q2
Ten releases in six days, methodically porting Quarto's surface into a Rust binary.
Comparison · Infra & APIs
carrier vs rush
A side-by-side editorial comparison of carrier and rush — release velocity, themes, recent moves, and the top alternatives to consider.
carrier vs rush: at a glance
What is carrier?
carrier's 0.3.0 quietly rewrites how crated functions see each other — and breaks code that relied on the old rules.
carrier packages an R function together with the data it needs so it can be shipped to another process or machine. 0.3.0 changed the semantics of functions passed through ...: they are now re-crated inside the main crate environment instead of inheriting from wherever they were defined. That fixes helper functions failing to resolve each other remotely, and stops local environments dragging large objects into the payload.
What is rush?
Rush spent 2026 making distributed task ownership correct, starting with a breaking 1.0.
rush is the Redis-backed distributed computing backend behind mlr3's parallel tuning: workers pull tasks, push results and are tracked through heartbeats. Since 1.0.0 in March 2026 it has shipped five releases in four months, almost all correcting how tasks and workers are owned and identified under failure. The most recent lets each worker start in its own mirai call so it can spawn local daemons.
carrier vs rush: editorial side-by-side
carrier
0.0INFRA · APIS
carrier's 0.3.0 quietly rewrites how crated functions see each other — and breaks code that relied on the old rules.
◆ Current state
carrier packages an R function together with the data it needs so it can be shipped to another process or machine. 0.3.0 changed the semantics of functions passed through ...: they are now re-crated inside the main crate environment instead of inheriting from wherever they were defined. That fixes helper functions failing to resolve each other remotely, and stops local environments dragging large objects into the payload.
◆ Where it's heading
Each release tightens the boundary between a crate and its surroundings. 0.2.0 introduced .parent_env defaulting to baseenv() to cut the crate off from the global search path and made unnamed ... arguments an error instead of a silent drop; 0.3.0 finishes the job by controlling the environment chain of the packed closures themselves. The package is trading backwards compatibility for predictable, self-contained payloads — a reasonable bet for something whose failures otherwise surface on a remote worker.
◆ Prediction
The 0.1.0 notes promised an automatic dependency-detection mode to replace explicit packing; nothing since has delivered it, and with the environment semantics now settled that is the obvious next move — though the entries give no date for it.
rush
2.5INFRA · APIS
Rush spent 2026 making distributed task ownership correct, starting with a breaking 1.0.
◆ Current state
rush is the Redis-backed distributed computing backend behind mlr3's parallel tuning: workers pull tasks, push results and are tracked through heartbeats. Since 1.0.0 in March 2026 it has shipped five releases in four months, almost all correcting how tasks and workers are owned and identified under failure. The most recent lets each worker start in its own mirai call so it can spawn local daemons.
◆ Where it's heading
The through-line is moving responsibility from the controller to the worker. 1.0.0 rewrote the task lifecycle and dropped the seed mechanism; 1.2.0 moved fail_tasks(), finish_tasks(), pop_task() and push_running_tasks() from Rush onto RushWorker so only the worker that ran a task can mark it done, and gave worker ids random suffixes so they cannot collide. 1.1.0 had already removed phantom failed tasks when a worker crashes between evaluations.
◆ Prediction
With ownership and identity settled, the remaining pressure points are heartbeat and lost-worker detection; expect the next releases to tighten failure recovery rather than add API surface.
Alternatives to carrier and rush
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 carrier or rush.
pkgcache
The metadata cache under pak now speaks to authenticated and corporate repositories.
packrat
R's old dependency manager now runs on a vendored copy of its own successor.
webfakes
A fake web server for tests that keeps closing the gap with the real thing.
pool
Hit 1.0, relicensed to MIT, and has shipped almost nothing but dbplyr compatibility since.
evaluate
The engine under every knitted R document reached 1.0 by making evaluation behave like the console.
See all carrier alternatives → · See all rush alternatives →
Recent activity from carrier and rush
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 21d agorushWorkers start in their own mirai call so they can create local daemons
- 1mo agorushTask lifecycle moves onto the worker; worker ids can no longer collide
- 3mo agorushPhantom failed tasks and missed results fixed
- 4mo agorushSmaller Redis payloads and vector-valued task parameters
- 4mo agorushRush 1.0 rewrites the task lifecycle and drops the seed mechanism ⚡
- 9mo agorushwait_for_workers() can target a count or specific ids
- 11mo agocarrierCrated helper functions can now see each other ⚡
- 1y agocarriercrate() gains .parent_env and stricter argument handling
- 3y agocarrierSource references dropped from crated functions
- 4y agocarrierInitial release with explicit-only crate packing
Frequently asked questions
What is the difference between carrier and rush?
They serve adjacent needs but don't currently overlap on shipped themes. rush 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 carrier better than rush?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. rush 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 carrier?
Top carrier alternatives in Infra & APIs are ranked by recent ship velocity. Browse the "carrier alternatives" section above for the current picks, or visit /alternatives/carrier for the full list with editorial commentary on each.
What are the best alternatives to rush?
Top rush alternatives in Infra & APIs are ranked by recent ship velocity. Browse the "rush alternatives" section above for the current picks, or visit /alternatives/rush for the full list with editorial commentary on each.