Claude Sonnet 5.5 vs Step 5 Preview
Detailed technical comparison between Claude Sonnet 5.5 (Anthropic) and Step 5 Preview (StepFun). Review live API token pricing, context window capabilities, time-to-first-token latency, and verified benchmark scores side-by-side.
Comparison Snapshot
Tie
Equal CapacityTie
Equal CapabilityTie
Equal SpeedStep 5 Preview
$1.00 / MTokClaude Sonnet 5.5
Claude Sonnet 5.5 is an advanced artificial intelligence model engineered by Anthropic. Tailored for complex multi-step reasoning, programming synthesis, and extended document comprehension, Claude Sonnet 5.5 represents a key architectural iteration in the Anthropic model family. First released in 2026-09-28, it serves enterprise developers, research teams, and autonomous system architects requiring strict instruction compliance. Featuring an input capacity of 1,000,000 tokens (approximately 1,333 words), Claude Sonnet 5.5 processes multi-file code repositories, lengthy technical reports, and complex prompts in a single inference call.
Step 5 Preview
Step 5 Preview is an advanced artificial intelligence model engineered by StepFun. Tailored for complex multi-step reasoning, programming synthesis, and extended document comprehension, Step 5 Preview represents a key architectural iteration in the StepFun model family. First released in 2026-10-08, it serves enterprise developers, research teams, and autonomous system architects requiring strict instruction compliance. Featuring an input capacity of 1,000,000 tokens (approximately 1,333 words), Step 5 Preview processes multi-file code repositories, lengthy technical reports, and complex prompts in a single inference call.
Technical Specifications
🏆 = Superior Spec| Specification | Claude Sonnet 5.5 | Step 5 Preview |
|---|---|---|
| Provider | Anthropic | StepFun |
| Context Window | 1,000,000 tokens | 1,000,000 tokens |
| Agent Suitability | Not yet benchmarked | Not yet benchmarked |
| Time to First Token (TTFT) | No public TTFT data | No public TTFT data |
| Deployment Model | managed api | managed api |
| Production Stability | Beta Access (est.) | Beta Access (est.) |
| API Available | Yes | Yes |
| Released Date | 2026-09-28 | 2026-10-08 |
API Pricing Comparison
Input Price per Million Tokens
Claude Sonnet 5.5
$2.00
Step 5 Preview
$1.00
Output Price per Million Tokens
Claude Sonnet 5.5
$10.00
Step 5 Preview
$2.70
💡 Cost Ratio: Step 5 Preview is 2.0x cheaper per input token than Claude Sonnet 5.5.
Want to test both models live?
Run side-by-side prompt benchmarks in our dynamic multi-model Sandbox. Compare execution speeds, latency metrics, and compute actual costs in real-time.
Benchmark Performance Metrics
Standardized Scores (0–100%)Scores show verified raw accuracy percentages across standardized AI evaluation suites. Higher bars indicate superior performance in that domain.
Claude Sonnet 5.5 Quirks & Gotchas
No developer gotchas reported.
Step 5 Preview Quirks & Gotchas
No developer gotchas reported.
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