Using the Sealos AI Proxy to Manage and Cache LLM API Calls

Large Language Models (LLMs) are unbelievably powerful—but they can also be slow, expensive, and operationally tricky. If you’ve ever hit provider rate limits, paid more than expected for a spike in traffic, or wrestled with SDK differences across models, you know the pain. That’s where an AI proxy comes in.

The Sealos AI Proxy gives you a single, OpenAI-compatible endpoint you can point your apps to, while it handles provider routing, key management, caching, rate limiting, and observability behind the scenes. Whether you’re shipping a high-QPS chatbot or a cost-sensitive batch pipeline, a smart proxy can dramatically simplify your stack and stabilize performance.

In this guide, you’ll learn what the Sealos AI Proxy is, why it’s important, how it works, and how to use it in real projects. We’ll walk through best practices for caching prompts, controlling costs, and keeping your applications fast and reliable. If you’re already deploying apps on Sealos—an open-source, Kubernetes-native cloud operating system—you’ll find the proxy integrates naturally with the Sealos platform and ecosystem (see sealos.io).

What you’ll learn

• What the Sealos AI Proxy is and when to use it
• The challenges it solves: performance, cost, portability, and governance
• How the proxy’s caching and routing work in practice
• How to integrate it using OpenAI-compatible clients
• Real-world patterns for chatbots, RAG, batch jobs, and more
• Best practices for performance, correctness, and security

What Is the Sealos AI Proxy?

The Sealos AI Proxy is a centralized gateway that sits between your applications and LLM providers (e.g., OpenAI-compatible services, other model vendors, or your own self-hosted models). Instead of embedding provider-specific SDKs and keys in each service, you point your code at the proxy. The proxy then:

• Normalizes requests via an OpenAI-compatible API
• Manages multiple upstream providers and models
• Adds caching layers to reduce latency and cost
• Enforces rate limits, quotas, and timeouts
• Collects metrics and logs for observability
• Simplifies key management and access control

Because it’s OpenAI-compatible, you can often switch your code to use the proxy by changing the base URL and the API key—without rewriting business logic.

If you deploy on Sealos, you can run the AI Proxy alongside your apps, databases, and RAG pipelines on a Kubernetes-native platform that emphasizes simplicity, isolation, and scalability. Learn more about Sealos at https://sealos.io.

Why Managing and Caching LLM Calls Matters

The real-world problems the proxy addresses

• Cost spikes: LLM calls can get expensive quickly, especially for high-traffic endpoints or long prompts. Caching reduces redundant calls and controls spend.
• Latency and tail behavior: Users notice slow, spiky responses. Caching cuts p95/p99 latency for common requests, and routing lets you choose faster or nearer providers.
• Provider fragmentation: Each provider has its own SDKs, headers, and limits. A proxy creates a unified interface and model aliases.
• Key sprawl and security: Storing raw provider keys across many services is risky. Centralized key management reduces exposure and simplifies rotation.
• Rate limits and reliability: Hit a threshold? A proxy can queue, throttle, retry, or fail over to backups rather than letting requests crash your app.
• Observability: A single control point gives you metrics across providers—token usage, costs, latency, error rates, cache hit ratios—so you can optimize effectively.

When to use an AI proxy

• You depend on multiple LLM providers or plan to switch providers over time
• You have repeated prompts or content where caching makes sense
• You need centralized limits, governance, and auditing for AI usage
• You want to improve performance without rewriting application code
• You’re building on Sealos and want a unified, open-source friendly stack

How the Sealos AI Proxy Works

At a high level, the proxy accepts OpenAI-compatible requests (e.g., /v1/chat/completions), normalizes them, and routes them to the appropriate upstream resource based on your policy. It can apply caching, rate limiting, and retries before/after the upstream call, and it records metrics and logs for analysis.

Key components typically include:

• API Gateway: An OpenAI-compatible surface for chat/completion/embedding endpoints
• Provider Connectors: Configured connections to upstream vendors or self-hosted models
• Router/Policy Engine: Rules to select a provider/model based on cost, latency, region, or A/B tests
• Cache: Response cache for deterministic prompts, plus optional semantic caches where appropriate
• Rate Limiter: Token-based or request-based throttling and quotas
• Retry and Circuit Breakers: Resilience to transient failures and timeouts
• Observability: Logs, traces, and metrics for usage, cost, errors, and cache hit rate
• Access Control: Project-level keys, RBAC, and audit trails

Because the proxy is OpenAI-compatible, the request/response schema stays familiar. Your application continues to send messages, temperatures, and model names; the proxy handles the rest.

