zarr-python
Zarr's package split keeps producing standalone tools: a server, now a lazy indexer.
Comparison · DevOps
Fiber vs promises
A side-by-side editorial comparison of Fiber and promises — release velocity, themes, recent moves, and the top alternatives to consider.
Fiber vs promises: at a glance
What is Fiber?
Fiber v3 has sat in release candidate for months while v2 gets one-line patches
The feed carries two lines that barely touch. Fiber v2 receives narrow maintenance releases — a lock cleanup, an X-Real-IP backport, an HTML escaping fix, a CVE patch — most containing a single merged PR. The v3 line, last visible here at rc.3, is where the actual work is: native net/http and fasthttp handler support, Express-style request and response handlers, HostClient and LBClient in the client package.
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.
Fiber vs promises: editorial side-by-side
Fiber
2.5DEVOPS
Fiber v3 has sat in release candidate for months while v2 gets one-line patches
◆ Current state
The feed carries two lines that barely touch. Fiber v2 receives narrow maintenance releases — a lock cleanup, an X-Real-IP backport, an HTML escaping fix, a CVE patch — most containing a single merged PR. The v3 line, last visible here at rc.3, is where the actual work is: native net/http and fasthttp handler support, Express-style request and response handlers, HostClient and LBClient in the client package.
◆ Where it's heading
v3 is the answer to Fiber's longest-standing objection, that building on fasthttp cuts a project off from the net/http middleware ecosystem. Making both handler styles native reframes Fiber as compatible rather than separate. But rc.3 dates to late 2025 and nothing newer has landed in this feed, while v2 patches keep arriving through August — a long release candidate stretch that leaves users choosing between a stable branch in pure maintenance and a v3 that has not been declared final.
◆ Prediction
The next meaningful entry is either a v3.0.0 final or a further RC; until one lands, expect the v2 line to continue receiving single-PR backports and security patches.
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 Fiber 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 Fiber 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.
httpuv
httpuv ships almost nothing, which is what you want from the web server under Shiny
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
See all Fiber alternatives → · See all promises alternatives →
Recent activity from Fiber and promises
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 1d agoFiberIdempotency middleware releases MemoryLock keys on unlock
- 1mo agoFiberX-Real-IP overwrite fix backported to v2
- 3mo agoFiberCtx.Format now escapes HTML output
- 5mo agoFiberSecurity patch for GHSA-mrq8-rjmw-wpq3
- 6mo agoFiberMount improvements and limiter middleware fixes
- 8mo agoFiberv3 RC adds native net/http and Express-style handlers ⚡
- 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 agopromisesFixes stack overflow on long promise chains
- 1y agopromisesFixes domains forgotten inside nested handlers
- 3y agopromisesfuture_promise() returns early when workers are exhausted
Frequently asked questions
What is the difference between Fiber and promises?
They serve adjacent needs but don't currently overlap on shipped themes. Fiber 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 Fiber better than promises?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. Fiber 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 DevOps products to evaluate alongside.
What are the best alternatives to Fiber?
Top Fiber alternatives in DevOps are ranked by recent ship velocity. Browse the "Fiber alternatives" section above for the current picks, or visit /alternatives/fiber 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.