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Comparison · Infra & APIs

Fission vs Nebula

A side-by-side editorial comparison of Fission and Nebula — release velocity, themes, recent moves, and the top alternatives to consider.

Fission vs Nebula: at a glance

FeatureFissionNebula
SectorInfra & APIsInfra & APIs
Velocity score0.02.5
Sparks · 30d00
Top themesserverless, kubernetes, faas, release-candidatesmesh-vpn, overlay-network, certificates, ipv6
Last editorial update2h ago3h ago
WebsiteVisit →Visit →

What is Fission?

Fission's release feed carries only RC tags, and none of them say what shipped

Every entry here is a release candidate — v1.22.0-rc1 and rc2, v1.23.0-rc1, v1.25.0-rc1 — with no final release appearing between them, and the version sequence skips 1.24 entirely. The bodies are whatever the tagging commit said, so what reaches this feed is a dependabot bump, a CLI tool-version refresh, a codegen sync explicitly labelled as having no functional change, and one entry that is nothing but links to an external release-highlights page. The actual release notes live on the project's documentation site, not here.

Read the full Fission trajectory →

What is Nebula?

Overlay network that rewrote its certificate format, then spent a year fixing what it exposed.

Nebula is a peer-to-peer mesh VPN built around a certificate authority model. The v1.10.0 release was the pivot: IPv6 and multiple addresses in the overlay, plus a new v2 ASN.1 certificate format with a unified interface for external implementations. Everything since has been consequence management — a P256 signature malleability issue that allowed blocklist bypass, a source-IP acceptance flaw tied to the new multi-address certificates, and a run of fixes around route tables and Windows listeners.

Read the full Nebula trajectory →

Fission vs Nebula: editorial side-by-side

F
Fission
INFRA · APIS
0.0

Fission's release feed carries only RC tags, and none of them say what shipped

◆ Current state

Every entry here is a release candidate — v1.22.0-rc1 and rc2, v1.23.0-rc1, v1.25.0-rc1 — with no final release appearing between them, and the version sequence skips 1.24 entirely. The bodies are whatever the tagging commit said, so what reaches this feed is a dependabot bump, a CLI tool-version refresh, a codegen sync explicitly labelled as having no functional change, and one entry that is nothing but links to an external release-highlights page. The actual release notes live on the project's documentation site, not here.

◆ Where it's heading

What can be read from these tags is infrastructure maintenance rather than product direction: Go dependency updates, helm and kind and skaffold and cosign version refreshes, and regenerated swagger and applyconfiguration files kept in sync with CEL and webhook validation comments in the core API types. That last one is the only entry hinting at anything structural — CEL-based validation on the API types implies declarative validation moving into the CRDs — but the commit itself changes only generated output.

◆ Prediction

This feed does not carry enough to predict product direction; until final releases or their notes appear here rather than only candidate tags, any read of where Fission is heading would be guesswork.

N
Nebula
INFRA · APIS
2.5

Overlay network that rewrote its certificate format, then spent a year fixing what it exposed.

◆ Current state

Nebula is a peer-to-peer mesh VPN built around a certificate authority model. The v1.10.0 release was the pivot: IPv6 and multiple addresses in the overlay, plus a new v2 ASN.1 certificate format with a unified interface for external implementations. Everything since has been consequence management — a P256 signature malleability issue that allowed blocklist bypass, a source-IP acceptance flaw tied to the new multi-address certificates, and a run of fixes around route tables and Windows listeners.

◆ Where it's heading

The project has moved from single-IPv4-per-node assumptions toward a genuinely flexible addressing model, and the security fixes since v1.10.0 map directly onto that change — the new certificate features widened what the code has to validate. v1.11.0 shifts attention to the operational surface instead: structured logging, corrected firewall reject-versus-drop semantics, and Windows WFP filters installed by default.

◆ Prediction

The stated plan to assert low-s signature form when validating certificates is the concrete next step visible in these entries; expect it to land as a breaking validation change in a future release.

Alternatives to Fission and Nebula

Other Infra & APIs products tracked by Sparkpulse, ranked by recent ship velocity. Each card links to a full editorial trajectory and lets you pivot into a head-to-head comparison with either Fission or Nebula.

See all Fission alternatives → · See all Nebula alternatives →

Recent activity from Fission and Nebula

Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.

  1. 18d agoNebulaBreaking: slog logging, corrected firewall reject/drop directions, Windows WFP filters
  2. 2mo agoFissionFission 1.25.0-rc1 tag carries only regenerated codegen output
  3. 2mo agoFissionFission 1.23.0-rc1 tag carries a CI tool-version refresh
  4. 6mo agoNebulaP256 signature malleability allowed blocklist bypass
  5. 6mo agoNebulaFix panic in use_system_route_table introduced by the previous release
  6. 6mo agoNebulaRoute-reload, handshake, and Windows listener fixes after the v1.10 rework
  7. 7mo agoFissionv1.22.0-rc2
  8. 8mo agoNebulaIPv6 and multiple addresses in the overlay, plus a v2 certificate format
  9. 9mo agoFissionFission 1.22.0-rc1 tag carries a golang.org/x/net bump
  10. 10mo agoNebulaPackets accepted from erroneous source IPs with unsafe_routes or multi-IP certificates

Frequently asked questions

What is the difference between Fission and Nebula?

They serve adjacent needs but don't currently overlap on shipped themes. Nebula is currently shipping more aggressively (velocity 2.5 vs 0.0), with 0 editorial sparks in the last 30 days against 0. See the at-a-glance table above for a side-by-side breakdown of velocity, recent sparks, and editorial themes.

Is Fission better than Nebula?

Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. Nebula is currently shipping more aggressively (velocity 2.5 vs 0.0), with 0 editorial sparks in the last 30 days against 0. For your specific use case, the alternatives sections above list other Infra & APIs products to evaluate alongside.

What are the best alternatives to Fission?

Top Fission alternatives in Infra & APIs are ranked by recent ship velocity. Browse the "Fission alternatives" section above for the current picks, or visit /alternatives/fission for the full list with editorial commentary on each.

What are the best alternatives to Nebula?

Top Nebula alternatives in Infra & APIs are ranked by recent ship velocity. Browse the "Nebula alternatives" section above for the current picks, or visit /alternatives/nebula-networking for the full list with editorial commentary on each.