SeaweedFS vs Backblaze B2
Both are alternatives to Amazon S3. Here's how they stack up — verified facts, no spin.
Also searched as Backblaze B2 vs SeaweedFS — same comparison, one verdict.
SeaweedFS is open source (Apache-2.0) and Backblaze B2 is not (Proprietary (hosted service)) — so the real question is whether you want to own the object storage stack or rent it.
SeaweedFS
Built for billions of small files, where most object stores struggle.
SeaweedFS is a distributed file and object store designed around a specific weakness in the others: enormous numbers of small files. Its architecture keeps metadata lookups fast where conventional object stores slow down, which makes it a strong fit for image, thumbnail and document workloads at scale. Apache-2.0, around 34k stars, with an S3-compatible gateway and tiered storage to cloud back-ends. It is less known than MinIO and that is the main caution — fewer worked examples when something goes wrong.
Backblaze B2
A quarter of S3's storage price, with free egress to partner networks.
B2 is about $0.006 per GB per month — roughly a quarter of S3 Standard — with free egress to Cloudflare and other Bandwidth Alliance partners and generous free egress otherwise. It is S3-API compatible and the company has published its storage-durability statistics for years, which is a level of transparency the hyperscalers do not match. For backups and archives specifically it is very hard to beat on price. It is proprietary and hosted, and the ecosystem around it is small compared with AWS.
Side by side
10 points of comparison, every one read from a verified field. Green marks the side that wins a row outright. A dash means we do not hold that fact — never that it is zero.
| SeaweedFS | Backblaze B2 | |
|---|---|---|
| Sovereignty ScoreOur transparent 0–100 composite for data ownership and exit cost. | 93 | 42 |
| Open source | Yes | No |
| Self-hostable | Yes | No |
| Local-first data | Yes | No |
| License | Apache-2.0 | Proprietary (hosted service) |
| Pricing | Free and open source. You supply the hardware. | About $0.006/GB/month storage; free egress to Bandwidth Alliance partners. Checked 2026-08-04. |
| RAM to run it wellThe figure that actually matters, not the vendor's minimum. | 4 GB across master and volume servers | — |
| Realistic running costWhat the box costs each month if you run it yourself. | $20–50/mo for a few TB, against S3 pricing that is cheaper per GB but charges per request and per byte out | — |
| Setup timeHonest first-install estimate, not the marketing quickstart. | Half a day | — |
| Ongoing maintenanceThe part nobody budgets for. | Moderate. Volume management and replication settings are yours. | — |
SeaweedFS edges it on the Sovereignty Score, but the right pick depends on the trade-offs below.
SeaweedFS
Strengths
- +Handles billions of small files where other object stores degrade
- +Apache-2.0 — more permissive than MinIO's AGPL
- +S3-compatible gateway plus a real filesystem interface
- +Tiered storage to cloud back-ends for cold data
Trade-offs
- −Smaller community and fewer worked examples than MinIO
- −More moving parts — master, volume and filer servers
- −Documentation is thinner
- −Less battle-tested at enterprise scale
Backblaze B2
Strengths
- +Roughly a quarter of S3's storage price
- +Free egress to Cloudflare and other partner networks
- +S3-compatible API
- +Publishes real durability and drive-failure statistics
Trade-offs
- −Proprietary and hosted
- −Far smaller service ecosystem than AWS
- −Fewer regions, which matters for latency and residency
- −Not built for high-throughput analytics workloads
Which one fits you
The trade-offs above, turned into a decision. Find the line that describes your team.
Choose SeaweedFS
if you want the source and the option to fork it, and you would rather run it on your own hardware, and your data should stay on machines you control.
Choose Backblaze B2
if roughly a quarter of S3's storage price.
Neither, yet
if both carry a real cost you should weigh first — smaller community and fewer worked examples than MinIO, and proprietary and hosted. If either of those is a dealbreaker for your team, the shortlist is wrong rather than the choice.
What it takes to run these yourself
Real requirements and honest running costs, not the vendor quickstart.
SeaweedFS vs Backblaze B2 — common questions
Is SeaweedFS a better fit than Backblaze B2 for object storage?
It depends on what you are optimising for, and the honest split is this: SeaweedFS scores 93 to Backblaze B2's 42 on data ownership and exit cost, so it is the safer choice if you care about being able to leave. Backblaze B2 earns its place on a different axis — roughly a quarter of S3's storage price. Neither is a wrong answer for every team; the table above is the actual comparison.
What happens if we want to switch later?
SeaweedFS keeps its data local or in open formats, so leaving is an export rather than a negotiation. Backblaze B2 keeps your data on its own infrastructure, which is the part to plan for: confirm the export path before you commit, not when you are already trying to leave.
Can I self-host SeaweedFS?
SeaweedFS can be self-hosted; Backblaze B2 cannot, so it stays on the vendor's infrastructure whatever you do.
Are SeaweedFS and Backblaze B2 both alternatives to Amazon S3?
Yes — both appear in our Amazon S3 comparison, which is why they are worth putting side by side. People usually arrive here already having decided to move off Amazon S3 and now choosing between the two replacements, which is a narrower and much easier question.
Related alternative guides
Facts verified 2026-08-04. Licenses and pricing change — spotted something out of date? That's a correction we want.