zarr-python
Zarr's package split keeps producing standalone tools: a server, now a lazy indexer.
Comparison · DevOps
httpuv vs promises
A side-by-side editorial comparison of httpuv and promises — release velocity, themes, recent moves, and the top alternatives to consider.
Shared themes:shiny
httpuv vs promises: at a glance
What is httpuv?
httpuv ships almost nothing, which is what you want from the web server under Shiny
httpuv is the C++ HTTP and WebSocket server that Shiny runs on. Across this window it added exactly one user-facing function - runStaticServer() for serving a directory - and spent every other release on race conditions, compiler and linker changes, CRAN check warnings, and mime type table updates.
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.
httpuv vs promises: editorial side-by-side
httpuv
0.0DEVOPS
httpuv ships almost nothing, which is what you want from the web server under Shiny
◆ Current state
httpuv is the C++ HTTP and WebSocket server that Shiny runs on. Across this window it added exactly one user-facing function - runStaticServer() for serving a directory - and spent every other release on race conditions, compiler and linker changes, CRAN check warnings, and mime type table updates.
◆ Where it's heading
There is no direction here in the usual sense, and that is the honest read: the package is a stable foundation whose releases are triggered by the toolchain moving, by R-devel warnings, or by a threading bug surfacing under load. The one recurring theme with substance is connection reliability - WebSocket keepalive pings, race conditions in the I/O thread - which is what actually breaks Shiny apps in production.
◆ Prediction
Expect continued small releases tracking Rtools, R-devel and mime data, with any substantive change most likely coming from a threading or WebSocket issue reported by Shiny users rather than from planned work.
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 httpuv 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 httpuv or promises.
ellipsis
ellipsis' checks live in rlang now; the package is a compatibility shim.
clock
clock is turning calendar conventions lubridate hard-coded into parameterized types.
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
See all httpuv alternatives → · See all promises alternatives →
Recent activity from httpuv and promises
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 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 agohttpuvServes .wasm as application/wasm; mime table refreshed
- 1y agopromisesFixes stack overflow on long promise chains
- 1y agopromisesFixes domains forgotten inside nested handlers
- 2y agohttpuvrunStaticServer() survives a failed browser launch
- 2y agohttpuvRtools build file update and macOS zlib linking fix
- 2y agohttpuvFixes an R CMD check warning on error format strings
- 2y agohttpuvrunStaticServer() serves a directory of static files
- 3y agopromisesfuture_promise() returns early when workers are exhausted
- 3y agohttpuvFixes a race condition introduced in 1.6.10
Frequently asked questions
What is the difference between httpuv and promises?
Both compete on the same themes — shiny — within DevOps. httpuv 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 httpuv better than promises?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. httpuv 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 httpuv?
Top httpuv alternatives in DevOps are ranked by recent ship velocity. Browse the "httpuv alternatives" section above for the current picks, or visit /alternatives/httpuv 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.