OpenAI API

API for GPT models: text, images, speech, embeddings and agents.

Works with AI agents:llms.txtBuilt into Lovable, Replit
Ask your AI about this, with this page as the source:ChatGPT ↗Claude ↗Perplexity ↗

The OpenAI API gives your backend HTTP access to OpenAI's models: text and code generation, reasoning, image generation and editing, speech-to-text, text-to-speech, realtime voice, embeddings and moderation. It is how you put GPT models inside your own product, billed to your organization rather than to a ChatGPT subscription.

You authenticate with a secret API key that belongs to a project inside an organization; rate limits, spend limits and data settings are set at those two levels. OpenAI recommends the Responses API for new work: one endpoint that can keep conversation state on OpenAI's side (store) and call built-in tools such as web search, file search, code interpreter, computer use and remote MCP servers. The older Chat Completions API is still supported. Official SDKs cover TypeScript/JavaScript, Python, .NET, Java, Go and Ruby, plus an Agents SDK for TypeScript and Python.

For a small team the useful pieces are structured outputs and function calling, a Batch API for offline jobs, prompt caching, fine-tuning, evals, and per-project spend limits and alerts. It runs only as OpenAI's hosted service; eligible customers can pin projects to regions such as the US or EU, and the models are also sold through Microsoft Azure.

The main limit is that the models are closed: you can't self-host them, and your traffic depends on OpenAI's terms, rate-limit tiers and model deprecation schedule.

Where it fits

How OpenAI API itself is built

5 tools, from its own code, website and Product Hunt page.

Who uses it

734 makers' products, each linked to the source that shows it, and 481 open-source projects that declare it in their code.

The maker says so 660Subprocessor list 96Declared in code 488How evidence is collected →
omiOpen-source AI wearable with mobile and desktop apps that records conversations and meet…

“Shoutout to OpenAI for powering our brains with GPT—couldn't build magic without you.”

LLM APIMaker says so +2 · source ↗
giselleGiselle is an open-source tool for building and running AI workflows in a visual node ed…

“OpenAI's GPT models power a wide range of Giselle's AI workflows. From GPT-5 nano for quick, cost-effective tasks on our free tier, to GPT-5 mini for balanced everyday use, GPT-5 and GPT-5.1 Codex for complex reasoning and coding agents, and GPT-5.2 for the most demanding challenges — we leverage the full GPT family. The Reasoning Effort parameter lets users fine-tune the balance between speed and depth, while Web Search keeps workflows grounded in real-time information. Thank you for building such a versatile AI platform!”

LLM APIMaker says so +1 · source ↗
LangfuseOpen-source LLM engineering platform for tracing, evaluation, prompt management and expe…

“OpenAI function calling powers the new evaluation service. Reliability out of the box without any weird outputs!”

LLM APIMaker says so +1 · source ↗
PlaneOpen-source project management app with issues, cycles, and modules as a self-hostable a…

“We use OpenAI to power Plane AI — enabling teams to chat with their projects, write PRDs, dedupe issues, and get instant insights. It’s the brain behind everything smart inside Plane.”

LLM APIMaker says so +1 · source ↗
SupabasePostgres-based backend: database, auth, storage, realtime and edge functions in one proj…

“Supabase AI Assistant leverages the incredible capabilities of OpenAI’s models to deliver intelligent, context-aware assistance for developers.”

LLM APIMaker says so +1 · source ↗
SlashyAI email client that triages the inbox and drafts replies in your voice, connected to ca…

“OpenAI's models are part of our multi-model architecture. We use different models for different tasks within Slashy: some optimized for speed, others for nuance. OpenAI's API reliability and breadth of capabilities made it a natural part of our stack.”

LLM APIMaker says so +1 · source ↗
BrewDesigns and sends marketing emails and email automations from a plain-English descriptio…

“The most reliable foundation model for fast, high-quality copy generation.”

LLM APIMaker says so +1 · source ↗
OmnifactPrivacy First AI Chat Assistants for Businesses

“Shoutout to OpenAI for kickstarting the generative AI revolution with ChatGPT! Their groundbreaking work has inspired countless innovations. We're excited to build on their achievements and grateful for their, ahem, "privacy concerns" that helped make our product possible. Proud to have supported OpenAI's models from the start. Here's to advancing AI while keeping data safe!”

LLM APIMaker says so +1 · source ↗
Toffu AIMarketing agent that doesn’t circle back tomorrow

“ChatGPT Atlas is a groundbreaking browser that integrates ChatGPT right into your workflow. The seamless sidebar experience enables quick summarization and analysis of content without switching tabs. It truly feels like having a smart assistant on every page, improving productivity and delivering a more intuitive browsing experience.”

