How much does the Claude Haiku 4.5 API cost?

On FastMetal, Claude Haiku 4.5 is billed per token in yen: ¥184.8 per 1M input tokens and ¥924 per 1M output tokens, before tax. Usage is drawn from a prepaid balance; there is no subscription or monthly fee.

Can I call Claude Haiku 4.5 with the OpenAI SDK?

Yes. Point base_url at https://api.fastmetal.ai/v1 and pass "anthropic-claude-haiku-4-5" as the model; existing OpenAI-style code works unchanged, including streaming, tool calls and structured output.

What is the context window of Claude Haiku 4.5?

200,000 tokens, shared between the prompt and the response.

How does Claude Haiku 4.5 rank?

#112 on the public arena's Japanese board (ELO 1,357). Ranks move as the leaderboard is updated.

What do I need to try Claude Haiku 4.5?

Create an account and add credit; the model is then available both in the browser chat and over the API. There is no contract or minimum spend.

Back to Models

anthropic/claude-haiku-4-5

Claude Haiku 4.5

Claude Haiku 4.5 is Anthropic’s fastest and most efficient model, delivering near-frontier intelligence at a fraction of the cost and latency of larger Claude models. Matching Claude Sonnet 4’s performance across reasoning, coding, and computer-use tasks, Haiku 4.5 brings frontier-level capability to real-time and high-volume applications. It introduces extended thinking to the Haiku line; enabling controllable reasoning depth, summarized or interleaved thought output, and tool-assisted workflows with full support for coding, bash, web search, and computer-use tools. Scoring >73% on SWE-bench Verified, Haiku 4.5 ranks among the world’s best coding models while maintaining exceptional responsiveness for sub-agents, parallelized execution, and scaled deployment.

10/15/2025

200,000 tokens

#90 Text (spanish)

Input: ¥184.8/M

Output: ¥924/M

Try in Chat Get API Key

Specifications

Modalities

Input

image

text

Output

text

Supported Parameters

include_reasoning

max_tokens

reasoning

response_format

stop

structured_outputs

temperature

tool_choice

tools

top_k

top_p

Max Output Tokens

64,000

Code Examples

curl https://api.fastmetal.ai/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "anthropic-claude-haiku-4-5",
    "messages": [{"role": "user", "content": "Hello!"}]
  }'

How Claude Haiku 4.5 actually answers

Real responses to our standard prompts, recorded on FastMetal.

Count the number of 'r's in 'strawberry'

Count the number of 'r's in 'strawberry'. Explain your reasoning step by step.

# Counting the 'r's in "strawberry" Let me go through each letter in the word "strawberry": 1. **s** - not an 'r' 2. **t** - not an 'r' 3. **r** - this is an 'r' ✓ (1st) 4. **a** - not an 'r' 5. **w** - not an 'r' 6. **b** - not an 'r' 7. **e** - not an 'r' 8. **r** - this is an 'r' ✓ (2nd) 9. **r** - this is an 'r' ✓ (3rd) 10. **y** - not an 'r' **Answer: There are 3 'r's in "strawberry"** The 'r's appear in positions 3, 8, and 9 of the word.

4.1s response228 output tokens

Debug This Error

I'm getting the following error in my Node.js application: TypeError: Cannot read properties of undefined (reading 'map') at UserList (/app/components/UserList.js:12:25) at renderWithHooks (/app/node_modules/rea…

# TypeError: Cannot read properties of undefined (reading 'map') This error occurs because `users` is `undefined` when the component renders. You're trying to call `.map()` on `undefined`, which doesn't have that method. ## Common Causes 1. **Parent component didn't pass the `users` prop** 2. **Async data hasn't loaded yet** 3. **Props passed incorrectly** ## Solutions ### 1. **Provide a Default Value** (Recommended) ```javascript function UserList({ users = [] }) { return ( <ul> {users.map(user => <li key={user.id}>{user.name}</li>)} </ul> ); } ``` ### 2. **Add a Conditional Check** ```javascript function UserList({ users }) { if (!users) { return <p>No users a…

3.9s response671 output tokens

Code Review

Please review the following Python function and suggest improvements for readability, performance, and best practices: def get_data(url, retries=3): import requests import time for i in range(retries):…

# Code Review and Improvements ## Issues Found 1. **Bare `except`** - Catches all exceptions, hiding bugs 2. **Imports inside function** - Should be at module level 3. **Redundant comparison** - `== True` is unnecessary 4. **No logging** - Hard to debug failures 5. **Magic numbers** - Hardcoded timeout and sleep values 6. **Inefficient retries** - Doesn't retry on 200 with parsing errors 7. **Poor variable names** - `r`, `i` are unclear 8. **No type hints** - Reduces code clarity ## Improved Version ```python import logging import requests import time from typing import Optional from requests.exceptions import RequestException logger = logging.getLogger(__name__) def get_data( url:…

5.7s response988 output tokens

Compare these answers side by side with other models →

Frequently asked questions

How much does the Claude Haiku 4.5 API cost?: On FastMetal, Claude Haiku 4.5 is billed per token in yen: ¥184.8 per 1M input tokens and ¥924 per 1M output tokens, before tax. Usage is drawn from a prepaid balance; there is no subscription or monthly fee.
Can I call Claude Haiku 4.5 with the OpenAI SDK?: Yes. Point base_url at https://api.fastmetal.ai/v1 and pass "anthropic-claude-haiku-4-5" as the model; existing OpenAI-style code works unchanged, including streaming, tool calls and structured output.
What is the context window of Claude Haiku 4.5?: 200,000 tokens, shared between the prompt and the response.
How does Claude Haiku 4.5 rank?: #112 on the public arena's Japanese board (ELO 1,357). Ranks move as the leaderboard is updated.
What do I need to try Claude Haiku 4.5?: Create an account and add credit; the model is then available both in the browser chat and over the API. There is no contract or minimum spend.