Getting Started: Integrating the AI Proxy

You can often integrate the Sealos AI Proxy by changing only two things in your code:

• Set the base URL to the proxy endpoint
• Use the proxy-issued API key instead of a provider key

Below are example snippets. Replace <YOUR_AI_PROXY_BASE_URL> and <YOUR_PROXY_API_KEY> with values from your Sealos AI Proxy configuration.

cURL example

curl https://<YOUR_AI_PROXY_BASE_URL>/v1/chat/completions \
  -H "Authorization: Bearer <YOUR_PROXY_API_KEY>" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-4o",
    "messages": [
      {"role":"system","content":"You are a concise assistant."},
      {"role":"user","content":"Explain Sealos in one sentence."}
    ],
    "temperature": 0
  }'

JavaScript (Node) with OpenAI SDK

import OpenAI from "openai";
 
const client = new OpenAI({
  apiKey: process.env.PROXY_API_KEY,
  baseURL: "https://<YOUR_AI_PROXY_BASE_URL>/v1",
});
 
const completion = await client.chat.completions.create({
  model: "gpt-4o",
  messages: [
    { role: "system", content: "You are a concise assistant." },
    { role: "user", content: "Explain Sealos in one sentence." },
  ],
  temperature: 0,
});
 
console.log(completion.choices[0].message);

Python with openai

from openai import OpenAI
import os
 
client = OpenAI(
    api_key=os.environ["PROXY_API_KEY"],
    base_url="https://<YOUR_AI_PROXY_BASE_URL>/v1"
)
 
resp = client.chat.completions.create(
    model="gpt-4o",
    messages=[
        {"role": "system", "content": "You are a concise assistant."},
        {"role": "user", "content": "Explain Sealos in one sentence."}
    ],
    temperature=0
)
print(resp.choices[0].message)

Notes:

• The model name can be an alias managed by the proxy. Aliases let you switch underlying providers without code changes.
• For streaming responses, use the SDK’s streaming features. The proxy preserves server-sent events (SSE) semantics where supported.

Caching LLM Responses: What, Why, and How

Caching is the single biggest lever to improve performance and reduce cost for many LLM workloads. The Sealos AI Proxy adds a cache between your app and upstream providers, which can turn repeated prompts into instant, no-cost hits.

What to cache (and what not to)

Below is a simple guide for deciding when to cache:

Deterministic caching

For exact-match caching to be effective:

• Set temperature=0 (or a low, consistent value)
• Keep other sampling parameters stable (top_p, presence_penalty, frequency_penalty)
• Normalize requests (e.g., consistent whitespace, ordering of message fields)
• Cache key includes the model alias, full message content, and all sampling params

When your app ensures deterministic inputs, the proxy can reliably serve the identical output from cache.

Semantic caching

Some workloads benefit from semantic caches that treat “similar” prompts as equivalent. This is more advanced and may require embedding-based similarity checks. Consider semantic caching only when:

• Your domain tolerates near-duplicate answers
• You have a clear threshold for similarity
• You accept occasional minor variations in response quality

If you use semantic caching, constrain it to non-critical paths or provide fallbacks.

TTLs and invalidation

• Choose TTLs based on content volatility. For static FAQs, TTLs of hours/days are fine. For news or inventory, stick to minutes or shorter.
• Invalidate on content updates. For RAG, invalidate or version cache keys when underlying documents change.
• Build a version bit into cache keys. E.g., include “prompt_schema_version=2” so you can invalidate caches during prompt upgrades.

Streaming vs. non-streaming

• Non-streaming responses are straightforward to cache.
• For streaming (SSE), you can cache the final transcript or chunks. Make sure your proxy preserves stream semantics. Some teams cache the final assembled text only to simplify downstream handling.

Privacy and correctness

• Avoid caching PII or sensitive prompts unless you have a clear policy, encryption at rest, and strict access controls.
• Consider segregating caches per tenant or per project.
• Always include all generation parameters in the cache key to prevent serving mismatched outputs.

Provider Routing and Resilience

Beyond caching, the Sealos AI Proxy can route requests intelligently:

• Model aliases: “general-purpose” or “vision-chat” can map to different underlying models as you optimize for speed or cost.
• Failover: If the primary provider returns 5xx/429 responses, automatically retry another provider or a smaller backup model.
• Cost-aware routing: Send low-priority traffic to lower-cost models; reserve premium models for VIP endpoints.
• Regional/latency routing: Choose providers and regions closer to your users.

