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Google
Gemini 3.1 PRO Preview Customtools
Gemini 3.1 PRO Preview Customtools is a reasoning model by Google with vision, function calling, web search, prompt caching, structured output — designed for complex, multi-step problem solving where accuracy matters more than speed. It supports a 1M token context window with up to 66K tokens of output. Priced at $2 per million input tokens and $12 per million output tokens. Access Gemini 3.1 PRO Preview Customtools through Inworld Router with OpenAI SDK compatibility, built-in failover, and intelligent routing across providers.
→Function CallingWeb SearchReasoningPrompt CachingResponse SchemaVisionreasoningCapabilityresponseFormatCapability
Step 1 — Create Router
curl --location 'https://api.inworld.ai/router/v1/routers' \
--header 'Authorization: Basic <your-api-key>' \
--header 'Content-Type: application/json' \
--data '{
"name": "compare-frontier-models",
"defaultRoute": {
"route_id": "default",
"variants": [
{
"variant": {
"variant_id": "google-ai-studio/gemini-3.1-pro-preview-customtools-a",
"model_id": "google-ai-studio/gemini-3.1-pro-preview-customtools"
},
"weight": 33
},
{
"variant": {
"variant_id": "inworld/models/gemma-4-31b-it-b",
"model_id": "inworld/models/gemma-4-31b-it"
},
"weight": 33
},
{
"variant": {
"variant_id": "inworld/models/gemma-4-26b-a4b-it-c",
"model_id": "inworld/models/gemma-4-26b-a4b-it"
},
"weight": 34
}
]
}
}'Step 2 — Chat Completion
curl --location 'https://api.inworld.ai/v1/chat/completions' \
--header 'Authorization: Basic <your-api-key>' \
--header 'Content-Type: application/json' \
--data '{
"model": "inworld/compare-frontier-models",
"messages": [{"role": "user", "content": "Hello!"}]
}'Gemini 3.1 PRO Preview Customtools pricing and providers
Access Gemini 3.1 PRO Preview Customtools through Google AI Studio via Inworld Router or Realtime API. By using the AI provider(s) below you acknowledge you reviewed and agree to their terms listed in the Legal section under the AI provider's name.
| Capabilities | Input modalities | Output modalities | |||||||
|---|---|---|---|---|---|---|---|---|---|
 Google AI Studio | $2.00 | $12.00 | $0.20 | $2.00 | 1M | 65.5K | +5 |
Prices in USD per 1M tokens.
Other Google models available through Inworld
Compare Gemini 3.1 PRO Preview Customtools with other Google models available through Inworld Router or Realtime API.
| Provider | Capabilities | Input modalities | Output modalities | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Gemma 4 31b ItPopular | $0.13 | $0.38 | $0.065 | — | 262.1K | — | +2 | |||
| Gemma 4 26b A4b ItPopular | $0.07 | $0.34 | $0.035 | — | 262.1K | — | +2 | |||
| Gemini 2.5 Flash Lite | $0.10 | $0.40 | $0.01 | $0.10 | 1M | 65.5K | +5 | |||
| Gemini 3.1 Flash Lite | $0.25 | $1.50 | $0.025 | $0.25 | 1M | 65.5K | +5 | |||
| Gemini 3.8 Flash | $0.75 | $3.75 | $0.075 | $0.75 | 1M | 65.5K | +5 | |||
| Gemini 3.7 Flash | $0.75 | $3.75 | $0.075 | $0.75 | 1M | 65.5K | +5 | |||
| Gemini 3.6 Flash | $0.75 | $3.75 | $0.075 | $0.75 | 1M | 65.5K | +5 | |||
| Gemini 3.5 Flash | $1.50 | $9.00 | $0.15 | $1.50 | 1M | 65.5K | +5 | |||
| Gemini 3.5 Flash Lite | $0.30 | $2.50 | $0.03 | $0.30 | 1M | 65.5K | +5 | |||
| Gemini 3.1 Flash Image | $0.50 | $60.00 | — | — | 65.5K | 32.8K | +2 | |||
| Gemini 3.1 Flash Lite Image | $0.25 | $30.00 | — | — | 65.5K | 65.5K | ||||
| Gemini 3.1 PRO Preview | $2.00 | $12.00 | $0.20 | $2.00 | 1M | 65.5K | +5 | |||
| Gemini 3 Flash Preview | $0.50 | $3.00 | $0.05 | $0.50 | 1M | 65.5K | +5 | |||
| Gemini 2.5 Flash | $0.30 | $2.50 | $0.03 | $0.30 | 1M | 65.5K | +5 | |||
| Gemini 2.5 Flash Lite | $0.10 | $0.40 | $0.01 | $0.10 | 1M | 65.5K | +5 | |||
| Gemini 2.5 PRO | $1.25 | $10.00 | $0.125 | $1.25 | 1M | 65.5K | +5 | |||
| Gemma 4 31B It Turbo | $0.09 | $0.34 | $0.05 | — | 262.1K | — | +3 |
Prices in USD per 1M tokens.
Start building with Gemini 3.1 PRO Preview Customtools
Access Gemini 3.1 PRO Preview Customtools and every other model through Inworld Router or Realtime API. Create your free account and start routing in minutes.