o3-pro
API guide
Chat completion
Call openai/o3-pro through TheRouter's standard chat completions endpoint. The reasoning chain runs server-side and the model returns the final answer in a single message. Hard problems can take minutes β raise your client timeout to at least 600s.
curl https://api.therouter.ai/v1/chat/completions \
-H "Authorization: Bearer $THEROUTER_API_KEY" \
-H "Content-Type: application/json" \
--max-time 900 \
-d '{
"model": "openai/o3-pro",
"messages": [
{"role": "user", "content": "Prove that for every prime p > 2, p^2 - 1 is divisible by 24. Show every step."}
]
}'Reasoning effort
o3-pro accepts a reasoning parameter for explicit control. The model is tuned for high-effort by design β lower settings reduce compute used per request and may degrade quality on hard problems. Pass reasoning.effort='high' for the full o3-pro experience.
curl https://api.therouter.ai/v1/chat/completions \
-H "Authorization: Bearer $THEROUTER_API_KEY" \
-H "Content-Type: application/json" \
--max-time 900 \
-d '{
"model": "openai/o3-pro",
"reasoning": { "effort": "high" },
"messages": [
{"role": "user", "content": "Diagnose why this Kubernetes pod is OOMKilled even though resources.limits.memory is set to 4Gi."}
]
}'Tool calling
o3-pro supports function calling and ChatGPT-style tools (web search, file analysis, Python). Use it for agent loops where each step is genuinely hard β e.g. multi-document research, complex code refactors, or financial / scientific analysis where wrong tool choices are costly.
curl https://api.therouter.ai/v1/chat/completions \
-H "Authorization: Bearer $THEROUTER_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "openai/o3-pro",
"messages": [{"role": "user", "content": "Compare last quarter revenue growth for Apple, Microsoft and Nvidia and rank them."}],
"tools": [{
"type": "function",
"function": {
"name": "get_earnings",
"description": "Fetch most recent reported revenue for a stock ticker",
"parameters": {
"type": "object",
"properties": { "ticker": {"type": "string"} },
"required": ["ticker"]
}
}
}],
"parallel_tool_calls": true
}'Vision
o3-pro accepts images alongside text. Useful for reading complex diagrams, dense charts, math/proof scans, or screenshots of legacy code where the structure is essential to understanding.
curl https://api.therouter.ai/v1/chat/completions \
-H "Authorization: Bearer $THEROUTER_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "openai/o3-pro",
"messages": [{"role": "user", "content": [
{"type": "text", "text": "Read this circuit schematic and explain how the feedback loop stabilises gain."},
{"type": "image_url", "image_url": {"url": "https://therouter.ai/assets/vision-sample.png"}}
]}]
}'Fact ledger β every claim on this page traces here
| source | URL | retrieved | |
|---|---|---|---|
| Release date | techcrunch.com β | 2026-06-01 | verified |
| Knowledge cutoff | llm-stats.com β | 2026-06-01 | verified |
| Reasoning mode | platform.openai.com β | 2026-06-01 | verified |
| Native API surface | platform.openai.com β | 2026-06-01 | verified |
| Tool support | techcrunch.com β | 2026-06-01 | verified |
| License | β | β | verified |
| AIME 2024 | r/singularity launch-day benchmarks thread β | 2026-06-01 | to verify |
| GPQA Diamond | techcrunch.com β | 2026-06-01 | to verify |
| 4-for-4 reliability (AIME 2024) | OpenAI launch chart summary β | 2026-06-01 | to verify |
| 4-for-4 reliability (GPQA Diamond) | OpenAI launch chart summary β | 2026-06-01 | to verify |
| GPT-5 Pro launched at OpenAI DevDay 2025 | openai.com β | 2026-06-01 | verified |
| o3-pro released, replacing o1-pro | techcrunch.com β | 2026-06-01 | verified |
| o3 and o4-mini launched, o3-pro preview announced | openai.com β | 2026-06-01 | verified |
| How long do o3-pro responses take? | platform.openai.com β | 2026-06-01 | to verify |