humind
The MSNI humanitarian needs framework as code, rewritten and re-broken every year
Comparison · Infra & APIs
Skipper vs slendr
A side-by-side editorial comparison of Skipper and slendr — release velocity, themes, recent moves, and the top alternatives to consider.
Skipper vs slendr: at a glance
What is Skipper?
Skipper trims a 4x memory regression out of routesrv, days after shipping h2c
Zalando's HTTP router ships patch tags almost daily, and most carry a single dependency bump or a one-line auth fix. The substance in this window is v0.27.63, which stops routesrv holding an uncompressed route tree alongside the compressed buffer: retained memory in the release's own benchmark falls from 30.7 MB to 2.0 MB, undoing most of the 4x increase zone-aware routing had introduced. Around it sit narrow auth repairs, and an eskip parser change that finally accepts negative numeric arguments in predicates and filters.
What is slendr?
Population-genetic simulation in R, opened up to selection and finally easier to install.
slendr specifies spatial and non-spatial population-genetic models in R and simulates them through SLiM or msprime, returning tree sequences that tskit then analyses. Two threads dominate the current releases: keeping in step with fast-moving backends, with SLiM 5.1, pyslim 1.1.0 and Python 3.13 now required, and reducing the setup burden that its Python dependency imposes. Version 1.5.0 adds ephemeral uv-based virtual environments, so init_env(uv = TRUE) can stand in for creating a permanent environment with setup_env().
Skipper vs slendr: editorial side-by-side
Skipper
5.0INFRA · APIS
Skipper trims a 4x memory regression out of routesrv, days after shipping h2c
◆ Current state
Zalando's HTTP router ships patch tags almost daily, and most carry a single dependency bump or a one-line auth fix. The substance in this window is v0.27.63, which stops routesrv holding an uncompressed route tree alongside the compressed buffer: retained memory in the release's own benchmark falls from 30.7 MB to 2.0 MB, undoing most of the 4x increase zone-aware routing had introduced. Around it sit narrow auth repairs, and an eskip parser change that finally accepts negative numeric arguments in predicates and filters.
◆ Where it's heading
Two threads run through the recent tags. The data path keeps getting real work - leastRequests balancing, then h2c end to end in v0.27.57, now the memory cost of zone-aware routing being paid back. The auth filters, by contrast, are only being maintained: token introspection, grant auth, and now the OIDC Referer handling are fixes rather than new capability, and several are follow-ups to each other rather than independent bugs.
◆ Prediction
Zone-aware routing looks like the source of the recent memory attention, so expect further tuning around route storage and the hash computation done on every pull, which the release's second benchmark already isolates. The OIDC cookie change is the second link in an auth chain that started with the grant-auth fix, and is likely to draw another follow-up.
slendr
0.0INFRA · APIS
Population-genetic simulation in R, opened up to selection and finally easier to install.
◆ Current state
slendr specifies spatial and non-spatial population-genetic models in R and simulates them through SLiM or msprime, returning tree sequences that tskit then analyses. Two threads dominate the current releases: keeping in step with fast-moving backends, with SLiM 5.1, pyslim 1.1.0 and Python 3.13 now required, and reducing the setup burden that its Python dependency imposes. Version 1.5.0 adds ephemeral uv-based virtual environments, so init_env(uv = TRUE) can stand in for creating a permanent environment with setup_env().
◆ Where it's heading
Since the 1.0.0 release added non-neutral simulation, the work has shifted from capability to friction. A large share of recent notes concerns Python environment handling, conda activation races on Windows, dependency pruning that made shiny optional, and argument names that misled users, as when gene_flow()'s rate argument turned out to mean total ancestry proportion rather than a rate. That is the profile of a package whose scientific surface is settled and whose remaining problems are the ones users actually hit.
◆ Prediction
Expect the uv-based environment path to move from fallback to default once it has proven itself, given the notes already describe an environment variable for making it so. The deprecated rate argument in gene_flow() is explicitly slated for removal in a future major release, which is the clearest signal here of what a 2.0 would contain.
Alternatives to Skipper and slendr
Other Infra & APIs 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 Skipper or slendr.
inlabru
A Bayesian spatial modelling package rebuilding its foundations one breaking release at a time
afcharts
UK government chart styling in ggplot2, chasing ggplot2 v4 and stretching its palette to five.
coga
A gamma-convolution density package that reached completion in 2018 and has coasted since.
smam
Animal-movement models in R, where new stochastic processes arrive years apart.
baseq
A basic DNA and RNA sequence toolkit that went quiet for three years, then jumped to 2.0.
See all Skipper alternatives → · See all slendr alternatives →
Recent activity from Skipper and slendr
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 20h agoSkipperMove OIDC flow protection from Referer to cookies
- 21h agoSkipperv0.27.63: Store routes compressed-only, decompress on demand (#4198)
- 1d agoSkipperEskip predicates and filters accept negative numbers
- 1d agoSkipperFix token introspection handling
- 1d agoSkipperFix grant auth flow
- 2d agoSkipperUpdate outdated golang.org/x dependencies
- 1mo agoslendrEphemeral uv Python environments remove the setup step
- 7mo agoslendrgene_flow() separates migration rate from ancestry proportion
- 9mo agoslendrshiny made optional; SLiM 5.1 and Python 3.13 required
- 1y agoslendrconda activation reverted to a slower but reliable path
- 1y agoslendrBackends raised to SLiM 5.0, tskit 0.6.4 and msprime 1.3.4
- 1y agoslendrNon-neutral models arrive; slim() interface simplified ⚡
Frequently asked questions
What is the difference between Skipper and slendr?
They serve adjacent needs but don't currently overlap on shipped themes. Skipper is currently shipping more aggressively (velocity 5.0 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 Skipper better than slendr?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. Skipper is currently shipping more aggressively (velocity 5.0 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 Infra & APIs products to evaluate alongside.
What are the best alternatives to Skipper?
Top Skipper alternatives in Infra & APIs are ranked by recent ship velocity. Browse the "Skipper alternatives" section above for the current picks, or visit /alternatives/skipper for the full list with editorial commentary on each.
What are the best alternatives to slendr?
Top slendr alternatives in Infra & APIs are ranked by recent ship velocity. Browse the "slendr alternatives" section above for the current picks, or visit /alternatives/slendr for the full list with editorial commentary on each.