AWS MSK is Amazon's own managed Kafka service, and if your whole stack is already on AWS it's an easy default to reach for — one line in the console, billed on the same account as everything else. The catch is in how it's billed and what happens the day you want to leave. Here's what MSK Serverless actually costs for one real workload, and why the per-GB pricing and the AWS-only footprint matter more than they look like upfront.
The workload
10 MiB/s of compressed data in, 20 MiB/s of compressed data out (a common 2× fan-out), 7‑day retention — roughly 6.3 TB retained at any time. The same workload we use in our Confluent Cloud and self-managed AWS comparisons.
Pricing, side by side
| ntail | AWS MSK (Serverless) | |
|---|---|---|
| Pricing model | Pay as you go, per started hourData in, data out, storage — nothing else | Cluster-hours + partition-hoursPlus separate data in, data out & storage fees |
| Cluster / partition fee | None | $0.75 per cluster-hour + $0.0015 per partition-hour≈$554/mo on this workload |
| Data in | $25 per 1 MiB/s / monthCompressed, volume discounts from 100 MiB/s | $0.10 per GB≈$2,718/mo — yes, data in is metered too |
| Data out | $25 per 1 MiB/s / monthCompressed, volume discounts from 100 MiB/s | $0.05 per GB≈$2,718/mo, any destination |
| Storage | $20 per TB / monthSingle-copy pricing | $0.10 per GB-month≈$1,890/mo, billed on ~3× post-replication volume |
| Public internet traffic | $0 — never metered | Included in the per-GB in/out rate |
| Example monthly cost10 MiB/s in · 20 MiB/s out · 7-day retention | $876 | $7,880 |
Illustrative, list-price figures. The MSK model — cluster and partition hours, per-GB data in/out, ~3× replicated storage — and ntail's own pricing are both modeled in full in our pricing calculator FAQ. Ask us for a quote modeled against your actual bill.
Egress: metered coming in, not just going out
Most managed Kafka pricing charges for data leaving the service and treats data arriving as part of the deal. MSK Serverless meters both directions separately — $0.10 per GB in, $0.05 per GB out — and that per-GB rate applies to delivery anywhere, including the public internet, with no free allowance. On this workload that's roughly $5,436 a month on data movement alone, before a single byte is stored. Every new producer, every new consumer and every analytics job reading the same topics adds directly to that line. ntail's public internet traffic is $0, at any volume, so it isn't a line at all.
Lock-in: the cost of leaving
MSK only runs on AWS. The cluster is wired into your VPC, security groups and IAM the same way every other AWS service is, which is convenient right up until you want to run Kafka somewhere else — a different cloud, a different region for cost or compliance reasons, or your own infrastructure. At that point you're paying MSK's own per-GB data-out rate to read everything back out, on top of whatever it costs to move that data off AWS entirely. The more data you've accumulated — and MSK has no cap on retention — the more that one-time exit costs. It's rarely the sticker price that keeps a team on a platform; it's the bill for leaving it.
ntail has no proprietary client to adopt and no egress toll on the way out. Export everything you've stored whenever you want, and pay nothing for the transfer.
A European company, on our own European infrastructure
ntail is operated by Factual Tech AB, a company registered in Sweden. Customer data is processed and stored in the EU by default — other regions, including the US, available on request — on infrastructure we operate ourselves, not a single hyperscaler's region map. For teams with stricter residency or sovereignty requirements, we can also run a dedicated cluster fully off the public cloud, in a specific region of your choice. See how we handle security for the full detail.
Which one is right for you
If you're fully committed to AWS and the per-GB fees aren't showing up as a problem yet, MSK is a reasonable default. But if data in and data out are turning into the biggest, fastest-growing line on your bill — or you want the option to leave without paying for the privilege — it's worth modeling your own workload against ntail's pricing, or seeing how ntail compares to the other managed streaming options.