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lobstr vs mirai

A side-by-side editorial comparison of lobstr and mirai — release velocity, themes, recent moves, and the top alternatives to consider.

lobstr vs mirai: at a glance

Featurelobstrmirai
SectorAnalyticsAnalytics
Velocity score0.02.5
Sparks · 30d00
Top themesr-lib, introspection, memory, c-apiparallel-computing, async, backpressure, shiny
Last editorial update1h ago2h ago
WebsiteVisit →Visit →

What is lobstr?

R's object inspector is losing its view of the internals as CRAN closes off the private C API.

lobstr exposes R's internal object representation — sizes, addresses, reference counts, abstract syntax trees. Its two most recent releases are both driven by R's move to a restricted public C API: 1.1.3 stopped reporting a vector's truelength and reworked the reference indicator into refs:n, and 1.2.0 changed what sxp(expand = "environment") shows in order to stay compliant. 1.2.0 also adds src() for exploring srcref objects.

Read the full lobstr trajectory →

What is mirai?

mirai removed its dispatcher process and added memory backpressure to the queue.

The async evaluation framework releases roughly monthly and moves fast at the architecture level. In 2.7.0 the dispatcher stopped being a separate process and became a thread, after its loop had already been rewritten in C inside nanonext one release earlier. The same release added an opt-in memory budget for queued task payloads and try_mirai(), which returns NULL immediately rather than blocking when that budget is exhausted.

Read the full mirai trajectory →

lobstr vs mirai: editorial side-by-side

L
lobstr
ANALYTICS
0.0

R's object inspector is losing its view of the internals as CRAN closes off the private C API.

◆ Current state

lobstr exposes R's internal object representation — sizes, addresses, reference counts, abstract syntax trees. Its two most recent releases are both driven by R's move to a restricted public C API: 1.1.3 stopped reporting a vector's truelength and reworked the reference indicator into refs:n, and 1.2.0 changed what sxp(expand = "environment") shows in order to stay compliant. 1.2.0 also adds src() for exploring srcref objects.

◆ Where it's heading

The package is being rebuilt inside a shrinking window of what R permits. Each release trades some introspection depth for API conformance while trying to keep the diagnostic value intact — showing promise expressions instead of internal frame structures, replacing named with a documented refs scale. Where the constraint does not bite, development continues normally: src() is genuinely new, and the environment-binding fixes remove long-standing errors on for-loop and immediate bindings.

◆ Prediction

Expect further conformance work, since the notes describe it as ongoing, with any remaining non-API-dependent readouts either reworked or dropped as R tightens further.

M
mirai
ANALYTICS
2.5

mirai removed its dispatcher process and added memory backpressure to the queue.

◆ Current state

The async evaluation framework releases roughly monthly and moves fast at the architecture level. In 2.7.0 the dispatcher stopped being a separate process and became a thread, after its loop had already been rewritten in C inside nanonext one release earlier. The same release added an opt-in memory budget for queued task payloads and try_mirai(), which returns NULL immediately rather than blocking when that budget is exhausted.

◆ Where it's heading

Two threads of work run together: cutting overhead out of the task path — thread-based dispatcher, in-process transport for synchronous daemons, lower per-element dispatch cost in mirai_map() — and making the framework safe to embed in an event loop, where blocking the host R thread is not acceptable. Deployment reach is growing too, with http_config() launching remote daemons over HTTP APIs and auto-configuring for Posit Workbench. Each release pins a minimum nanonext version, so the two packages advance as one unit.

◆ Prediction

With backpressure in place but opt-in, the open question these notes leave is whether a default memory budget arrives; continued overhead reduction and Shiny-facing non-blocking paths are the safer bet.

Alternatives to lobstr and mirai

Other Analytics 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 lobstr or mirai.

See all lobstr alternatives → · See all mirai alternatives →

Recent activity from lobstr and mirai

Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.

  1. 25d agomiraiMap collection and daemon lifecycle fixes
  2. 2mo agomiraiAgent skill ships in-package; HTTP headers take over auth
  3. 3mo agomiraiDispatcher becomes a thread, and the queue gains a memory budget
  4. 5mo agomiraiParallel RNG seeding leaves experimental status
  5. 5mo agolobstrNew src() for srcrefs; environment bindings stop erroring
  6. 6mo agomiraiRemote daemons over HTTP, and a C dispatcher loop
  7. 8mo agomiraiTelemetry span timing and daemon-switch fix
  8. 9mo agolobstrtruelength reporting dropped for public C API compliance
  9. 4y agolobstrMoves to cpp11, relicensed MIT, adds experimental tree()
  10. 7y agolobstrPROTECT error fixed
  11. 7y agolobstrALTREP sizes computed correctly; obj_addr() stops side-effecting

Frequently asked questions

What is the difference between lobstr and mirai?

They serve adjacent needs but don't currently overlap on shipped themes. mirai 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 lobstr better than mirai?

Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. mirai 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 Analytics products to evaluate alongside.

What are the best alternatives to lobstr?

Top lobstr alternatives in Analytics are ranked by recent ship velocity. Browse the "lobstr alternatives" section above for the current picks, or visit /alternatives/lobstr for the full list with editorial commentary on each.

What are the best alternatives to mirai?

Top mirai alternatives in Analytics are ranked by recent ship velocity. Browse the "mirai alternatives" section above for the current picks, or visit /alternatives/mirai for the full list with editorial commentary on each.