Anthropic Claude API

Claude Haiku 5.5 is the small, low-cost model in Anthropic's 5.5 family, released on October 7, 2026 and available through the API as anthropic/claude-haiku-5-5. It has a 1M token context window and up to 128k output tokens. Pricing is $0.10 per million input tokens and $0.50 per million output tokens for requests under 100,000 tokens, down from $1 and $5 for Haiku 4.5, and $0.50 and $2.50 above that. Effort levels range from low to max, with medium as the default. Anthropic reports 72.4% on OSWorld 2.1 (offline subset, Haiku 4.5: 15.7%) and 39.2% on Terminal-Bench 4.0 at maximum effort (Haiku 4.5: 0.0%). On the same tests GPT-6 Luna scores 48.9% and 16.4%. It is aimed at summarizing documents, classifying information, querying databases, and handling subtasks for larger agents. Anthropic recommends Opus and Sonnet for demanding coding work.

Claude Sonnet 5.5 is a mid-tier model from Anthropic, released on September 28, 2026 and available through the API as anthropic/claude-sonnet-5-5. It accepts text, image, and PDF input, with a 1M token context window and up to 128k output tokens. Pricing is $2 per million input tokens and $10 per million output tokens, the same as Claude Sonnet 5. Anthropic says it generates output more than 30% faster than Sonnet 5 and can cut the cost of a task by up to 30%, because it uses fewer tokens and fewer tool calls. Anthropic reports 70.6% on Terminal-Bench 4.0 (Sonnet 5: 10.3%) and 80.1% on OSWorld 2.1 (Sonnet 5: 57.0%). It is aimed at well-scoped everyday tasks, bug fixing, agentic coding, and producing documents, slides, and spreadsheets.

Claude Opus 5.5 is Anthropic's newest flagship model, released September 22, 2026 as the successor to Claude Opus 5. Anthropic positions it for agentic coding and long-running autonomous work. Reported benchmark scores include 66.4% on Terminal-Bench 4.0 (up from 52.3% for Opus 5), 54.4% on FrontierCode, 40% on AutomationBench (up from 26.9%), 81.8% on the OSWorld 2.0 computer-use benchmark, and 67.7% on Humanity's Last Exam with tools. It runs about 30% faster than Opus 5 and costs roughly 40% less on typical workloads, at $4 per million input tokens and $20 per million output tokens, a 1M-token context window, and 128K max output tokens. That combination of long-horizon coding performance, multimodal input (text, image, PDF), tool calling, and lower cost makes it a fit for developers building coding agents, codebase-wide migrations, and research or analysis pipelines through the API.

Claude Fable 5.1 is Anthropic's successor to Claude Fable 5, released September 1, 2026, about three months after Fable 5. Anthropic also released a companion model, Claude Mythos 5.1, available only through trusted access programs; both share the same underlying model with different safety safeguards. On SWE-bench Pro it scores 81.2%, ahead of Fable 5's 80% and Mythos 5's 80.3%. On Terminal-Bench-Science, a scientific-research agentic benchmark, it reaches 52.6%, more than double Fable 5's 24.7% and ahead of GPT-5.6 Sol's 22.4%. On Terminal-Bench 4.0 for agentic coding it scores 55.8%, versus 42.0% for Fable 5 and 37.3% for GPT-5.6 Sol. Priced at $10/$50 per million input/output tokens, unchanged from Fable 5, with cache reads cut 75% to $0.25 per million tokens. It offers a 1,000,000-token context window, 128,000-token max output, and tool calling. It fits developers running long-horizon agentic coding and research pipelines who want Fable-tier reasoning at lower cost.

Claude Opus 5 is Anthropic's flagship model, released July 24, 2026 as the successor to Claude Opus 4.8. Anthropic positions it as approaching the performance of its higher-tier Claude Fable 5 model at roughly half the token cost, built for agentic coding, computer use, and long-horizon knowledge work. On the ARC-AGI-3 novel problem-solving benchmark, Opus 5 scores 30.2%, roughly four times GPT-5.6 Sol's 7.8% and twenty times Opus 4.8's 1.5%. On the GDPval-AA v2 knowledge-work benchmark, it reaches an Elo of 1,861, ahead of Fable 5 (1,747) and GPT-5.6 Sol (1,736). Priced at $5 per million input tokens and $25 per million output tokens, unchanged from Opus 4.8, it offers a 1,000,000-token context window, 128,000-token max output, and tool calling. It fits developers building coding agents and automation pipelines that need strong reasoning at Opus-level pricing.

