← Back to home
Comparison · Infra & APIs

CBTF vs Depot

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

CBTF vs Depot: at a glance

FeatureCBTFDepot
SectorInfra & APIsInfra & APIs
Velocity score0.06.3
Sparks · 30d01
Top themestesting, fuzzing, r-package, developer-toolsci-cd, build-acceleration, test-intelligence, git-hosting
Last editorial update56m ago5d ago
WebsiteVisit →

What is CBTF?

A fuzzer for R packages that grew from one argument at a time to parallel runs across whole namespaces.

CBTF throws deliberately problematic inputs at exported functions and reports which ones error, warn, or survive. It now covers 85 input classes, fuzzes multiple named arguments per call, runs in parallel with a per-function timeout, and reports results as a classed object with print, summary, length, and whitelist methods for pruning false positives. Output control has been refined repeatedly — the latest release adds grouping by input or by function and a summary-only mode.

Read the full CBTF trajectory →

What is Depot?

Depot keeps absorbing the CI stack — tests, networking, runners, now its own git host.

Depot has moved well past build caching. Test results reached general availability in July with org-wide flaky, slow, and recurring failure analytics plus timing-based shard splitting; Sherlock's AI analysis became available on any run rather than only failed ones; and CI jobs can join a Tailscale tailnet to reach private services. The runner fleet now defaults to macOS 26 on M4 hardware, Depot CI understands GitHub stacked pull requests, and Depot Code — a diskless git server backed by blob storage — entered private beta.

Read the full Depot trajectory →

CBTF vs Depot: editorial side-by-side

C
CBTF
INFRA · APIS
0.0

A fuzzer for R packages that grew from one argument at a time to parallel runs across whole namespaces.

◆ Current state

CBTF throws deliberately problematic inputs at exported functions and reports which ones error, warn, or survive. It now covers 85 input classes, fuzzes multiple named arguments per call, runs in parallel with a per-function timeout, and reports results as a classed object with print, summary, length, and whitelist methods for pruning false positives. Output control has been refined repeatedly — the latest release adds grouping by input or by function and a summary-only mode.

◆ Where it's heading

The package has moved from a script-shaped tool to a test-suite component. The single-argument, sequential fuzz() of the early releases could not finish a large namespace or survive a function that simply hangs; the mirai rewrite fixed both, and multi-argument support widened what a run can actually reach. Nearly everything since has gone into making results triageable rather than merely produced: whitelisting, result classes, grouping, and terminal output that fits real function signatures. Note that the 0.1.0 through 0.3.0 entries carry backfilled timestamps recorded in reverse order within under a minute, so their published dates do not reflect release order.

◆ Prediction

The steady expansion of the input catalogue from 70 to 85 with a new time class suggests more input classes are the cheapest next win; the reporting surface is now detailed enough that machine-readable output for CI would be the natural follow-on.

D
Depot
INFRA · APIS
6.3

Depot keeps absorbing the CI stack — tests, networking, runners, now its own git host.

◆ Current state

Depot has moved well past build caching. Test results reached general availability in July with org-wide flaky, slow, and recurring failure analytics plus timing-based shard splitting; Sherlock's AI analysis became available on any run rather than only failed ones; and CI jobs can join a Tailscale tailnet to reach private services. The runner fleet now defaults to macOS 26 on M4 hardware, Depot CI understands GitHub stacked pull requests, and Depot Code — a diskless git server backed by blob storage — entered private beta.

◆ Where it's heading

The pattern is absorbing each adjacent piece of the pipeline that Depot's position already gives it data about. It runs the builds, so it owns test timing, so it can balance shards; it runs the jobs, so it can diagnose them; it hosts the runners, so it can wire private networking into them. Depot Code extends the same logic upstream to source hosting, which would close the loop between repository and runner. A quieter parallel thread keeps moving SDK- and dashboard-only settings into the CLI, stated explicitly as making projects configurable by agents and scripts.

◆ Prediction

Depot Code widening past private beta and binding more tightly to CI is the move the rest of the window sets up. The test work is also positioned to go from reporting to selection — skipping tests a change cannot affect — since Depot now holds the timing and failure history that would require, though the entries stop short of saying so.

Alternatives to CBTF and Depot

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 CBTF or Depot.

See all CBTF alternatives → · See all Depot alternatives →

Recent activity from CBTF and Depot

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

  1. 9d agoDepotmacOS 26 is now the default macOS version for GitHub Actions runners
  2. 16d agoDepotDepot CI now supports native GitHub stacked pull requests
  3. 19d agoDepotSet cache retention when creating a project with --cache-policy-keep-days
  4. 20d agoDepotView and edit project details from the Depot CLI
  5. 21d agoDepotTest results are now generally available
  6. 29d agoDepotAI analysis available for all Depot CI workflows and jobs
  7. 1mo agoCBTFTime inputs added; results groupable by input or function
  8. 6mo agoCBTFParallel fuzzing with timeouts, and multi-argument support
  9. 0y agoCBTFWhitelisting for false positives, plus clearer result semantics
  10. 1y agoCBTFFunction discovery skips unfuzzable functions; failures no longer crash
  11. 1y agoCBTFFirst release; notes carry only a website link
  12. 1y agoCBTFRaw results returned as an object with summary and print methods

Frequently asked questions

What is the difference between CBTF and Depot?

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

Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. Depot 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 Infra & APIs products to evaluate alongside.

What are the best alternatives to CBTF?

Top CBTF alternatives in Infra & APIs are ranked by recent ship velocity. Browse the "CBTF alternatives" section above for the current picks, or visit /alternatives/caught-by-the-fuzz for the full list with editorial commentary on each.

What are the best alternatives to Depot?

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