httpuv
httpuv ships almost nothing, which is what you want from the web server under Shiny
Comparison · DevOps
promises vs Rollbar
A side-by-side editorial comparison of promises and Rollbar — release velocity, themes, recent moves, and the top alternatives to consider.
promises vs Rollbar: at a glance
| Feature | promises | Rollbar |
|---|---|---|
| Sector | DevOps | DevOps |
| Velocity score | 0.0 | 6.3 |
| Sparks · 30d | 0 | 1 |
| Top themes | async, observability, performance, shiny | ai-agents, root-cause-analysis, credit-pricing, github-integration |
| Last editorial update | 49m ago | 17h ago |
| Website | Visit → | — |
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.
What is Rollbar?
Rollbar's AI arc reaches its endpoint: the error tracker now opens the pull request.
Rollbar spent 2026 converting error tracking into an AI workflow, and the Resolve agent is where that lands — production errors now come back as pull requests carrying a fix, test results, and a root cause. The monetization moved with it: AI features bill against a credit pool sold separately from plan tier, with no per-seat charge. Around that core, the platform work has been deliberately unglamorous, covering account-wide API tokens, an MCP server, session replay timelines, and a settings UI rebuild.
promises vs Rollbar: editorial side-by-side
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.
Rollbar
6.3DEVOPS
Rollbar's AI arc reaches its endpoint: the error tracker now opens the pull request.
◆ Current state
Rollbar spent 2026 converting error tracking into an AI workflow, and the Resolve agent is where that lands — production errors now come back as pull requests carrying a fix, test results, and a root cause. The monetization moved with it: AI features bill against a credit pool sold separately from plan tier, with no per-seat charge. Around that core, the platform work has been deliberately unglamorous, covering account-wide API tokens, an MCP server, session replay timelines, and a settings UI rebuild.
◆ Where it's heading
The product is moving from telling you what broke to handing you the change that fixes it, and each release since April closed part of that loop — root cause in April, cheap access to it in June, codebase reach via MCP and account tokens in July, code generation and test execution in August. Credits rather than seats are the pricing unit, which lets Rollbar put agent features on the free plan without cannibalizing tier upgrades. Moving code access onto a dedicated GitHub App suggests that reach is now treated as infrastructure rather than an integration.
◆ Prediction
Expect Resolve to exit beta with credit consumption as the primary lever, and the agent to reach past single-error fixes — the cross-project correlation and telemetry already assembled for root cause analysis are the obvious next inputs.
Alternatives to promises and Rollbar
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 promises or Rollbar.
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 promises alternatives → · See all Rollbar alternatives →
Recent activity from promises and Rollbar
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 1d agoRollbarResolve now writes the PR that fixes your errors ⚡
- 16d agoRollbarOne Token, Every Project
- 1mo agoRollbarDebug Race Conditions in Real Time with Session Replay's Event Timeline
- 2mo agoRollbarYou don't need a paid plan to use AI Root Cause Analysis ⚡
- 3mo agoRollbarVersions & Deploys, now on your Dashboard
- 4mo agoRollbarAI Root Cause Analysis ⚡
- 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 promises and Rollbar?
They serve adjacent needs but don't currently overlap on shipped themes. Rollbar is currently shipping more aggressively (velocity 6.3 vs 0.0), with 1 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 promises better than Rollbar?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. Rollbar is currently shipping more aggressively (velocity 6.3 vs 0.0), with 1 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 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.
What are the best alternatives to Rollbar?
Top Rollbar alternatives in DevOps are ranked by recent ship velocity. Browse the "Rollbar alternatives" section above for the current picks, or visit /alternatives/rollbar for the full list with editorial commentary on each.