AnthropicText / ChatClaude Haiku 4.5 API: Anthropic on Vertex (Claude)'s chat / LLM model, one key away
Claude Haiku 4.5 via the ApexApi gateway
Claude Haiku 4.5 is a chat / LLM model from Anthropic on Vertex (Claude). Call it through ApexApi's unified, OpenAI-compatible API with one `ak-` key, alongside every other model in the catalog. It supports a 200,000-token context window, tool / function calling, image (vision) input, and streaming responses. Pricing is $1.20 input and $6.00 output per 1M tokens, billed pay-per-use from your credit balance with no subscription.
Claude Haiku 4.5 is served through ApexApi's unified, OpenAI-compatible API. One key, one format, with smart routing and automatic failover. Provider: Anthropic on Vertex (Claude).
Why Claude Haiku 4.5
200,000-token context
Reason over long documents, codebases, and multi-turn history in a single request.
Tool & function calling
Structured outputs and tool orchestration for agentic and automation workloads.
Vision input
Send images alongside text for document, UI, and visual-understanding tasks.
Specifications
- Modality
- chat
- Context window
- 200K tokens
- Max output
- 8.2K tokens
- Streaming
- Yes
- Tool / function calling
- Yes
- Vision input
- Yes
Claude Haiku 4.5 pricing
Pay-per-use. No subscription, no minimums. Buy credits and pay only for what you call. Transparent, per-call pricing across every model.
Getting started with Claude Haiku 4.5
OpenAI-compatible. Point your client at ApexApi, swap your key, and call it. No new SDK to learn.
from openai import OpenAI
client = OpenAI(
base_url="https://api.apexapi.dev/v1",
api_key="<YOUR_APEXAPI_KEY>",
)
response = client.chat.completions.create(
model="anthropic/claude-haiku-4.5",
messages=[{"role": "user", "content": "Hello!"}],
)
print(response.choices[0].message.content)Claude Haiku 4.5 use cases
What teams build with Claude Haiku 4.5 on ApexApi.
Agents & automation
Tool-using agents that orchestrate multi-step workflows and call APIs.
Coding assistants
Code generation, refactoring, reviews, and multi-file reasoning.
RAG & knowledge apps
Summarization and long-document Q&A grounded in your own data.
Claude Haiku 4.5 vs other models
How it compares, and on ApexApi you can switch between any of them with a single string change, same key, same endpoint.
Claude Haiku 4.5 vs Claude Opus 4.7
Compare Claude Haiku 4.5 against this model on price, capabilities, and latency. A/B them with a single key on ApexApi.
Learn more about Claude Opus 4.7 API →Claude Haiku 4.5 vs GPT-5.5
Compare Claude Haiku 4.5 against this model on price, capabilities, and latency. A/B them with a single key on ApexApi.
Learn more about GPT-5.5 API →Claude Haiku 4.5 vs Gemini 3.1 Pro Preview
Compare Claude Haiku 4.5 against this model on price, capabilities, and latency. A/B them with a single key on ApexApi.
Learn more about Gemini 3.1 Pro Preview API →Why build on ApexApi
One API, every model
OpenAI-compatible. Swap the base URL and key, keep your code. Call 14+ providers and hundreds of models through a single integration.
Smart routing & failover
Per-model provider chains with automatic failover. If one provider degrades, requests route to the next. Your app stays up.
Pay-per-use, no lock-in
Buy credits, pay only for what you call. No subscriptions, no minimums. Switch models anytime with a single string change.
Claude Haiku 4.5 API: FAQ
How do I use the Claude Haiku 4.5 API?
Create an ApexApi key, then point your client at https://api.apexapi.dev/v1 and use the model slug. Send a request to /v1/chat/completions with the model slug. The API is OpenAI-compatible, so most OpenAI SDKs work by changing the base URL and key.
Is the Claude Haiku 4.5 API OpenAI-compatible?
Yes. ApexApi exposes Claude Haiku 4.5 through the same OpenAI-compatible interface used across the whole catalog. Swap the base URL and API key and keep your existing code.
How much does Claude Haiku 4.5 cost on ApexApi?
Pay-per-use. See the live price in the Pricing section above. There's no subscription or minimum; you buy credits and pay only for what you call.
Can I switch from Claude Haiku 4.5 to another model later?
Yes. Change a single string (the model slug) to call any other model in the catalog through the same endpoint and key. No re-integration.
Ready to build with Claude Haiku 4.5?
One API key. Every major AI model. Pay only for what you use.
Get your API key, free to start