Resilience features to look for or configure:

• Idempotency keys to avoid double charges on retries
• Exponential backoff and jitter for transient failures
• Timeouts set per request (client) and per upstream (proxy)
• Circuit breakers to protect upstreams and stabilize p95 latency

Observability and Governance

Centralizing LLM traffic through the proxy unlocks comprehensive visibility:

• Metrics: request counts, token usage, cost per request, cache hit rate, p50/p95/p99 latency, error rates
• Logs: request metadata, model/alias used, route decisions, errors
• Traces: spans for cache check, upstream call, streaming duration
• Budgets and quotas: per team, project, or environment
• Audit trails: who used which key, when, and for what

Observability helps answer practical questions:

• Which prompts are the most expensive?
• Where do we need caching or prompt compression?
• Which models deliver the best latency for our traffic mix?
• Did our prompt change increase or reduce cost?

If you’re running on Sealos, you can pair the proxy with your preferred observability stack and other Sealos apps to build a cohesive platform.

Security, Keys, and Access Control

A proxy lets you standardize security controls:

• Key management: Store provider keys centrally; rotate without touching application code.
• Project keys: Issue short-lived or scoped keys to services and teams; revoke as needed.
• RBAC: Limit which models or providers an app can call.
• Data controls: Redact logs, limit prompt retention, and choose where caching is enabled.
• Network policies: Run the proxy inside your cluster or VPC; control egress to external providers.

Follow best practices:

• Keep proxy-issued keys in your app’s secret store or environment variables.
• Do not embed raw provider keys in client-side code.
• Configure least-privilege access per environment (dev, staging, prod).

Practical Applications and Patterns

1) High-QPS chatbots and assistants

• Cache answers for common questions, especially with temperature=0.
• Use a short TTL (e.g., a few minutes) for semi-dynamic FAQs to balance freshness and performance.
• Add a cost-saving tier: route anonymous/free traffic to smaller models; upgrade for authenticated users.

2) RAG (Retrieval-Augmented Generation)

• Cache embeddings for documents by content hash to avoid re-embedding unchanged text.
• Cache final answers that combine a stable prompt and stable top-k chunks.
• Version your RAG prompt template to invalidate caches when you tweak instructions.

3) Batch summarization and classification

• Run large jobs overnight via the proxy; set conservative rate limits to avoid provider throttling.
• Cache identical or near-identical inputs across batches.
• Track cost per batch via proxy metrics.

4) Pre-generation and edge caching

• Pre-generate outputs (e.g., product descriptions or metadata) during off-peak hours; serve from cache to front-end users.
• Push cached results to edge/CDN where feasible for ultimate latency.

5) Multi-provider redundancy

• Configure a primary provider and a cheaper or more available backup.
• Keep the same model alias in your app; let the proxy flip providers as needed.
• Monitor correctness differences across providers and adjust prompts to stabilize output.

Best Practices for Using the Sealos AI Proxy

• Make prompts cache-friendly:

  • Use temperature=0 for deterministic responses you plan to cache.
  • Canonicalize input (strip irrelevant whitespace, normalize field order).
  • Include a schema version in your prompts or metadata.

• Be explicit about freshness:

  • Choose TTLs based on business needs; err on shorter TTLs for dynamic data.
  • Invalidate caches on content changes or prompt template updates.

• Observe and optimize:

  • Monitor cache hit rate; if low, revisit which endpoints are cache-eligible.
  • Track p95 latency; caching is most valuable when tail latency is high.
  • Watch cost per request; test smaller models where acceptable.

• Manage limits and retries:

  • Configure sensible rate limits per project.
  • Use idempotency keys in your app for retryable operations.
  • Set timeouts both client-side and proxy-side.

• Secure by default:

  • Use Sealos or your secret manager to store proxy keys.
  • Scope access by environment and team.
  • Avoid caching sensitive content unless encrypted and segregated.

Example: Migrating an Existing App to the Proxy

Suppose you have a Node.js app using the OpenAI SDK directly. Here’s a simple migration path:

1. Provision the Sealos AI Proxy

• Deploy the proxy on Sealos or access a managed endpoint.
• Configure provider connections (e.g., OpenAI, others) and create model aliases.
• Generate a project-scoped API key.

2. Update your application config

• Replace the SDK’s base URL with the proxy endpoint.
• Update the API key to the proxy-issued key.
• Optionally set temperature=0 on routes you want to cache.

