Pricing, context window, capabilities, and release date — pulled from each provider's public docs. Both are available via the same AIgateway OpenAI-compatible endpoint; flip the model string to switch.
Both models stream in parallel through your own AIgateway key. Tokens, latency, and cost update as they arrive.
| Claude Sonnet 4 anthropic/claude-sonnet-4 | Claude Sonnet 4.5 anthropic/claude-sonnet-4.5 | |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Family | Claude 4 | Claude 4 |
| Modality | text | text |
| Context window | 200,000 tok | 200,000 tok |
| Max output | 16,000 tok | 8,192 tok |
| Released | 2026-04-13 | 2026-04-13 |
| Input price | $3.00 /1M | $3.00 /1M |
| Output price | $15.00 /1M | $15.00 /1M |
| Cache read | — | — |
| Tools | yes | yes |
| Streaming | yes | yes |
| Vision | — | — |
| JSON mode | yes | yes |
| Reasoning | yes | yes |
| Prompt caching | — | — |
Claude Sonnet 4 delivers superior coding and reasoning while responding more precisely to instructions, a significant upgrade over previous versions.
Claude Sonnet 4.5 is the best coding model to date, with significant improvements across the entire development lifecycle.
# pip install aigateway-py openai
# aigateway-py: sub-accounts, evals, replays, jobs, webhook verify.
# openai SDK: chat/embeddings/images/audio — drop-in compat per our SDK's own guidance.
from openai import OpenAI
client = OpenAI(
base_url="https://api.aigateway.sh/v1",
api_key="sk-aig-...",
)
# Try Claude Sonnet 4
client.chat.completions.create(
model="anthropic/claude-sonnet-4",
messages=[{"role":"user","content":"hello"}],
)
# Try Claude Sonnet 4.5 — same client, same key
client.chat.completions.create(
model="anthropic/claude-sonnet-4.5",
messages=[{"role":"user","content":"hello"}],
)