state; two consumer groups, so egress is twice ingress; one production cluster, public endpoints. That yields 953.67 GiB ingress and 1,907.35 GiB egress at 1 KiB, and 9,536.74 GiB and 19,073.49 GiB at 10 KiB. Average retained data is 7/30 of a month's ingress: 222.52 GiB and 2,225.24 GiB. The average ingest rate is 0.37 MiB/s and 3.72 MiB/s, far inside every platform's limits, so one eCKU suffices on Confluent. Billing is assumed to be on message bytes as produced and read; compression ratio and batching affect what each vendor actually meters and should be confirmed. 730 hours a month; replication cost is included in each vendor's listed per-GB rates.
Cost at the normalized workload
Formulas: Confluent = eCKU-hours × rate + (ingress + egress GiB) × rate + stored GiB × $0.08; Redpanda = $0.10 × 730 + ingress × $0.045 + egress × $0.04 + 50 × $0.0015 × 730 + stored × $0.00012329 × 730; MSK = $0.75 × 730 + 50 × $0.0015 × 730 + ingress × $0.10 + egress × $0.05 + stored × $0.10.
| Platform | 1 KiB per message | 10 KiB per message |
|---|---|---|
| Confluent Basic (first eCKU free) | $160.85 | $1,608.53 |
| Redpanda Serverless | $266.99 | $1,520.12 |
| Confluent Standard (1 eCKU; $0.05 to $0.035/GB) | $708.35 to $665.44 | $2,156.03 to $1,726.88 |
| AWS MSK Serverless | $815.24 | $2,732.12 |
| Confluent Enterprise (1 eCKU at $1.75; $0.05 to $0.02/GB) | $1,438.35 to $1,352.52 | $2,886.03 to $2,027.72 |
Line items at 1 KiB: Confluent Basic is $47.68 ingress, $95.37 egress and $17.80 storage, with no cluster charge on the first eCKU; Redpanda is $73.00 base, $42.92 ingress, $76.29 egress, $54.75 partitions and $20.03 storage; MSK is $547.50 cluster, $54.75 partitions, $95.37 ingress, $95.37 egress and $22.25 storage. At 1 KiB the fixed hourly charge decides the ranking: MSK's and Confluent Standard's roughly $550 monthly cluster-hour charge is more than two-thirds of their bills, while Basic's free first eCKU makes it nearly all data charges. At 10 KiB, data charges dominate everywhere, and the lower per-GB rates at Redpanda ($0.045/$0.04) place it just below Confluent Basic.
What Basic gives up, and what Standard buys
Confluent Basic's low price is real for this workload, but the tier is a different product from the others: a 99.5% SLA, a 5 TB storage cap (the 10 KiB scenario retains 2.2 TB), public endpoints only, and limited governance and audit features. Standard adds a 99.9% to 99.99% SLA, unlimited storage and audit logs, and is the first tier priced like a production cluster. Redpanda Serverless and MSK Serverless both advertise 99.9% SLAs, so the Basic-versus-Standard price gap should be read as the price of a higher SLA tier, not as a pure vendor difference.
Sensitivity
- Message size. Moving from 1 KiB to 10 KiB multiplies data-dependent charges tenfold. Confluent Basic rises about tenfold ($161 to $1,609), while MSK Serverless rises about 3.4 times ($815 to $2,732) because its cluster-hour fee is a smaller part of the larger bill.
- Consumer fan-out. Each added consumer group adds a full egress copy: at 10 KiB, a third group adds $476.84 on Confluent Basic and on MSK, and $381.47 on Redpanda.
- Retention. Storage is a small share at 7 days, but 30-day retention at 10 KiB raises stored data from 2.2 TB to 9.5 TB, adding about $585 a month on Confluent and $731 on MSK at their storage rates.
- Cluster tier and networking. Enterprise's private networking and higher limits cost about $730 more a month in eCKU charges than Standard at the list rate, before PrivateLink and cross-AZ transfer.
Budgeting traps
- Estimating from message count. None of the three bills it; a 10x larger message is a roughly 10x larger data bill.
- Using Confluent's "estimated starting cost" as a monthly price. It corresponds to about 510 eCKU-hours, not a full month of continuous capacity.
- Comparing Basic to MSK Serverless as like for like. Basic has a lower SLA, a storage cap and no private networking.
- Forgetting everything outside the cluster. Connectors, Flink, Schema Registry, cross-AZ and cross-region transfer, and private connectivity are billed separately on every platform.
- Assuming an acquisition left contracts untouched. Confluent's rate card is published, but negotiated discount tables and annual commitments are the part IBM ownership may change.
What to ask before you buy
Ask each vendor what byte count it actually meters (compressed or uncompressed, and whether replication or batching headers count), and what discount your expected annual volume earns. Ask Confluent for the volume-discount tables and IBM's packaging plans before a multi-year commitment, confirm Redpanda's current Serverless rate card and whether Dedicated or BYOC suits your volume, and check AWS's current MSK Serverless limits for partitions and throughput.