Pricing per million tokens, context window, capabilities — pulled from each provider's public docs. All 2 are available via the same AIgateway OpenAI-compatible endpoint; flip the model string to switch.
GPT-5.5 pro uses OpenAI's Responses API with built-in tools, improved reasoning, and stateful context management.
GLM-5.3 is Z.ai's flagship agentic coding model, pairing a 1M-token context window with reasoning, function calling, and structured outputs to power multi-step, tool-driven development workflows.
from openai import OpenAI
client = OpenAI(
base_url="https://api.aigateway.sh/v1",
api_key="sk-aig-...",
)
# GPT-5.5 Pro
client.chat.completions.create(
model="openai/gpt-5.5-pro",
messages=[{"role":"user","content":"hello"}],
)
# Glm-5.3
client.chat.completions.create(
model="zai-org/glm-5.3",
messages=[{"role":"user","content":"hello"}],
)