Resend
Resend is wiring itself into every agent runtime it can reach, and now adding the controls to stop a send.
A side-by-side editorial comparison of SLmetrics and WorkOS — release velocity, themes, recent moves, and the top alternatives to consider.
| Feature | SLmetrics | WorkOS |
|---|---|---|
| Sector | Infra & APIs | Infra & APIs |
| Velocity score | 0.0 | 8.8 |
| Sparks · 30d | 0 | 2 |
| Top themes | machine-learning, model-evaluation, performance, cpp-backend | identity, authentication, ai-agents, scim |
| Last editorial update | 2d ago | 14h ago |
| Website | Visit → | — |
A young ML metrics package rewrote its own backend twice in six months chasing speed.
SLmetrics provides supervised learning evaluation metrics for R — confusion matrices, classification and regression measures, ROC and precision-recall curves — with the computation pushed into C++. After a series of pre-releases it now runs on an Armadillo backend, supports OpenMP parallelism and LAPACK/BLAS, and reports 5-20x speedups over its earlier implementations. The API has been reshaped for extensibility, with an estimator argument replacing the fixed aggregation options.
WorkOS is building identity for agents while quietly fixing the sign-up funnel.
WorkOS ships several small entries a week, and August splits cleanly in two. One half is authentication housekeeping for human users: an Android SDK, deliverability checks that reject undeliverable addresses at sign-up, invitation acceptance counting as email verification, and a reversible SCIM proxy for migrating directory connections without downtime. The other half is agent infrastructure — Agent Registration via the auth.md protocol, and the Pipes Token Proxy that calls third-party APIs on a user's behalf without the application ever touching their token.
SLmetrics provides supervised learning evaluation metrics for R — confusion matrices, classification and regression measures, ROC and precision-recall curves — with the computation pushed into C++. After a series of pre-releases it now runs on an Armadillo backend, supports OpenMP parallelism and LAPACK/BLAS, and reports 5-20x speedups over its earlier implementations. The API has been reshaped for extensibility, with an estimator argument replacing the fixed aggregation options.
Every release in this timeline is about making the same metrics compute faster or compose better. The backend moved from Rcpp to plain C++, gained OpenMP, then was ported wholesale from Eigen to Armadillo with heavy templating. In parallel the author has been widening the API's joints: generic S3 signatures, an extensible estimator argument, and function signatures loose enough that wrapping packages can rename arguments. Bundled datasets and embedded formulas in the docs point at teaching and benchmarking use. The package still labels itself pre-release, which is consistent with how freely it has broken argument names along the way.
A stable non-pre-release version is the natural next step now that the backend has settled on Armadillo, though the repeated willingness to rename arguments suggests more API churn may come first.
WorkOS ships several small entries a week, and August splits cleanly in two. One half is authentication housekeeping for human users: an Android SDK, deliverability checks that reject undeliverable addresses at sign-up, invitation acceptance counting as email verification, and a reversible SCIM proxy for migrating directory connections without downtime. The other half is agent infrastructure — Agent Registration via the auth.md protocol, and the Pipes Token Proxy that calls third-party APIs on a user's behalf without the application ever touching their token.
The agent work is the strategic line. Registration gives an agent an identity of its own instead of a borrowed human session; the token proxy means an application acting for a user never holds the credential. Together they describe a stack where an agent can be authorized, audited and revoked as a first-class principal. The human-auth releases are conversion and migration work — the deliverability check and SCIM Bridge both remove reasons a customer stalls — which is what a developer-infrastructure company does while its next category is still forming.
Registration and the token proxy leave scoping and revocation as the visible gaps, so expect per-agent permissions or consent surfaces next. Whether auth.md gains adoption beyond WorkOS is not something these entries can answer.
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 SLmetrics or WorkOS.
Resend is wiring itself into every agent runtime it can reach, and now adding the controls to stop a send.
DNSControl v5 is feature-frozen with a ship date, and rc9 is pure provider cleanup
Casdoor is spending its release cadence moving auth checks from the client to the server
ESPHome ships on a calendar, and the August beta train is now five builds deep
Strimzi's 1.2.0 candidate closes with a logging fix and nothing else
Prowler's assistant decides what to do with findings; the patches keep the scanner honest
See all SLmetrics alternatives → · See all WorkOS alternatives →
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
They serve adjacent needs but don't currently overlap on shipped themes. WorkOS is currently shipping more aggressively (velocity 8.8 vs 0.0), with 2 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.
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. WorkOS is currently shipping more aggressively (velocity 8.8 vs 0.0), with 2 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.
Top SLmetrics alternatives in Infra & APIs are ranked by recent ship velocity. Browse the "SLmetrics alternatives" section above for the current picks, or visit /alternatives/slmetrics for the full list with editorial commentary on each.
Top WorkOS alternatives in Infra & APIs are ranked by recent ship velocity. Browse the "WorkOS alternatives" section above for the current picks, or visit /alternatives/workos for the full list with editorial commentary on each.