Claude Opus 5 Fast is a high-speed configuration of Anthropic's Opus 5 flagship model, generating output tokens at roughly 2.5x the speed of standard Opus 5. It runs the same Opus 5 model, which Anthropic says outperforms Opus 4.8 on agentic coding, computer use, and knowledge work, and approaches Fable 5's performance at roughly half the cost. Fast mode pricing is $10/$50 per million input/output tokens, twice the price of standard Opus 5 ($5/$25) and in line with what Opus 4.8 Fast cost. It supports the full 1M token context window and 128k max output tokens. Choose Opus 5 Fast for latency-sensitive agentic pipelines, live coding sessions, and real-time workflows where throughput matters. For cost-sensitive or batch workloads, standard Opus 5 offers the same intelligence at half the price.

Claude Sonnet 5 is Anthropic's newest Sonnet-tier model, released June 30, 2026 as the successor to Sonnet 4.6. Anthropic built it to be the most agentic Sonnet yet, with gains in planning, tool use, coding, and multi-step reasoning that bring it close to Opus 4.8 quality at a lower price. On SWE-bench Pro it scores 63.2%, up from Sonnet 4.6's 58.1% and ahead of GPT-5.5's 58.6%, though still behind Opus 4.8's 69.2%. On Terminal-Bench 2.1 it reaches 80.4% versus Sonnet 4.6's 67.0%, and on the OSWorld-Verified computer-use benchmark it posts 81.2% against Sonnet 4.6's 78.5%. It targets developers running agentic coding pipelines, automation workflows, and tool-heavy tasks who want most of Opus-tier capability without Opus pricing. It launched at $2/$10 per million input/output tokens as introductory pricing through August 31, 2026, and that price has continued as the standard rate. Max output tokens increased from 64,000 to 128,000 after launch.

Claude Fable 5 is Anthropic's most capable generally available model — a publicly released, safety-hardened version of its frontier Mythos-class system, launched June 2026. It is state-of-the-art on nearly every benchmark Anthropic tested, with its lead over prior Claude models growing the longer and more complex the task. It scores 80.3% on SWE-bench Pro, well ahead of Claude Opus 4.8 (69.2%) and GPT-5.5 (58.6%). During early testing, Stripe used it to run a codebase-wide migration in a day that would have taken a team over two months by hand. It's also Anthropic's new state-of-the-art for vision tasks and can work autonomously longer than any previous Claude model. Priced at $10/$50 per million input/output tokens — less than half the cost of Claude Mythos Preview — it targets developers building agentic coding pipelines, vision-heavy workloads, and long-horizon autonomous tasks. Queries on a small set of sensitive topics fall back to Opus 4.8 (on average under 5% of sessions).

Claude Opus 4.8 is Anthropic's latest flagship AI model, building on Opus 4.7 with improvements across coding, reasoning, and knowledge work — at the same price point. The model excels at complex, multi-step agentic workflows including coding, financial analysis, legal reasoning, and browser-based computer use. Early testers report it outperforms both prior Opus models and GPT-5.5 across several agentic benchmarks. Notably, it's around four times less likely than Opus 4.7 to let flaws in generated code pass without flagging them. Opus 4.8 supports configurable effort levels, letting developers trade quality against speed and token cost. A fast mode operates at 2.5× speed. Priced at $5/$25 per million input/output tokens, it targets teams running autonomous agents, analysis pipelines, and long-running async workflows where reliability and judgment are critical.

Claude Opus 4.8 Fast is a high-speed configuration of Anthropic's latest flagship model, delivering up to 2.5x faster output token generation at significantly lower cost than previous fast variants. It runs the same Opus 4.8 model — which improves on Opus 4.7 in agentic coding (69.2% vs 64.3%), multidisciplinary reasoning with tools (57.9% vs 54.7%), and knowledge work — but optimized for lower latency. Fast mode pricing is $10/$50 per million input/output tokens, three times cheaper than fast mode for Opus 4.6 and 4.7 ($30/$150). It supports the full 1M token context window and 128k max output tokens. Choose Opus 4.8 Fast for latency-sensitive agentic pipelines, live coding sessions, and real-time workflows where throughput matters. For cost-sensitive or batch workloads, standard Opus 4.8 offers the same intelligence at half the price.

Claude Opus 4.7 Fast is a high-speed configuration of Anthropic's most capable model, delivering up to 2.5x faster output token generation with no reduction in quality or capabilities. It runs the same Opus 4.7 model — which scores 87.6% on SWE-bench Verified (up from 80.8% on Opus 4.6), 94.2% on GPQA Diamond, and 69.4% on Terminal-Bench 2.0 — but optimized for lower latency at premium pricing ($30/$150 per MTok). It supports the full 1M token context window and 128k max output tokens. Fast mode benefits are focused on output tokens per second, not time to first token. It is ideal for latency-sensitive agentic workflows, live coding sessions, and real-time tasks where response speed matters. For cost-sensitive or batch workloads, standard Opus 4.7 offers the same intelligence at lower cost.