LLM APIMaker says so +1 · source ↗
Traycer AIPlan-first AI coding for real codebases

“Provides state-of-the-art LLMs for reasoning and codebase understanding. Powers planning and verification workflows in Traycer.”

LLM APIMaker says so +1 · source ↗
CekuraAutomated QA for Voice AI and Chat AI agents

“We use OpenAI models for parts of automated scenario generation, evaluation and building some of our pre-defined metrics”

LLM APIMaker says so +1 · source ↗
KorlAI agents for customer presentations

“Great array of models for different purposes, and love the playground for quick exploration”

LLM APIMaker says so +1 · source ↗
Glitter AITurn any process into a step-by-step guide ✨

“I mean, come on, literally none of this would have been possible without the amazing work that Sam and his team have been doing for years. At this point "having" AI your product is basically OpenAI :)”

LLM APIMaker says so +1 · source ↗
RunLLMAI that doesn’t just respond—it resolves

“Still the most consistent model for high-stakes support answers. GPT-4-turbo gives us control, reliability, and depth — all critical for enterprise use. Most production-ready reasoning and tool use stability.”

LLM APIMaker says so +1 · source ↗
folkLightweight CRM for managing contacts, pipelines, and outreach, built around a browser e…

“Among the main LLM provider for power our assistants.”

LLM APIMaker says so +1 · source ↗
CortexLet your AI search all your workspace apps, at once

“We use GPT-4 internally for writing copy (like this one!) and in our app to give our users the highest quality of GenAI answers possible”

LLM APIMaker says so +1 · source ↗

Open source: a project that declares OpenAI API as a dependency in its public code — verifiable, but not necessarily a live product.

What makers say

503 makers on why they use OpenAI API, in their own words on Product Hunt.

We chose OpenAI for the combination of engineering depth, integrated tooling, and its investment in defensive security. Stile operates in identity verification, where edge cases and security boundaries matter. Codex’s GitHub code review integration fits directly into our development process. Specialized agents let us tackle implementation, testing, security review, and documentation in parallel, while generous usage limits give us room to iterate. Daybreak’s focus on finding vulnerabilities, validating risks, and developing fixes makes the ecosystem especially compelling for a company building security-sensitive infrastructure. GPT-image-2 has also been a huge help to our marketing team, from creating visuals for the Stile website to developing presentations for client meetings. It helps us turn complex identity-verification concepts into visuals customers can understand. OpenAI stands out because it supports meaningful work across engineering, security, and marketing, all within the same ecosystem.
Stile.iDSep 2026 ↗
Mentions crunches tons of data to give you actionable insights—thanks to GPT-4o. Its advanced NLP understands context, sentiment, and trends way better than older models. Smarter analysis, fewer false positives, and actual useful results. We tested several AI models (including Claude 3 & Gemini) before choosing GPT-4o for Mentions’ analysis—here’s why: Its multimodal chops, speed, and nuanced understanding of context blow older models out of the water. Fewer false positives, sharper sentiment detection, and way better handling of sarcasm (because the internet is wild). For tracking what matters, GPT-4o was the clear winner.
MentionsSep 2026 ↗
GPT-5 is the engine behind every AI feature in Cloud World Model - bottleneck analysis, autoscaling explanations, architecture optimization suggestions, and beginner mode (which rewrites technical output into plain English). The quality of reasoning matters here: users trust these explanations to make real infrastructure decisions. GPT-5 consistently gives specific, actionable answers rather than generic advice, and the structured output reliability made it straightforward to integrate into a simulation pipeline where the AI response has to parse cleanly every time.
Cloud World ModelSep 2026 ↗
GPT-5 is the engine behind every AI feature in Cloud World Model - bottleneck analysis, autoscaling explanations, architecture optimization suggestions, and beginner mode (which rewrites technical output into plain English). The quality of reasoning matters here: users trust these explanations to make real infrastructure decisions. GPT-5 consistently gives specific, actionable answers rather than generic advice, and the structured output reliability made it straightforward to integrate into a simulation pipeline where the AI response has to parse cleanly every time.
Cloud World ModelJun 2026 ↗
OpenAI provided us the API and tooling necessary for us to build out validation, eval harnesses, comparisons, and split out tasks with varying model sizes to ensure we tackle the big problems (document generation) correctly, and smaller problems (organizing, in-line analysis, etc.) with smaller models. The flexibility and breadth of their AI offerings was a natural fit with Moxie Docs. GPT 5.6 Sol and their latest models alongside Codex greatly enhances our delivery timeline, ability to audit and improve code performance and refactoring, and our long term success.
Moxie DocsSep 2026 ↗

Loved and watch-outs

Themes that recur in makers' words and Hacker News comments, each linked to what it summarises, with how Product Hunt tags its reviews.

