PromptThin

Reduce LLM API costs through caching, compression, and smart routing. Zero code changes.

PromptThin is a transparent proxy that sits between your AI agents and LLM providers. Two environment variables and you're done — every API call gets four compounding savings routes applied automatically.

Your app ──→ PromptThin ──→ OpenAI / Anthropic / Gemini / Groq

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Four savings routes

Route	What it does	Saving
Semantic Cache	Returns cached answers for similar questions — even if worded differently	Up to 100% on repeated queries
Prompt Compression	Compresses verbose prompts with LLMLingua 2 before sending	Up to 50% on input tokens
Model Router	Automatically routes simple tasks to cheaper models in <1ms	Up to 90% per request
Context Pruning	Summarises long conversation history when it exceeds 8K tokens	Up to 60% on long threads

All four routes run on every request. You control which to skip per-request via headers.

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Get started in 2 minutes

Step 1 — Create an account

Sign up at promptthin.tech — verify your email, then start your 7-day free trial (no charge for 7 days).

Or via API:

curl -X POST https://promptthin.tech/auth/register
-H "Content-Type: application/json"
-d '{"email": "[email protected]", "password": "yourpassword"}'

Password requirements: 8+ characters, uppercase, lowercase, number, special character. Check your inbox for a verification email before making API calls.

Step 2 — Register your LLM provider key

OpenAI

curl -X POST https://promptthin.tech/keys/openai
-H "X-API-Key: ts_your_key"
-H "Content-Type: application/json"
-d '{"key": "sk-your-openai-key"}'

Anthropic

curl -X POST https://promptthin.tech/keys/anthropic
-H "X-API-Key: ts_your_key"
-H "Content-Type: application/json"
-d '{"key": "sk-ant-your-anthropic-key"}'

Gemini

curl -X POST https://promptthin.tech/keys/gemini
-H "X-API-Key: ts_your_key"
-H "Content-Type: application/json"
-d '{"key": "AIza-your-gemini-key"}'

Groq

curl -X POST https://promptthin.tech/keys/groq
-H "X-API-Key: ts_your_key"
-H "Content-Type: application/json"
-d '{"key": "gsk_your-groq-key"}'

Your provider keys are encrypted with AES-256 and never appear in logs or responses.

Step 3 — Point your app at PromptThin

.env — two lines, no other changes needed

OPENAI_BASE_URL=https://promptthin.tech/v1 OPENAI_API_KEY=ts_your_key

Done. Every LLM call now routes through PromptThin and savings start immediately.

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Integration examples

OpenAI SDK — Python

from openai import OpenAI

client = OpenAI( base_url="https://promptthin.tech/v1", api_key="ts_your_key", )

response = client.chat.completions.create( model="gpt-4o", messages=[{"role": "user", "content": "Hello!"}] )

OpenAI SDK — JavaScript / TypeScript

import OpenAI from "openai";

const client = new OpenAI({ baseURL: "https://promptthin.tech/v1", apiKey: "ts_your_key", });

Anthropic SDK — Python

import anthropic

client = anthropic.Anthropic( base_url="https://promptthin.tech", api_key="ts_your_key", )

Anthropic SDK — JavaScript

import Anthropic from "@anthropic-ai/sdk";

const client = new Anthropic({ baseURL: "https://promptthin.tech", apiKey: "ts_your_key", });

LangChain

from langchain_openai import ChatOpenAI

llm = ChatOpenAI( base_url="https://promptthin.tech/v1", api_key="ts_your_key", model="gpt-4o", )

AutoGen

config_list = [{ "model": "gpt-4o", "base_url": "https://promptthin.tech/v1", "api_key": "ts_your_key", }]

CrewAI / any OpenAI-compatible framework

OPENAI_BASE_URL=https://promptthin.tech/v1 OPENAI_API_KEY=ts_your_key

Vercel AI SDK

import { createOpenAI } from "@ai-sdk/openai";

const openai = createOpenAI({ baseURL: "https://promptthin.tech/v1", apiKey: "ts_your_key", });

LiteLLM

import litellm

litellm.api_base = "https://promptthin.tech/v1" litellm.api_key = "ts_your_key"

Cursor / Continue.dev / Open WebUI

In settings, set:

• OpenAI API Base URL: https://promptthin.tech/v1
• API Key: ts_your_key

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Supported models

PromptThin infers the provider from the model name automatically:

Model prefix	Routes to
gpt-*, o1-*, o3-*	OpenAI
claude-*	Anthropic
gemini-*	Google Gemini
llama-*, mixtral-*, gemma-*	Groq

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Preview savings before committing

Use the POST /predict-savings endpoint to get a cost estimate before making a real LLM call — no tokens billed, no LLM call made:

curl -X POST https://promptthin.tech/predict-savings
-H "X-API-Key: ts_your_key"
-H "Content-Type: application/json"
-d '{ "model": "gpt-4o", "provider": "openai", "messages": [ {"role": "user", "content": "your long prompt here..."} ] }'

Response:

{ "original_tokens": 4200, "estimated_tokens_after_savings": 2100, "estimated_cost_original": 0.0105, "estimated_cost_after_savings": 0.0013, "estimated_saving": 0.0092, "saving_percent": 87.5, "recommendation": "proceed" }

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MCP server

Add to claude_desktop_config.json:

{ "mcpServers": { "promptthin": { "url": "https://promptthin.tech/mcp", "headers": { "X-API-Key": "ts_your_key" } } } }

Available tools: get_usage_summary, get_billing_status, flush_cache, get_recent_requests.

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Per-request controls

Header	Value	Effect
X-Cache-Control	no-cache	Skip cache lookup and storage
X-Prune-Control	no-prune	Skip context pruning
X-Compress-Control	no-compress	Skip prompt compression
X-Router-Control	no-route	Skip model routing

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Pricing

Plan	Price	Requests
No card	Free	20 requests to explore
Pro	7-day free trial · then $4.99 first month · then $11.99/mo	Unlimited
Enterprise	Custom	Unlimited + SLA + dedicated support

Start free trial →

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Security

• Provider keys encrypted with AES-256 — never in logs or responses
• Email verification required before making API calls
• Strong passwords enforced (8+ chars, upper, lower, number, special character)
• All traffic HTTPS only
• Keys stored in GCP Secret Manager

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FAQ

**Do I need to change my code?**No. Set two environment variables.

**Does PromptThin slow down my requests?**Cache hits completely skip the LLM call — dramatically lower latency. Cache misses add <2ms overhead.

What if I want to pass my provider key directly?

client = OpenAI( base_url="https://promptthin.tech/v1", api_key="ts_your_key", default_headers={"Authorization": "Bearer sk-your-openai-key"}, )

PromptThin detects the key prefix and uses it directly.

**Can I use multiple providers?**Yes. Register keys for each provider. PromptThin routes to the right one based on the model name.

**What happens after the 7-day trial?**Your card is charged $4.99 for the first month, then $11.99/month. Cancel anytime from the dashboard — no charge if cancelled within 7 days.

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Contact

• Website: promptthin.tech
• Enterprise: [email protected]
• Issues: Open an issue on this repository