Model components / Fine-tuned / chat models

Claude Haiku

Anthropic's small, fast Claude tier, built for high-volume low-latency coding and chat where cost and speed matter more than peak reasoning. Sits beneath Sonnet and Opus. Tracked as a tier rather than a point release, with the measured release named in the score note. Closed weights, available through the Anthropic API and the Claude apps.

Tier product, currently shipping Haiku 4.5. Renamed from claude-haiku-4-5 so the slug survives the next generation.

Openness

1 high confidence

1.0

weights: closed
data: closed
code: closed
license: Proprietary(API-only)

Closed by construction and stable across generations. Measured against Claude Haiku 4.5, the generation shipping at the time of scoring.

https://www.anthropic.com/claude/haiku recorded 2026-07-29
Haiku is offered as an API and product tier only, with no weight download

Adoption

4 medium confidence

4.0

High-volume tier by design, but no per-model usage figure is published and it is chosen less often than Sonnet as a default. Directional.

https://www.anthropic.com/claude/haiku recorded 2026-07-29
positioned for high-volume low-latency workloads across the API and Claude apps

Capability

4 medium confidence

4.0

Haiku 4.5 is strong for its size class and competitive with the previous Sonnet generation, but below the current Sonnet, Opus and Fable tiers. Confidence medium - SWE-bench Verified's leaderboard has no submissions since 2025-12-15, so figures are vendor-reported.

https://www.anthropic.com/claude/haiku recorded 2026-07-29
vendor-reported coding and agentic results for the Haiku 4.5 generation

Unchanged since 2026-07-29 (last edited, not re-checked)