Most loved
  • Its models are strong at code generation, reasoning and creative tasks, often chosen after testing alternatives. PHPH 2PH 3PH 4
  • The API is reliable and well-priced as the foundation for production features. PHPH 2PH 3HN
  • Good docs and a smooth developer experience make integration straightforward. PHPH 2PH 3PH 4
  • Whisper gives accurate speech-to-text across many languages. PHPH 2PH 3
Watch-outs
  • It cut usage on the $200 Pro plan and changed limits, frustrating paying subscribers. HNHN 2HN 3HN 4
  • Model quality shifts between releases, including a quickly replaced GPT-6 and quietly tweaked reasoning levels. HNHN 2HN 3HN 4
  • Models flag or stop midway on legitimate security work. HNHN 2
On Product Hunt 5.0★ · 860 reviews
AI API 52AI productivity boost 34fast performance 34AI innovation 33AI integration ease 33AI model variety 25AI natural language processing 21AI creativity enhancement 19AI accuracy issues 13AI pricing 7AI ethical concerns 4AI bias 2
Read the reviews on Product Hunt ↗

Reliability and open issues

Incidents on its status page25+ in the last 90 days, 4 major · 25+ in the last year
  • major Issues with login, signup, and ads Oct 2026
  • minor Elevated latency for some API requests Sep 2026
  • minor Elevated error rates for ChatGPT Pro and Plus users Sep 2026
From its own status page, 2026-10-02. Vendors decide what they post; one page can cover several products.

Who switches

Public pull requests on GitHub since Oct 2024 whose title says "X to Y" — real code changes moving a project from one tool to another, by developers in general. Open a row to see the pull requests.

Gemini API → OpenAI API90+ PRs
Claude → OpenAI API89 PRs
Groq → OpenAI API25 PRs
DeepSeek → OpenAI API16 PRs
Mistral AI → OpenAI API4 PRs
OpenAI API → Gemini API179+ PRs
OpenAI API → Claude127 PRs
OpenAI API → Groq50 PRs
OpenAI API → DeepSeek23 PRs
OpenAI API → Mistral AI9 PRs

Alternatives to OpenAI API

All alternatives by situation →

On Product Hunt, people weigh it against: Mistral AI, Claude, MiniMax, Grok API, Gemini API, Eden AI.

Questions makers ask about OpenAI API

Does OpenAI train its models on what I send through the API?

No, not by default. Data sent to the API has not been used for training since March 1, 2023, unless you explicitly opt in to share it. source ↗

How long does OpenAI keep my prompts and outputs?

By default, abuse-monitoring logs that can include prompts and responses are kept for up to 30 days, and the Responses API stores response objects for at least 30 days unless you set store to false. Zero Data Retention and Modified Abuse Monitoring exist, but they require OpenAI's prior approval. source ↗

Can I keep my data in the EU or another region?

Yes, if you are eligible, which is decided through sales. Data residency is set per project, stores customer content at rest in the chosen region, and in some regions also runs inference there. Non-US regions also require approval for abuse-monitoring controls. source ↗

Can I use it for health data under HIPAA?

Only after signing OpenAI's Business Associate and Healthcare Addendum and having your organization provisioned for it. PHI can then go only through BAA-eligible endpoints; web search with live internet access, for example, isn't covered. source ↗

How do rate limits work for a new account?

Limits apply per organization and per project, not per user, and are measured in requests and tokens per minute and per day. As your total paid spend grows, OpenAI moves you up usage tiers automatically, which raises your limits and your monthly usage cap. source ↗

Is there a cheaper way to run large offline jobs?

Yes. The Batch API takes a .jsonl file of requests, finishes within 24 hours, and costs half as much as the same calls made synchronously. source ↗

Which languages have an official SDK?

JavaScript/TypeScript (Node.js, Deno, Bun), Python, .NET, Java, Go and Ruby. Java and Go are labeled beta, and there are official Agents SDKs for TypeScript and Python. source ↗

Should I build on Chat Completions or the Responses API?

OpenAI recommends Responses for all new projects. It adds built-in tools and optional server-side conversation state, while Chat Completions remains supported. source ↗

Is OpenAI API free?

No permanent free tier; paid use starts at Pay per token. source ↗

Is OpenAI API open source or self-hostable?

Not open source, and hosted only.

Can AI coding agents work with OpenAI API?

It serves an llms.txt docs index; Lovable, Replit set it up natively.

Who uses OpenAI API?

734 makers' products we track, each with a source, and 481 open-source projects declare it in their code. source ↗