AI APIs expose large language models, image generators, speech-to-text, and embedding models over HTTP. Pricing is typically per-token or per-request, with free tiers that are enough for prototyping. Check rate limits and latency carefully — these are the two signals that determine whether an AI API works in production. CORS support varies: some providers allow browser calls, others require a backend proxy.
| API | Pricing | Auth | CORS | Health | |
|---|---|---|---|---|---|
| Google Vertex AI API Google Cloud API for enterprise AI model serving, Gemini on Vertex AI, datasets, tuning, agents, and ML operations. | Paid | Unknown | No | Profile | |
| Groq API Groq API: ultra-fast LLM inference with dedicated hardware for real-time AI applications. | Freemium | API Key | No | Profile | |
| GroqCloud API Run open AI models with low-latency inference through OpenAI-compatible chat, responses, audio, batch, and fine-tuning APIs. | Freemium | API Key | No | Profile | |
| HeyGen API AI avatar and talking-head video generation at scale. | Unknown | Unknown | Yes | Profile | |
| Hugging Face API Hugging Face API: access 300K+ open-source ML models, datasets, and Spaces for inference and fine-tuning. | Freemium | API Key | No | Profile | |
| Hugging Face Hub API Hub API for models, datasets, Spaces, repositories, files, and metadata. | Freemium | API Key | Yes | Profile | |
| Hugging Face Inference API Serverless inference for 100k+ open models: text, image, audio and embeddings. | Unknown | Unknown | Yes | Profile | |
| Hugging Face Inference Providers Access open models across multiple inference providers through one token and OpenAI-compatible API. | Freemium | API Key | No | Profile | |
| Humanloop API LLM prompt, evaluation, dataset, and observability API for managing AI product development workflows. | Paid | API Key | No | Profile | |
| Hume AI API Empathic voice and expression measurement APIs for multimodal AI products. | Freemium | API Key | Yes | Profile | |
| Hyperbolic API Hyperbolic GPU cloud and inference API for open models with serverless endpoints, dedicated deployments, and competitive per-token pricing. | Freemium | API Key | No | Profile | |
| IBM Text to Speech Convert text to speech | Freemium | API Key | Yes | Profile | |
| Ideogram API Ideogram API for state-of-the-art text rendering inside generated images, with style presets, remixing, and upscaling. | Freemium | API Key | No | Profile | |
| Jina AI API Jina AI APIs for embeddings, reranking, reader (URL-to-markdown), web search grounding, and image captioning for LLM pipelines. | Freemium | API Key | Yes | Profile | |
| Jina Reader API URL-to-clean-markdown reader API for retrieval, RAG, and agent browsing. | Freemium | API Key | Yes | Profile | |
| Jina Reranker API Reranking API for improving retrieval and RAG result ordering. | Freemium | API Key | Yes | Profile | |
| Lambda Inference API Lambda Inference API for serving open-source LLMs on Lambda GPU infrastructure with an OpenAI-compatible chat completions endpoint. | Freemium | API Key | No | Profile | |
| LangSmith API LangSmith API for LLM observability: trace capture, dataset management, evaluation runs, and prompt hub operations from the LangChain team. | Freemium | API Key | No | Profile | |
| Langfuse API Langfuse open-source LLM engineering platform API for traces, evaluations, prompt management, and cost analytics. Self-host or use cloud. | Freemium | API Key | No | Profile | |
| Leonardo AI API Leonardo AI image-generation API with fine-tuned models, canvas editing, motion, and real-time generation for game art and creative production. | Freemium | API Key | No | Profile | |
| Luma Dream Machine API Luma Dream Machine API for high-quality text-to-video and image-to-video generation, including keyframe interpolation via Ray2 models. | Paid | API Key | No | Profile | |
| Manga Translator API AI manga-image translation API with asynchronous batch workflows and multilingual output. | Freemium | API Key | Unknown | Profile | |
| Meta Llama API Hosted Llama models via Meta's official Llama API. | Unknown | Unknown | Yes | Profile | |
| MiniMax API MiniMax video, music and chat models for developers. | Unknown | Unknown | Yes | Profile | |
| Mistral AI API Run Mistral models for chat, reasoning, embeddings, OCR, audio, agents, moderation, and batch inference. | Freemium | API Key | No | Profile | |
| Modal API Serverless compute and ML app deployment API for Python workloads. | Freemium | API Key | Yes | Profile | |
| Moonshot Kimi API Kimi long-context chat models via an OpenAI-compatible API. | Unknown | Unknown | Yes | Profile | |
| NVIDIA NIM API Run optimized NVIDIA NIM microservices for language, retrieval, vision, multimodal, healthcare, and simulation models. | Freemium | API Key | No | Profile | |
| Nebius AI Studio API Nebius AI Studio hosted inference for Llama, DeepSeek, Qwen, and embedding models with OpenAI-compatible endpoints on NVIDIA infrastructure in Europe. | Freemium | API Key | No | Profile | |
| Nomic AI API Nomic Atlas and embed APIs for multimodal embeddings, dataset curation, and interactive exploration of unstructured data at scale. | Freemium | API Key | No | Profile | |
| Novita AI API Novita AI API for LLM inference plus image, video, and audio generation model library with pay-as-you-go serverless GPU hosting. | Freemium | API Key | No | Profile | |
| Open AI Klarna product Api Open AI Klarna product Api public API. | Paid | Unknown | Yes | Profile | |
| OpenAI Build AI-powered applications with OpenAI's REST, streaming, and realtime APIs. Access GPT, DALL-E, Whisper, and more. | Paid | API Key | No | Profile | |
| OpenIndex Retrieval Plugin API A retrieval API for querying and filtering documents based on natural language queries and metadata | Free | API Key | Yes | Profile | |
| OpenPipe API LLM logging, dataset, fine-tuning, and model evaluation API for reducing AI cost and latency. | Freemium | API Key | No | Profile | |
