Free Developer Tool
API Payload Generator
Generate ready-to-use JSON payloads, cURL commands, and SDK code for OpenAI, Anthropic, Google Gemini, Mistral, and AWS Bedrock APIs in seconds. 100% Browser-Based
stream: true) How to Use This Tool
1. Select a Provider
Choose your LLM provider — OpenAI, Anthropic, Google Gemini, Mistral, or AWS Bedrock. The model list and payload format update automatically.
2. Configure Parameters
Enter your system prompt and user message. Adjust temperature, max tokens, top-p, and toggle streaming. All outputs update in real time.
3. Copy Your Code
Switch between JSON, cURL, Python, and Node.js tabs. Copy the generated code directly into your project — no manual formatting needed.
LLM API Essentials
Provider Differences
Each provider has its own payload structure. OpenAI and Mistral use the same
/chat/completions format.
Anthropic places the system prompt at the top level. Google Gemini uses
contents with parts.
Bedrock uses the Converse API.
Temperature vs Top-P
Temperature controls randomness: 0 = deterministic, 1 = balanced, 2 = very creative. Top-P (nucleus sampling) restricts the token pool: 1 = all tokens, 0.1 = only the top 10% most likely tokens. Most guides recommend adjusting one or the other, not both.
Streaming Responses
With stream: true,
the API sends tokens as they are generated via Server-Sent Events (SSE). This dramatically
improves perceived latency for long responses. Handle streaming with
for await...of
in the official SDKs.
100% Client-Side
All payload generation runs entirely in your browser. Your prompts, API keys, and configuration are never sent to any server. Works offline after the initial page load.
Provider API Quick Reference
| Provider | Base URL | Auth Header | Format |
|---|---|---|---|
| OpenAI | api.openai.com/v1 | Authorization: Bearer | Chat Completions |
| Anthropic | api.anthropic.com/v1 | x-api-key | Messages API |
| Google Gemini | generativelanguage.googleapis.com | ?key= param | generateContent |
| Mistral | api.mistral.ai/v1 | Authorization: Bearer | Chat Completions |
| AWS Bedrock | bedrock-runtime.*.amazonaws.com | AWS Sig v4 | Converse API |
Common Use Cases
API Prototyping
Quickly build and test payloads before writing integration code. Use the cURL output to validate your prompts directly from the terminal.
Provider Migration
Switch between providers instantly to compare payloads and identify differences. Simplifies migrating applications from one LLM vendor to another.
Documentation & Onboarding
Generate accurate, working code examples for internal docs, tutorials, and developer onboarding materials across multiple providers.
Build LLM-Powered Applications
From API integration to production AI pipelines — we design and deploy LLM integrations, RAG systems, and intelligent agents that are reliable, cost-effective, and production-ready.
Talk to Our AI Team