Claude Haiku 4.5
Anthropic's fastest and cheapest 4.x model. Strong vision and tool use at ultra-low latency, ideal for high-concurrency workloads.
Claude Haiku 4.5 is multimodal AI model from Anthropic, priced at €0.001 per 1M input tokens with a 200K tokens context window.
About this model
0.7
Pricing
API Integration
Use our OpenAI-compatible API to integrate Claude Haiku 4.5 into your application.
npm install railwailimport railwail from "railwail";
const rw = railwail("YOUR_API_KEY");
// Simple — just pass a string
const reply = await rw.run("claude-haiku-4-5", "Hello! What can you do?");
console.log(reply);
// With message history
const reply2 = await rw.run("claude-haiku-4-5", [
{ role: "system", content: "You are a helpful assistant." },
{ role: "user", content: "Explain quantum computing simply." },
]);
console.log(reply2);
// Full response with usage info
const res = await rw.chat("claude-haiku-4-5", [
{ role: "user", content: "Hello!" },
], { temperature: 0.7, max_tokens: 500 });
console.log(res.choices[0].message.content);
console.log(res.usage);Deep dive — Anthropic's Claude Haiku 4.5
Anthropic was founded in 2021 by Dario and Daniela Amodei. The Claude model family launched in March 2023 with Haiku as the lightweight tier optimized for low latency and cost. Successive Haiku generations have steadily closed the gap to Sonnet: Haiku 3 (March 2024), Haiku 3.5 (October 2024), Haiku 4 (May 2025) and Haiku 4.5 (late 2025/early 2026). Anthropic is structured as a Public Benefit Corporation focused on AI safety, with total funding exceeding $20 billion and a 2026 valuation above $150 billion.
Visit Anthropic →Claude Haiku 4.5 is the fastest and cheapest model in the Claude 4.x family. Architecturally it is a smaller decoder-only Transformer distilled from the Sonnet/Opus 4 training stack, optimized aggressively for inference latency and throughput while retaining the full Claude feature set (vision, extended thinking, tool use). It was trained on the same multi-trillion-token curated corpus as its larger siblings with a knowledge cutoff in early 2026. Post-training combined RLHF, Constitutional AI, RLAIF and distillation from larger teacher models. Despite its small size, Haiku 4.5 supports the same 200K context window and tool-use API as Sonnet 4.6 and Opus 4.7, making it a drop-in cheaper option for high-concurrency workloads.
- Parameters
- Undisclosed (estimated tens of billions of parameters)
- Context
- 200K tokens
- Lowest p50 latency in the Claude 4.x family
- 200K token context window matching the larger Claude models
- Vision input for images, PDFs and screenshots
- Native tool use with parallel tool calling
- Optional extended thinking mode for harder reasoning tasks
- Sonnet-class reliability at one-third the cost
- Strong instruction following and structured JSON output
- Constitutional-AI alignment with low refusal rate
- Available via Anthropic API, Bedrock and Vertex AI
- Multilingual fluency across 20+ languages
- Best for: high-volume agents, real-time chat, classification, simple coding subagents, consumer apps.
Pretrained on the same curated multi-trillion-token mixture used by Sonnet and Opus 4.x. Post-training includes distillation from larger Anthropic models alongside RLHF, Constitutional AI and RLAIF. Knowledge cutoff in early 2026.
License: Proprietary commercial license via Anthropic API, Amazon Bedrock and Google Vertex AI.
Known limitations
- Below Sonnet 4.6 on hard reasoning and agentic coding benchmarks
- No native audio or video input
- Knowledge cutoff in early 2026
- Less depth on niche or long-tail topics than larger models
- No fine-tuning available to external customers
Frequently asked questions
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