| Originality.ai API Originality.ai API for AI detection, plagiarism checking, readability scoring, and fact-checking assistance built for content publishers. | Paid | API Key | No | Profile | |
| Pandorabots AIaaS API AIaaS provides API access to our bot hosting platform and SDKs, allowing developers to easily integrate conversational interfaces into applications. | Unknown | Unknown | Yes | Profile | |
| Perplexity AI API Perplexity AI API: real-time web-grounded LLM with citations for research, search, and conversational AI. | Freemium | API Key | No | Profile | |
| Perplexity API Build grounded search and research applications with web citations, structured output, and reasoning models. | Paid | API Key | No | Profile | |
| Perplexity Sonar API Grounded, citation-ready answers from the web via Perplexity's Sonar search models. | Unknown | Unknown | Yes | Profile | |
| Photoroom API Photoroom API for AI product photography: background removal, shadows, resizing, and instant backgrounds optimized for e-commerce catalogs. | Freemium | API Key | No | Profile | |
| PlayHT API PlayHT voice-generation API for ultra-realistic text-to-speech, voice cloning, and speech-to-speech conversion with streaming output. | Freemium | API Key | No | Profile | |
| PromptLayer API Prompt management, evaluation, tracing, and release workflow API for production LLM applications. | Freemium | API Key | No | Profile | |
| Proxed AI Secure AI API proxy for iOS apps. Route AI requests through Proxed without SDK integration - just swap the API URL. | Freemium | API Key | Yes | Profile | |
| Recraft API Recraft API for generative design: raster and vector (SVG) image generation with brand-style control, background removal, and upscaling. | Freemium | API Key | No | Profile | |
| Replicate API Run, fine-tune, deploy, and manage public or custom machine-learning models through a unified API. | Paid | API Key | No | Profile | |
| Rev AI API Rev AI speech-to-text API delivering asynchronous and streaming transcription with high accuracy on challenging audio. Pay-as-you-go and subscription options. | Paid | API Key | No | Profile | |
| Runway API Runway REST API for Gen-3 Alpha and Gen-4 video generation: text-to-video, image-to-video, and video-to-video with programmatic job management. | Paid | API Key | No | Profile | |
| SambaNova Cloud API SambaNova Cloud API for fast inference on open-source LLMs including Llama and DeepSeek families with enterprise-grade security. | Freemium | API Key | No | Profile | |
| Seldon External API Seldon External API public API. | Unknown | API Key | Yes | Profile | |
| SiliconFlow API Fast low-cost inference for open chat, image and embedding models. | Unknown | Unknown | Yes | Profile | |
| Slack AI Plugin API A plugin that allows users to interact with Slack using ChatGPT | Paid | Unknown | Yes | Profile | |
| Speechmatics API Speechmatics speech-to-text API with high accuracy across 50+ languages, real-time and batch modes, and custom dictionary support. | Freemium | API Key | No | Profile | |
| Stability AI API Generate and edit images, upscale assets, and create 3D or audio content with Stability AI models. | Paid | API Key | No | Profile | |
| Synthesia API Create studio-quality avatar videos programmatically. | Unknown | Unknown | Yes | Profile | |
| Tencent Hunyuan API Hunyuan multimodal LLMs on Tencent Cloud. | Unknown | Unknown | Yes | Profile | |
| Together AI API Run and fine-tune open models for chat, embeddings, images, video, audio, and dedicated inference. | Paid | API Key | No | Profile | |
| Upstage Solar API Upstage Solar LLM API from Korea with strong Korean-language performance, plus document OCR (Document Parse) and layout analysis endpoints. | Freemium | API Key | No | Profile | |
| Vectara REST API Vectara is a neural search platform, built for developers to get the most out of their data. You can sign up for an account at [https://vectara.com](https://vectara.com). | Unknown | Unknown | Yes | Profile | |
| Voyage AI API Voyage AI embedding and reranking models purpose-built for retrieval-augmented generation, code search, and multimodal search pipelines. | Freemium | API Key | No | Profile | |
| Wellknown API A registry of AI Plugins. | Free | Unknown | Yes | Profile | |
| Winston AI API Winston AI API for AI-image and AI-text detection with high claimed accuracy, used by publishers and educators. | Paid | API Key | No | Profile | |
| Wolframalpha Wolfram API Wolframalpha Wolfram API public API. | Paid | Unknown | Yes | Profile | |
| Writer API Writer platform API exposing Palmyra LLMs for no-hallucination enterprise generation, plus knowledge graphs, agents, and guardrails. | Paid | API Key | No | Profile | |
| Zhipu BigModel API GLM frontier models and embeddings from Zhipu AI. | Unknown | Unknown | Yes | Profile | |
| api.datumbox.com API Datumbox offers a Machine Learning platform composed of 14 classifiers and Natural Language processing functions. Functions include sentiment analysis, topic classification, readability assessment, language detection, an | Paid | API Key | Yes | Profile | |
| fal Model APIs Access 1,000+ production-ready image, video, audio, and multimodal generation models. | Paid | API Key | No | Profile | |
| iLook Face Analysis API Analyzes visible facial features in submitted images and returns structured, non-medical appearance reports, with privacy-first handling and transient image processing. | Free | API Key | No | Profile | |
| xAI API Build with Grok models across text, code, voice, image, video, tools, and realtime experiences. | Paid | API Key | No | Profile |
For AI APIs, prioritize latency and rate limits over raw model quality — a slightly weaker model with 10x the throughput often ships better products. Check whether the provider supports streaming, function calling, and your required context window before prototyping.