
Claude Sonnet 4
Anthropic's workhorse frontier model: near-flagship capability at a mid-tier price
About
Claude Sonnet 4 launched May 22, 2025 alongside Opus 4 as the practical default in Anthropic's lineup. It kept the 200K context window and $3/$15 pricing of its predecessors but pushed coding performance meaningfully forward, with team-reported SWE-bench numbers well above 3.7 Sonnet. It supports extended thinking, tool use, MCP connectors, and code execution, and it ships on every Claude plan including free. For most production workloads it is the sensible pick: Opus 4 exists for the hardest problems, but Sonnet 4 delivers most of the capability at a fifth of the price and noticeably higher speed.
Specs
Context window
Pricing
Free quota
API access
Weights
Released
Benchmarks
Team-reported: 72.7% SWE-bench Verified
Provider-reported unless a source says otherwise. Benchmarks are marketing-adjacent by nature — treat them as directional.
Use cases
Trust score — 9/10
Scored 9/10 (verified tier, metrics-v1). Evidence: May 22, 2025 launch corroborated across 3 sources; Pricing $3/$15, 200K context, 64K max output consistent; SWE-bench 72.7% labeled team-reported; Free-plan inclusion verified; Opus 4 comparison kept factual.