Compare

Gemini 2.5 Pro vs GPT-5.5 Pro

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.

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Gemini 2.5 Pro
google/gemini-2.5-pro
GPT-5.5 Pro
openai/gpt-5.5-pro
Provider
Google
OpenAI
Family
GPT-5
Modality
text
text
Context window
1,000,000 tok
1,000,000 tok
Max output
65,536 tok
16,384 tok
Released
2026-05-22
2026-05-22
License
Proprietary
Proprietary
Input price
$1.25 /1M
$30.00 /1M
Output price
$10.00 /1M
$180.00 /1M
Tools
yes
Streaming
yes
yes
Vision
JSON mode
yes
Reasoning
yes
Prompt caching
Batch API
Try it
Open in playground →
Open in playground →
Gemini 2.5 Pro
google/gemini-2.5-pro
Full spec →

Google's most capable Gemini 2.5 model with strong reasoning, thinking support, and a 1M token context window.

Strengths
  • General-purpose chat
  • Long context
  • Tool use
Use cases
ChatbotsContent generationAgentic workflows
GPT-5.5 Pro
openai/gpt-5.5-pro
Full spec →

GPT-5.5 pro uses OpenAI's Responses API with built-in tools, improved reasoning, and stateful context management.

Strengths
  • General-purpose chat
  • Long context
  • Tool use
Use cases
ChatbotsContent generationAgentic workflows

Compare with another

Claude Opus 4.8 vs Gemini 2.5 Pro
anthropic/claude-opus-4.8 · google/gemini-2.5-pro
Claude Opus 4.8 vs GPT-5.5 Pro
anthropic/claude-opus-4.8 · openai/gpt-5.5-pro
Claude Sonnet 4.6 vs Gemini 2.5 Pro
anthropic/claude-sonnet-4.6 · google/gemini-2.5-pro
Claude Sonnet 4.6 vs GPT-5.5 Pro
anthropic/claude-sonnet-4.6 · openai/gpt-5.5-pro
Grok 4.20 Multi-Agent vs Gemini 2.5 Pro
xai/grok-4.20-multi-agent-0309 · google/gemini-2.5-pro
Grok 4.20 Multi-Agent vs GPT-5.5 Pro
xai/grok-4.20-multi-agent-0309 · openai/gpt-5.5-pro
GPT-5.4 vs Gemini 2.5 Pro
openai/gpt-5.4 · google/gemini-2.5-pro
GPT-5.4 vs GPT-5.5 Pro
openai/gpt-5.4 · openai/gpt-5.5-pro
Gemini 2.5 Pro vs Gemini 3.1 Pro
google/gemini-2.5-pro · google/gemini-3.1-pro
SWITCH BETWEEN THEM

One key, all 2, one line different.

from openai import OpenAI

client = OpenAI(
    base_url="https://api.aigateway.sh/v1",
    api_key="sk-aig-...",
)

# Gemini 2.5 Pro
client.chat.completions.create(
    model="google/gemini-2.5-pro",
    messages=[{"role":"user","content":"hello"}],
)

# GPT-5.5 Pro
client.chat.completions.create(
    model="openai/gpt-5.5-pro",
    messages=[{"role":"user","content":"hello"}],
)
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