OpenAI API Integration: Add GPT to Your App
How to integrate the OpenAI API into an existing app: the server-side flow, structured outputs, cost per request from OpenAI's October 2026 prices, rate-limit tiers and data controls.
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Description
Integration OpenAI API integration: adding GPT models to your app or system
An OpenAI API integration adds a model call to software you already run, from your server, never from the browser: your code sends the text and instructions, asks for output in a fixed JSON schema, checks it, and records the tokens used. As of October 2026 OpenAI prices per million tokens, from $0.10 input on GPT-6 Luna to $10 on GPT-6 Astra, so the model you pick sets the running cost.
Discuss an integration Last updated 2 October 2026
What the integration connects
The OpenAI API connects a language model to software you already run: a CRM, a support inbox, an order system, an admin panel. Typical first features are small and specific: classify an incoming enquiry and draft a reply, summarise a long ticket, pull fields out of a supplier's invoice, or answer questions from your own help pages.
The integration is a backend service. It collects the right data from your system, sends it to the model with instructions, checks what comes back, and writes the result where your staff will see it. The browser or mobile app never holds the API key. Choosing which feature to build first, and whether it needs your documents or live records, is covered on add AI to your existing software .
Data flow: classify and draft a reply to an enquiry
New enquiry in your system (website form, email, WhatsApp)
Your server ── remove what the model does not need (IDs, card numbers)
── build request: model, instructions, input text,
output schema {category, urgency, draft_reply}
POST https://api.openai.com/v1/responses
Response ── status complete? refusal? parse JSON against the schema
── read usage: input and output tokens → log cost per request
├── valid ──▶ save category and urgency; put draft in the agent's queue
└── invalid ─▶ retry once, then route to a person unclassified
The draft is a suggestion. A person sends it. That design choice, not the model, is what keeps a wrong answer from reaching a customer.
Field mapping
Your system
Request or response field
Notes
Fixed rules: tone, categories, what not to say
instructions
Kept in your code under version control, not typed per request
The enquiry text and relevant record fields
input
Only the fields the task needs
Allowed categories and output shape
text.format with type: json_schema , strict: true
Structured outputs make the reply follow your schema
Maximum length
max_output_tokens
If it is hit, the response is incomplete and will not match the schema
Whether OpenAI keeps the conversation state
store
Set false when you do not need it
Result
Parsed JSON in the output
Validate again in your own code before saving
Cost tracking
usage input and output token counts
Stored per request, so cost per feature is known
Safety refusals
refusal
Handled as its own outcome, not as an error
Cost per request
Prices below are OpenAI's standard rates per million tokens, read on 2 October 2026. They are billed in US dollars and change often.
Model (OpenAI's description)
Input
Cached input
Output
One request: 1,500 in, 300 out
10,000 such requests
GPT-6 Luna ("most efficient … high-volume tasks")
$0.10
$0.01
$0.50
$0.0003
$3
GPT-6.1 Sol ("near-Astra performance … at a lower cost")
$2.00
$10.00
$0.006
$60
GPT-6 Astra ("most capable … most demanding work")
$1.00
$50.00
$0.03
$300
The arithmetic is tokens × price ÷ 1,000,000, input and output added. Three things move the real figure: how much context you send (a long policy document in every request multiplies input cost), whether repeated context is served at the cached-input rate, and whether the work can wait, since OpenAI's Batch API is priced at half the standard rate. Regional data-residency endpoints add 10% for models released on or after 5 March 2026.
For a classification task, the cheapest model that passes your test set is usually the right one. Testing on a few hundred real enquiries before choosing is cheaper than guessing.
Limits and gotchas
Issue
What OpenAI documents or what happens
What the integration does
Rate limits
Measured in requests and tokens per minute and per day; set per organisation and project, and by model
Queue requests; back off on 429 with a random delay
Usage tiers
Tier 1 needs $5 paid and has a $100 monthly limit; Tier 5 needs $1,000 paid and allows $200,000
Plan the tier before launch; a new account cannot absorb a large launch
Output cut off
max_output_tokens reached; JSON incomplete
Check status ; size the limit to the schema
Wrong but well-formed answers
The schema fixes the shape of the answer, not its truth
Validate values against your own data; keep a person in the loop for anything sent out
Personal data
Sent to a third party
Strip what is not needed; record it in your privacy notice
Model retirement
Older models stay on the price list for a while, then go
Keep the model name in configuration and a test set to re-run on a new model
Key leakage
A key in a mobile app or web page can be copied
Calls only from your server; separate keys per project
When answers are wrong because the model lacks your information, the fix is usually retrieval over your documents, not a bigger model; see what RAG is and RAG development . If a deployed assistant is already misbehaving, read AI chatbot giving wrong answers.
What WavX builds
WavX builds the server-side service around the model: data preparation and redaction, prompt and schema in version control, a test set from your own records, validation of every response, retries and queueing, per-request cost logging, and a screen where staff review what the AI produced. The same service can call Anthropic's models instead; see Claude API integration and the comparison of OpenAI, Claude and Gemini APIs.
Effort band
The AI cost calculator prices an AI feature in an existing app from a ₹2,50,000 base, a planning range of ₹2,12,500 to ₹3,12,500 when no custom data is needed, and higher when it works on your documents or live systems. These are planning ranges, not quotes. Model usage is paid to OpenAI separately, on your own account.
When not to integrate the API
If staff only need help writing emails or summarising documents, ChatGPT subscriptions for those staff are cheaper than any integration. If the task is a fixed rule (route by pincode, flag orders over a value), ordinary code is cheaper, faster and never wrong in new ways. Integrate the API when the task needs language understanding, runs inside your system, and is frequent enough that copying text into a chat window costs real staff time.
Frequently asked questions
Is the OpenAI API the same as ChatGPT?
No. ChatGPT is OpenAI's app for people. The API is a paid service your software calls, billed per token, with its own models, limits and data terms. Integrating 'ChatGPT' into a product means calling the API from your server.
Will OpenAI train its models on our customers' data?
OpenAI's data controls page says data sent to the API is not used to train or improve its models unless you opt in. Abuse-monitoring logs are kept for up to 30 days unless the law requires longer, and some endpoints are eligible for Zero Data Retention on approval. Your own privacy notice and consent still need to cover sending the data.
Can the data stay in India?
Partly. OpenAI lists India among its data residency options, through an in.api.openai.com domain, but as of October 2026 it offers regional storage there, not regional processing. Regional endpoints carry a 10% price uplift for models released on or after 5 March 2026.
How much will the API cost us each month?
Multiply requests by tokens per request by the model's price. A request with 1,500 input and 300 output tokens costs about $0.0003 on GPT-6 Luna and $0.006 on GPT-6.1 Sol at October 2026 prices. We measure real token counts on your data before you commit to a model.
Sources
OpenAI API docs: Pricing · read 2 October 2026
OpenAI API docs: Models · read 2 October 2026
OpenAI API docs: Rate limits · read 2 October 2026
OpenAI API docs: Data controls (your data) · read 2 October 2026
OpenAI API docs: Structured outputs · read 2 October 2026
Related
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