3. Verify behavior

• Run integration tests for chat/completions and streaming.
• Check proxy metrics for traffic, latency, and hit rate.
• Adjust TTLs and cache scope based on observed patterns.

Minimal code change example:

// before
import OpenAI from "openai";
const openai = new OpenAI({ apiKey: process.env.OPENAI_API_KEY });
 
// after
import OpenAI from "openai";
const openai = new OpenAI({
  apiKey: process.env.PROXY_API_KEY,
  baseURL: "https://<YOUR_AI_PROXY_BASE_URL>/v1",
});

From here, you can incrementally:

• Introduce model aliases (e.g., “general-purpose”) and test provider swaps
• Enable caching for static/deterministic routes
• Set per-route limits and timeout policies in the proxy

Running the AI Proxy on Sealos

If you build on Sealos, you benefit from a cohesive platform for your entire AI stack:

• Deploy the proxy as an app within your Sealos environment
• Co-locate RAG components (vector DBs, retrievers), your API services, and the proxy
• Use Sealos’ container-native tooling to scale horizontally, set resource limits, and manage upgrades
• Integrate with your observability stack and secret management

Start by exploring Sealos at https://sealos.io to learn about the platform’s app store, multi-tenant isolation, and operational tooling that make running an AI proxy straightforward.

Troubleshooting and Tips

• Cache misses you expected to be hits:

  • Check for differences in temperature, top_p, or message ordering.
  • Ensure system prompts are identical across requests.
  • Verify that model alias and request parameters match exactly.

• Stale answers:

  • Reduce TTLs or version your prompts/content.
  • Invalidate caches on data changes.

• Inconsistent outputs after provider switch:

  • Align sampling parameters across providers.
  • Use stricter prompts; some models interpret loosely worded instructions differently.
  • Keep a regression set to test correctness when changing routes.

• Rate limit errors (429):

  • Configure per-project or per-route throttles.
  • Implement retries with exponential backoff.
  • Consider a burst queue for spiky traffic.

• Streaming issues:

  • Ensure your client supports SSE and you’re not buffering the entire response inadvertently.
  • If you cache streaming results, cache only the final assembled text to avoid chunk boundary issues.

Frequently Asked Questions

• Is the Sealos AI Proxy OpenAI-compatible?

  • Yes. You’ll typically just change the base URL to the proxy and use a proxy-issued key. Refer to the proxy’s documentation for any provider-specific nuances.

• Can I route to multiple providers?

  • Yes. The proxy is designed to connect to multiple upstreams and select based on your policies (cost, latency, region, or fallback).

• How do I control costs?

  • Use caching for deterministic prompts, choose smaller models where acceptable, and monitor cost per request in proxy metrics. Set quotas per project to avoid budget overruns.

• Will caching leak sensitive data?

  • It shouldn’t if you configure it correctly. Use per-project caches, avoid caching PII, or enable encryption at rest with strict access controls. When in doubt, disable caching on sensitive routes.

• Do I need to rewrite my app?

  • In most cases, no. OpenAI-compatible integration keeps code changes minimal. You can roll out proxy usage route-by-route.

A Checklist for Production Readiness

• Use proxy-issued keys and remove provider keys from app config
• Set base URL to the AI proxy and test non-streaming + streaming flows
• Choose cacheable routes and set conservative TTLs
• Add versioning to prompts and RAG content
• Configure rate limits, timeouts, and retries
• Establish dashboards for latency, cost, token usage, and cache hit rate
• Define provider routing policies and fallbacks
• Document your data retention and redaction policies
• Run a correctness regression suite when changing models/providers

Conclusion

LLM-powered apps succeed when they’re fast, affordable, and reliable—qualities that are hard to achieve if every service talks to model providers directly. The Sealos AI Proxy centralizes that complexity: it gives you one OpenAI-compatible endpoint, powerful caching, smart routing, robust limits, and end-to-end observability. You get lower latency, lower cost, and the freedom to change providers or prompts without reinventing your entire stack.

Whether you’re running a high-volume chatbot, a RAG system, or large batch jobs, the proxy is a practical foundation that scales with your needs. And if you’re deploying on Sealos, you can run the proxy alongside your data stores and applications, benefiting from Kubernetes-native isolation and tooling.

Start with a simple integration—change the base URL and key—then iterate: introduce caching where it makes sense, add provider fallbacks, and monitor outcomes. With the Sealos AI Proxy as your AI gateway, you can focus on product quality and business impact, not on wrangling SDKs, keys, and rate limits.