Short answer
GPT-5.5 is available through APIVAI at $0.77 per million input tokens and $4.56 per million output tokens as of 2026-10-07, 85% below OpenAI's official list price of $5.00 / $30.00. Use the model ID gpt-5.5 with an APIVAI key in the OpenAI format at https://api.apivai.com/v1 (Chat Completions and the Responses API). Billing is pay-as-you-go from a prepaid balance, from $10, with no subscription.
GPT-5.5 API pricing
| Per 1M tokens | APIVAI | Official list price |
|---|---|---|
| Input | $0.77 | $5.00 |
| Output | $4.56 | $30.00 |
Prompt caching: cache writes cost $0.0768 and cache reads $0.0768 per million tokens. Context window: 1M tokens. Prices are checked against the price list every 6 hours; see all model prices.
How much does GPT-5.5 cost per request?
Each request is billed for its input and output tokens. Coding agents resend the conversation and files with every step, so their requests are much larger than a chat message.
| Example | Input / output tokens | APIVAI | Official price |
|---|---|---|---|
| One chat message | 2,000 / 500 each | $0.00382 | $0.025 |
| One coding-agent step | 30,000 / 1,500 each | $0.0299 | $0.195 |
| 1,000 chat messages | 2,000 / 500 each | $3.82 | $25.00 |
| A month of agent use (100 steps a day, 22 days) | 30,000 / 1,500 each | $65.87 | $429 |
Thinking is on by default and thinking tokens are billed as output, so the real output count can be higher than the text you see.
How do you call GPT-5.5?
cURL (OpenAI format)
curl https://api.apivai.com/v1/chat/completions \
-H "Authorization: Bearer $APIVAI_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "gpt-5.5",
"max_tokens": 4096,
"messages": [{"role": "user", "content": "Hello!"}]
}'Python (OpenAI SDK)
from openai import OpenAI
client = OpenAI(api_key="YOUR_APIVAI_API_KEY", base_url="https://api.apivai.com/v1")
resp = client.chat.completions.create(
model="gpt-5.5",
max_tokens=4096,
messages=[{"role": "user", "content": "Hello!"}],
)
print(resp.choices[0].message.content)Codex CLI
# ~/.codex/config.toml model = "gpt-5.5" model_provider = "apivai" [model_providers.apivai] name = "APIVAI" base_url = "https://api.apivai.com/v1" env_key = "OPENAI_API_KEY" wire_api = "responses"
Codex uses the Responses API, which APIVAI supports. More tools: API documentation and OpenAI-compatible API.
Other OpenAI models
| Model | Input / output per 1M | Below official price |
|---|---|---|
| GPT-6 Astra | $1.52 / $7.60 | 85% |
| GPT-5.6 Sol | $0.61 / $3.65 | 85% |
| GPT-5.6 Terra | $0.30 / $1.82 | 85% |
| GPT-6.1 Sol | $0.30 / $1.52 | 85% |
| GPT-6 Sol | $0.30 / $1.52 | 85% |
| GPT-5.6 Luna | $0.0304 / $0.18 | 85% |
| GPT-6 Luna | $0.0144 / $0.0768 | 86% |
Setup guides
FAQ
Is this the same GPT-5.5 model?
Yes. Requests with the model ID gpt-5.5 are answered by GPT-5.5; only the price and the way you pay differ.
What is the model ID for GPT-5.5?
gpt-5.5. The list of models changes over time, so check GET https://api.apivai.com/v1/models with your key before hard-coding a name.
Which tools can use GPT-5.5?
Codex CLI and any OpenAI-compatible tool or SDK (Cursor, Cline, Continue, Aider and others) through https://api.apivai.com/v1.
How is GPT-5.5 billed?
Per token, from a prepaid balance: $0.77 per million input tokens and $4.56 per million output tokens, with thinking tokens counted as output. The minimum top-up is $10 and there is no subscription.
How many requests can I send?
Each key allows 60 requests per minute by default; support can raise the limit.
Create an account, top up from $10 and use gpt-5.5 with your key.