httpuv
httpuv ships almost nothing, which is what you want from the web server under Shiny
Comparison · DevOps
processx vs promises
A side-by-side editorial comparison of processx and promises — release velocity, themes, recent moves, and the top alternatives to consider.
processx vs promises: at a glance
What is processx?
processx adds kernel-level process pipelines after years of defensive fixes.
processx is the low-level subprocess engine underneath callr and much of the r-lib tooling stack. For several releases it shipped only hardening work: RNG hygiene, safer format strings, signal handling around terminated parents. Version 3.9.0 breaks that pattern with an experimental pipeline class.
What is promises?
promises drops R6 for plain environments and wires async work into OpenTelemetry
promises supplies the async primitives behind Shiny and plumber. After years of small domain and future() fixes, the last two releases changed both what a promise costs and what it can report: 1.4.0 corrected nested domain ordering and added the first OpenTelemetry integration, and 1.5.0 replaced the R6 promise class with a classed environment while stabilizing the tracing API.
processx vs promises: editorial side-by-side
processx
0.0DEVOPS
processx adds kernel-level process pipelines after years of defensive fixes.
◆ Current state
processx is the low-level subprocess engine underneath callr and much of the r-lib tooling stack. For several releases it shipped only hardening work: RNG hygiene, safer format strings, signal handling around terminated parents. Version 3.9.0 breaks that pattern with an experimental pipeline class.
◆ Where it's heading
The package is moving from running one subprocess reliably toward orchestrating graphs of them, with bytes flowing between children through kernel pipes rather than being relayed through R. The new linux_pdeathsig argument points the same way, giving callers real lifecycle control over long-running children.
◆ Prediction
Expect the pipeline class to lose its experimental label and gain callr integration if the API holds up across both Unix and Windows.
promises
0.0DEVOPS
promises drops R6 for plain environments and wires async work into OpenTelemetry
◆ Current state
promises supplies the async primitives behind Shiny and plumber. After years of small domain and future() fixes, the last two releases changed both what a promise costs and what it can report: 1.4.0 corrected nested domain ordering and added the first OpenTelemetry integration, and 1.5.0 replaced the R6 promise class with a classed environment while stabilizing the tracing API.
◆ Where it's heading
Two things are being fixed at once. Promise domains - the mechanism that carries context across async boundaries - have been the source of nearly every bug in this window, and they are now being used deliberately as the vehicle for tracing rather than just for error handling. Meanwhile the object itself is being made cheap enough to create in volume.
◆ Prediction
Expect the OpenTelemetry surface to lose its experimental label and pick up the same span coverage Shiny would need end to end; the deprecated ospan function names should be removed in a following release.
Alternatives to processx and promises
Other DevOps 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 processx or promises.
withr
withr rebuilt defer() on base R's own on.exit(), and got much faster for it
htmltools
htmltools spends three releases walking back its own fill-layout opinions
xml2
xml2 relicensed to MIT, then moved its hot accessors from S3 into C
httr
httr's last releases are housekeeping - the package now points users at httr2
magrittr
magrittr rewrote its pipe in C, then base R shipped one and the releases stopped
See all processx alternatives → · See all promises alternatives →
Recent activity from processx and promises
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 3mo agoprocessxprocessx 3.9.0 adds shell-style pipelines between child processes ⚡
- 9mo agopromisesOpenTelemetry spans across async work; R6 dropped for environments ⚡
- 9mo agopromisesNested promise domains fixed; then() gains a tee argument
- 1y agopromisesRealigns future object creation with the future package
- 1y agoprocessxprocessx 3.8.6 restores cloneable process objects for R6 2.6
- 1y agopromisesFixes stack overflow on long promise chains
- 1y agopromisesFixes domains forgotten inside nested handlers
- 2y agoprocessxprocessx 3.8.3 hardens internal printf format strings
- 3y agopromisesfuture_promise() returns early when workers are exhausted
- 3y agoprocessxprocessx 3.8.2 ignores SIGPIPE to avoid callr session freezes
- 3y agoprocessxprocessx 3.8.1 adds opt-in SIGTERM temp-directory cleanup
- 3y agoprocessxprocessx 3.8.0 adds hyperlinked error stacks, fixes system() calls
Frequently asked questions
What is the difference between processx and promises?
They serve adjacent needs but don't currently overlap on shipped themes. processx and promises are shipping at a similar cadence (velocity 0.0 vs 0.0, both within Sparkpulse's "active" band). See the at-a-glance table above for a side-by-side breakdown of velocity, recent sparks, and editorial themes.
Is processx better than promises?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. processx and promises are shipping at a similar cadence (velocity 0.0 vs 0.0, both within Sparkpulse's "active" band). For your specific use case, the alternatives sections above list other DevOps products to evaluate alongside.
What are the best alternatives to processx?
Top processx alternatives in DevOps are ranked by recent ship velocity. Browse the "processx alternatives" section above for the current picks, or visit /alternatives/processx for the full list with editorial commentary on each.
What are the best alternatives to promises?
Top promises alternatives in DevOps are ranked by recent ship velocity. Browse the "promises alternatives" section above for the current picks, or visit /alternatives/promises for the full list with editorial commentary on each.