Claude Opus 4.7 is Anthropic's most capable generally available model, built for complex reasoning and agentic coding. It offers a step-change improvement in long-horizon agentic work over its predecessor, Opus 4.6, along with strong gains in knowledge work, vision, and file-system-based memory. The model supports a 1M-token context window, 128k max output tokens, and adaptive thinking. It introduces high-resolution image input (up to 2576px / 3.75MP), a new `xhigh` effort level for demanding coding tasks, and task budgets (beta) that let the model self-moderate token usage across an agentic loop. Priced at $5 / $25 per million input/output tokens. Best suited for developers building autonomous agents, multi-step coding workflows, and vision-heavy pipelines where reliability and depth of reasoning matter most.

Claude Opus 4.6 Fast is a high-speed configuration of Anthropic's most intelligent model, delivering up to 2.5x faster output token generation with no reduction in quality or capabilities. It runs the same Opus 4.6 model — state-of-the-art on benchmarks like Terminal-Bench 2.0 for agentic coding, Humanity's Last Exam for multidisciplinary reasoning, and GDPval-AA for professional knowledge work — but optimized for lower latency at premium pricing ($30/$150 per MTok). It supports the full 1M token context window and 128k max output tokens. Fast mode is ideal for latency-sensitive, interactive workflows such as rapid iteration, live debugging, and real-time agentic tasks where waiting on responses breaks your flow. For cost-sensitive or batch workloads, standard Opus 4.6 offers the same intelligence at lower cost.

Claude Sonnet 4.6 is Anthropic's latest mid-tier model released February 2026, delivering near-flagship Opus-level performance in coding, computer use, and agentic tasks at a fraction of the cost ($3/$15 per million tokens). It features a 1M token context window in beta, scores 79.6% on SWE-bench Verified and 72.5% on OSWorld. Developers preferred it over both Sonnet 4.5 (~70% of the time) and even Opus 4.5 (~59%) in real-world coding tests.

Claude Opus 4.6 is Anthropic's latest model, released February 2026. It is a powerful model for coding and agentic tasks, with a 200K token context window and a 64K output context window.

Claude Opus 4.5 was released in November 2025. It sets the standard for production code, sophisticated agents, and complex enterprise tasks—scoring higher than Anthropic's own engineering candidates on technical tests.

Claude Haiku 4.5 is Anthropic's small, fast model released October 2025, optimized for low latency and cost. Despite being the cheapest option ($1/$5 per million tokens), it matches Sonnet 4 on coding benchmarks (73.3% SWE-bench).

Claude Sonnet 4.5 is Anthropic's most capable model for agents and computer use, released September 2025. It can maintain focus for 30+ hours on complex tasks, supports a 1M token context window (beta), and is described as their "most aligned frontier model."

Claude Opus 4.1 is an August 2025 incremental upgrade to Opus 4 focused on agentic tasks and real-world coding. It improved coding accuracy to 74.5% on SWE-bench with finer-grained refactoring and more precise bug fixes.

Claude Opus 4 is the flagship model from the May 2025 Claude 4 launch, designed for complex long-running tasks. It can work continuously for several hours (7+ hour coding sessions demonstrated) and leads on coding benchmarks at 72.5% SWE-bench.

Claude Sonnet 4 is the May 2025 successor to Sonnet 3.7 with enhanced steerability and coding (72.7% SWE-bench). It excels at following complex instructions precisely and autonomous multi-feature app development with near-zero navigation errors.

Claude 3.7 Sonnet (Thinking Mode) is Claude 3.7 Sonnet with extended thinking enabled by default. It excels at advanced math, competitive programming, and complex problem-solving by showing visible step-by-step reasoning.

Claude 3.7 Sonnet is Anthropic's first hybrid reasoning model, released February 2025. It combines instant responses with an extended thinking mode where users can control the "thinking budget" to balance speed vs. depth.

Claude 3.5 Sonnet balances intelligence and speed, and was the first Claude model to introduce computer use capabilities (screen navigation, clicking, typing) in public beta. It offered performance close to Claude 3 Opus at one-fifth the cost.

Claude 3 Haiku is the fastest and most compact model from the Claude 3 family. It's optimized for near-instant responses and cost-efficiency, ideal for real-time chatbots, content moderation, and high-volume tasks.