Claude Sonnet 4.5
anthropic/claude-sonnet-4-5-20250929The Claude 4.5 generation Sonnet
Use this model in the playground
Create an agent with this model, try it in the playground, and call your saved agent through the API.
Playground catalog rates, including your 5% Free-plan fee. Included usage applies first, then prepaid credits. Cached tokens and tools can have separate charges. Direct chat-completions routing is not currently listed for this exact model; use its saved agent ID with the Agents API.
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Choose how to use Claude Sonnet 4.5
Playground
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Model capabilities below describe the underlying model. Available playground features depend on its provider.
API
Connect your app with a Gizmo API key. Choose fastest or cheapest, stream text responses, and inspect timing, tokens, and charges in request logs.
Direct chat-completions routing is not listed for this exact model. Create a saved agent with this model and call it using the Agents API.
Provider price + a transparent platform fee
| Rate | Provider baseline | Free plan · 5% fee | Paid plan · 4% fee |
|---|---|---|---|
| Input / 1M tokens | $3 | $3.15 | $3.12 |
| Output / 1M tokens | $15 | $15.75 | $15.6 |
Legacy chat image rates use the catalog baseline. The dedicated image playground shows separate estimates and settles the provider’s metered usage. API rates are current routing ceilings; final API charges use provider-reported cost plus your fee. Cheapest routing compares eligible OpenRouter and Cheaper Inference rates for the same model; savings are not guaranteed. Cached input or other provider charges may differ. Compare all model rates and verified discounts →
How your plan pays for usage
API and playground share one included allowance. Usage including the fee draws from that allowance first, then your prepaid credits. Plans bill monthly; included usage resets weekly: Free $1, Starter $5, Growth $25, Scale $50.
A $1 provider charge becomes $1.05 on Free or $1.04 on a paid plan before included usage is applied. Plan eligibility still applies in the playground.
Free models and limits
Zero-cost models stay $0, including the fee, and do not consume your dollar allowance. Free accounts can make 1,000 free-model API requests per calendar month, resetting in UTC. Admitted requests count even if the provider fails.
Free includes 20 API requests/minute and 6 playground messages/minute. Paid plans raise these limits. See plan limits.
Before a text API request, Gizmo temporarily reserves included usage and, if necessary, prepaid credit for the model’s full context plus your maximum output. Image jobs reserve twice their displayed estimate. Unused funds return after metering. This hold can exceed the final charge; unconfirmed usage remains marked pending.
Overview
Claude Sonnet 4.5 is Anthropic’s most advanced Sonnet model to date, optimized for real-world agents and coding workflows. It delivers state-of-the-art performance on coding benchmarks such as SWE-bench Verified, with improvements across system design, code security, and specification adherence. The model is designed for extended autonomous operation, maintaining task continuity across sessions and providing fact-based progress tracking.
Sonnet 4.5 also introduces stronger agentic capabilities, including improved tool orchestration, speculative parallel execution, and more efficient context and memory management. With enhanced context tracking and awareness of token usage across tool calls, it is particularly well-suited for multi-context and long-running workflows. Use cases span software engineering, cybersecurity, financial analysis, research agents, and other domains requiring sustained reasoning and tool use.
Strengths
- Strong coding for its price class
Best for
Benchmarks
Artificial Analysis indices independent, 0–100
Design Arena head-to-head, human-voted
| Category | Elo | Win rate | Rank |
|---|---|---|---|
| ASCII art | 1225 | 56.1% | #20 |
| Mobile apps (agent) | 1174 | 52.9% | #26 |
| Full-stack agents (agent) | 1059 | 43.7% | #33 |
| Web apps (agent) | 1080 | 43.2% | #33 |
| SVG | 1143 | 52.2% | #49 |
| Code | 1199 | 51.5% | #51 |
| 3D scenes | 1187 | 51% | #52 |
| Game dev | 1191 | 51.1% | #54 |
Capabilities
Reasoning is available.
Sampling controls: temperature, top_p, top_k, max_tokens. Defaults: top_k null, top_p 1, temperature 1, presence_penalty null, frequency_penalty null, repetition_penalty null.
Requests pass through the provider’s content moderation.
Pricing on Gizmo
These are provider baseline rates before Gizmo’s 5% Free-plan or 4% paid-plan fee. Your included usage covers charges first; overage uses prepaid credits. See the fee-inclusive comparison above.
Provider baseline rates
- Input
- $3 / 1M
- Cached input
- $0.3 / 1M
- Cache write
- $3.75 / 1M
- Output
- $15 / 1M
- Web search
- $0.01 / call
Examples before the platform fee
- Typical chat turn
- $0.0135 2k in · 500 out
- $1 of input
- ≈ 333k tokens
- $1 of output
- ≈ 67k tokens
- Full context, once
- $0.60
Providers and pricing
One way to run Claude Sonnet 4.5 on Gizmo.
| Provider | Route | Input / 1M | Output / 1M | Context | Uptime 24h |
|---|---|---|---|---|---|
| AnthropicLowest price | Direct | $3.00 | $15.00 | 200k | 99.6% |
Rates are each provider’s, per million tokens, before Gizmo’s 5% (Free) or 4% (paid) fee. “Cheapest” routing starts at the top of this list; “Fastest” starts with the model’s maker.
More from Anthropic
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Run Claude Sonnet 4.5 in under a minute
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Chat, research, create
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