Claude Haiku 3.5 vs Claude Haiku 4.5: Which AI Model Should You Choose?

Pricing, context windows, latency, capabilities, and a one-line code switch β€” everything you need to pick the right model.

Anthropic
Text & Chat
vs
Anthropic
Multimodal
Verdict

These models serve different use cases (Text & Chat vs Multimodal) β€” pick the one whose category matches your workload.

Side-by-side specs

SpecClaude Haiku 3.5Claude Haiku 4.5
ProviderAnthropicAnthropic
CategoryText & ChatMultimodal
Input cost / 1M tokensn/a$1.20
Output cost / 1M tokensn/a$6.00
Context window200K tokens200K tokens
Max output tokens8,19264,000
Avg. latency1.0sβ€”
Featuredβ€”β€”
Newβ€”Yes
Capabilitiesβ€”
text
image

Pricing example

A typical chat workload of 100,000 input tokens plus 50,000 output tokens.

Claude Haiku 3.5
n/a

100K in Γ— n/a + 50K out Γ— n/a

Claude Haiku 4.5
$0.42

100K in Γ— $1.20 + 50K out Γ— $6.00

Switch in one line

Both models live behind Railwail's OpenAI-compatible endpoint. Replace the model string and you are done.

JavaScript / TypeScript
import OpenAI from "openai";

const client = new OpenAI({
  apiKey: process.env.RAILWAIL_API_KEY,
  baseURL: "https://railwail.com/v1",
});

// Before β€” using Claude Haiku 3.5
let r = await client.chat.completions.create({
  model: "claude-3-5-haiku-20241022",
  messages: [{ role: "user", content: "Hello" }],
});

// After β€” switched to Claude Haiku 4.5
r = await client.chat.completions.create({
  model: "claude-haiku-4-5-20251001",
  messages: [{ role: "user", content: "Hello" }],
});
Python
from openai import OpenAI

client = OpenAI(
    api_key=os.environ["RAILWAIL_API_KEY"],
    base_url="https://railwail.com/v1",
)

# Before β€” using Claude Haiku 3.5
r = client.chat.completions.create(
    model="claude-3-5-haiku-20241022",
    messages=[{"role": "user", "content": "Hello"}],
)

# After β€” switched to Claude Haiku 4.5
r = client.chat.completions.create(
    model="claude-haiku-4-5-20251001",
    messages=[{"role": "user", "content": "Hello"}],
)
cURL
# Before β€” using Claude Haiku 3.5
curl https://railwail.com/v1/chat/completions \
  -H "Authorization: Bearer $RAILWAIL_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-3-5-haiku-20241022",
    "messages": [{"role": "user", "content": "Hello"}]
  }'

# After β€” switched to Claude Haiku 4.5
curl https://railwail.com/v1/chat/completions \
  -H "Authorization: Bearer $RAILWAIL_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-haiku-4-5-20251001",
    "messages": [{"role": "user", "content": "Hello"}]
  }'

Which one wins for...

Quick verdicts derived from public specs. Always validate on your own workload.

Coding
Claude Haiku 3.5

Higher coding category match or larger context wins.

Writing
Claude Haiku 3.5

Bigger context window helps maintain long-form coherence.

Long documents
Claude Haiku 3.5

The larger context window is the deciding factor.

Vision
Claude Haiku 4.5

Multimodal/vision support is required for image inputs.

Real-time chat
Claude Haiku 3.5

Lower average latency wins for interactive UX.

Cost-sensitive
Tie

The model with the lower input-token price wins.

Frequently asked questions

Which is cheaper, Claude Haiku 3.5 or Claude Haiku 4.5?
Claude Haiku 3.5 and Claude Haiku 4.5 cannot be compared on per-token price: at least one of them has no per-token price listed (it is priced per run or not yet priced). See each model page for its current price.
Which has more context, Claude Haiku 3.5 or Claude Haiku 4.5?
Claude Haiku 3.5 and Claude Haiku 4.5 have similar context windows (200K tokens vs 200K tokens).
Is Claude Haiku 3.5 better than Claude Haiku 4.5 for coding?
For coding-heavy workloads we lean toward Claude Haiku 3.5 on this comparison β€” it scores higher on the relevant heuristics (category, tags, or context window). Both models are usable for code via Railwail's OpenAI-compatible endpoint, so the safest path is to A/B test on your own prompts.
Can I use both Claude Haiku 3.5 and Claude Haiku 4.5 via Railwail?
Yes. Both Claude Haiku 3.5 and Claude Haiku 4.5 are accessible through a single Railwail API key and the OpenAI-compatible /v1/chat/completions endpoint. You only change the "model" parameter to switch between them β€” no SDK swap, no separate billing.
How do I switch from Claude Haiku 3.5 to Claude Haiku 4.5?
Replace the model identifier "claude-3-5-haiku-20241022" with "claude-haiku-4-5-20251001" in your request payload. Everything else β€” API key, base URL, request shape β€” stays the same. See the code example on this page for the exact one-line change.

Try Claude Haiku 3.5 and Claude Haiku 4.5 side by side

One API key, one endpoint, both models. Start free β€” no credit card required.