GravityKit
GravityKit ships weekly across a whole plugin suite, with an MCP server now part of the lineup.
Comparison · Infra & APIs
Firecracker vs Heroku
A side-by-side editorial comparison of Firecracker and Heroku — release velocity, themes, recent moves, and the top alternatives to consider.
Firecracker vs Heroku: at a glance
What is Firecracker?
Firecracker's microVMs can now grow and shrink devices while running.
1.16.0 in June added developer-preview hotplug and hot-unplug for PCI virtio block, pmem and net devices on a live microVM, with the guest responsible for rescanning the bus and removing the device first since no notification mechanism exists yet. The same release added vsock Unix socket path overriding on snapshot restore, rate limiting for serial console output with a dropped-bytes metric, and per-callsite log rate limiting. 1.16.1 followed with a vsock fix for connections timing out after restore when a snapshot caught an in-flight TX descriptor. Earlier in the window, 1.15.0 added the VMClock device and Intel Granite Rapids support, and the April patches hardened the PCI transport against CVE-2026-5747.
What is Heroku?
Runtime bumps fill the changelog; the managed Postgres line is where Heroku actually moves.
Day to day, Heroku's changelog is language-runtime upkeep: Python, Node, Ruby, Go, PHP, JRuby and .NET point releases, buildpack refreshes for Pipenv and uv, and periodic rebuilds of the Heroku-22, Heroku-24 and Heroku-26 stacks now maintained in parallel. The exception is the managed database. Postgres 18 entered beta on 14 July and reached general availability on 4 August, and Heroku deprecated Postgres 15 on the same day.
Firecracker vs Heroku: editorial side-by-side
Firecracker
0.0INFRA · APIS
Firecracker's microVMs can now grow and shrink devices while running.
◆ Current state
1.16.0 in June added developer-preview hotplug and hot-unplug for PCI virtio block, pmem and net devices on a live microVM, with the guest responsible for rescanning the bus and removing the device first since no notification mechanism exists yet. The same release added vsock Unix socket path overriding on snapshot restore, rate limiting for serial console output with a dropped-bytes metric, and per-callsite log rate limiting. 1.16.1 followed with a vsock fix for connections timing out after restore when a snapshot caught an in-flight TX descriptor. Earlier in the window, 1.15.0 added the VMClock device and Intel Granite Rapids support, and the April patches hardened the PCI transport against CVE-2026-5747.
◆ Where it's heading
The through-line is snapshots and the PCI transport maturing together. Firecracker's value has always been fast boot from a snapshot, and the recent fixes are all in the seams that opens up — TX descriptors in flight when a snapshot is taken, vsock paths that change on restore, virtio device state machines that must be validated the same way on PCI as on MMIO. Hotplug extends the same idea from restore-time to run-time: a microVM that can change shape is one you can keep rather than replace.
◆ Prediction
Hotplug shipped explicitly as a developer preview requiring manual guest bus rescans, so the stated gap is an automatic notification mechanism. That is the obvious next step before the feature leaves preview.
Heroku
5.0DEVOPSINFRA · APIS
Runtime bumps fill the changelog; the managed Postgres line is where Heroku actually moves.
◆ Current state
Day to day, Heroku's changelog is language-runtime upkeep: Python, Node, Ruby, Go, PHP, JRuby and .NET point releases, buildpack refreshes for Pipenv and uv, and periodic rebuilds of the Heroku-22, Heroku-24 and Heroku-26 stacks now maintained in parallel. The exception is the managed database. Postgres 18 entered beta on 14 July and reached general availability on 4 August, and Heroku deprecated Postgres 15 on the same day.
◆ Where it's heading
The platform is running two clocks at once. One is a near-daily maintenance cadence that keeps supported runtimes current and rarely changes behaviour. The other is a deliberate, publicly staged lifecycle for the data services, where a major version is walked from beta to GA and the version three releases behind is retired in the same announcement. Kafka is on the same track, with 2.8 and 3.7 deprecations and a revised version-support policy posted in late July.
◆ Prediction
Given that Postgres 15's deprecation was announced alongside 18's general availability, the next concrete step is a published end-of-life date and forced-upgrade window for Postgres 15. The runtime bumps will continue at their current weekly rhythm.
Firecracker alternatives
Other Infra & APIs products tracked by Sparkpulse, ranked by recent ship velocity. Tap any card for the full editorial trajectory or compare directly with Firecracker.
LibreSpeed
After a two-year redesign, LibreSpeed is adding tests instead of polishing pixels.
Nautobot
A security advisory cycle forced Nautobot to break its REST API on both supported branches at once.
Gatekeeper
Gatekeeper grew a package manager for policies — and a benchmark to prove they are not too slow.
GoCD
GoCD's changelog is one maintainer keeping a 2010s CI server running on current runtimes.
Incus
Incus settled its 7.0 LTS, then went straight back to a monthly feature cadence.
Heroku alternatives
Other Infra & APIs products tracked by Sparkpulse, ranked by recent ship velocity. Tap any card for the full editorial trajectory or compare directly with Heroku.
immudb
immudb made itself speak Postgres — while its announced v2 rearchitecture sits unfinished.
Sonic
Sonic is shipping tokenizer control and a dependency diet, two tags at a time.
Postgres Operator
Zalando's Postgres Operator finally shipped v2 — and had to reissue it within a day.
NebulaGraph
A graph database spending its releases on query-language parity and traversal speed.
Manticore Search
Manticore tags a GitHub release per commit, so the real news is one entry in five.
pgBackRest
PostgreSQL 19 support lands, and pgBackRest stops letting you run most commands as root.
Recent activity from Firecracker and Heroku
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 1d agoHerokuPostgres 18 GA and Postgres 15 deprecation; Python 3.14.7 and 3.13.15
- 23d agoHeroku.NET SDK updates across the 8.0, 9.0 and 10.0 lines
- 24d agoHerokuPostgres 18 enters beta; sbt 2 supported for Scala apps
- 25d agoHerokuHeroku-22, Heroku-24 and Heroku-26 stacks updated
- 28d agoHerokuPython buildpacks updated to Pipenv 2026.6.2 and uv 0.11.28
- 29d agoHerokuNode.js 26.5.0 now available
- 1mo agoFirecrackerVsock timeout after snapshot restore, and jailer symlink revert
- 2mo agoFirecrackerFirecracker v1.16.0 ⚡
- 4mo agoFirecrackervirtio-rng entropy cap and PCI transport hardening (CVE-2026-5747)
- 4mo agoFirecrackerCVE-2026-5747 hardening on the 1.15 branch
- 4mo agoFirecrackerTCP SYN options length validation with MMDS enabled
- 5mo agoFirecrackerVMClock device and Intel Granite Rapids support
Frequently asked questions
What is the difference between Firecracker and Heroku?
They serve adjacent needs but don't currently overlap on shipped themes. Heroku is currently shipping more aggressively (velocity 5.0 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 Firecracker better than Heroku?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. Heroku is currently shipping more aggressively (velocity 5.0 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 Firecracker?
Top Firecracker alternatives in Infra & APIs are ranked by recent ship velocity. Browse the "Firecracker alternatives" section above for the current picks, or visit /alternatives/firecracker for the full list with editorial commentary on each.
What are the best alternatives to Heroku?
Top Heroku alternatives in Infra & APIs are ranked by recent ship velocity. Browse the "Heroku alternatives" section above for the current picks, or visit /alternatives/heroku for the full list with editorial commentary on each.