# Sylica LLC

> Sylica is an OpenAI-compatible gateway to 100+ frontier LLMs. One API for OpenAI, Anthropic, xAI, Google, and leading open-source models — smart routing, fallbacks, streaming, prepaid credits, BYOK.

Sylica is a developer platform operated by Sylica LLC, a limited liability company organized under the laws of New Mexico, USA. It exposes one OpenAI-compatible endpoint in front of many frontier large language models. Instead of maintaining separate SDKs, keys, and retry policies for OpenAI, Anthropic, xAI, Google, and open-source model endpoints, teams point at sylicaai.com and swap models by changing the `model` field. Routing, streaming, fallbacks, and billing are handled by the gateway.

## Key facts

- Legal entity: Sylica LLC (New Mexico, USA)
- Canonical site: https://sylicaai.com
- API base URL: https://api.sylicaai.com/v1 (OpenAI-compatible)
- Auth header: `Authorization: Bearer sk-sylica-...`
- Supported providers: OpenAI, Anthropic, xAI (Grok), Google (Gemini), open-source and open-weights models
- Billing: prepaid credits in USD, pay-as-you-go, no monthly minimum; BYOK optional
- Compliance: SOC 2 Type II in progress, GDPR-ready DPA, subprocessor list published
- Active promotion: 30% off every model, auto-applied on every request (code LAUNCH30)

## Core pages

- [Homepage](https://sylicaai.com): product overview, hero demo, SDK snippets
- [Models](https://sylicaai.com/models): catalog of every model the gateway proxies, with live pricing and capabilities
- [Pricing](https://sylicaai.com/pricing): credit mechanics, pricing structure, quotas
- [Docs](https://sylicaai.com/docs): implementation guide
- [Blog](https://sylicaai.com/blogs): engineering writeups and launch posts
- [Careers](https://sylicaai.com/jobs): open internship roles (backend and frontend)
- [Compliance hub](https://sylicaai.com/compliance): privacy, terms, DPA, subprocessors, security, cookies

## Documentation

- [Overview](https://sylicaai.com/docs/overview): Platform architecture, compatibility model, and request lifecycle.
- [Quickstart](https://sylicaai.com/docs/quickstart): Production-ready setup path for your first successful request.
- [Authentication](https://sylicaai.com/docs/authentication): API key lifecycle, header requirements, and key management policy.
- [Endpoints](https://sylicaai.com/docs/endpoints): Core REST surface for chat, model catalog, and credits.
- [Chat Completions](https://sylicaai.com/docs/chat-completions): Request contract, response shape, and advanced controls.
- [Streaming](https://sylicaai.com/docs/streaming): SSE protocol behavior, chunk semantics, and client handling.
- [Routing](https://sylicaai.com/docs/routing): Provider routing controls, fallback behavior, and latency strategy.
- [Errors and Retries](https://sylicaai.com/docs/errors-retries): Error taxonomy, retry classes, and resilient backoff guidance.
- [Billing and Credits](https://sylicaai.com/docs/billing-credits): Credit checks, debit timing, and balance observability patterns.
- [Production Readiness](https://sylicaai.com/docs/production-readiness): Deployment checklist for security, reliability, and supportability.

## Blog posts

- [The OpenAI-Compatible Gateway Pattern: Why Teams Need One LLM API](https://sylicaai.com/blogs/openai-compatible-gateway-pattern): A practical argument for putting one stable OpenAI-compatible contract in front of a fast-changing model market.
- [Smart Routing for LLMs: Balancing Cost, Speed, and Quality](https://sylicaai.com/blogs/smart-routing-for-llms-cost-speed-quality): Smart routing is not magic. It is a clear policy system that maps workload intent to the best available model path.
- [How to Design Fallbacks Without Breaking Streaming Responses](https://sylicaai.com/blogs/fallback-routing-without-breaking-streaming): Fallbacks can improve reliability, but only if the gateway respects the moment when a streamed response becomes irreversible.
- [BYOK for AI Products: Security, Cost Control, and Trust](https://sylicaai.com/blogs/byok-for-ai-products-security-cost-control-trust): Bring-your-own-key is not just a billing option. It changes how customers evaluate security, ownership, and operational control.
- [A Practical Guide to LLM Cost Accounting and Token Metering](https://sylicaai.com/blogs/llm-cost-accounting-token-metering-guide): Token accounting needs to be accurate enough for billing, fast enough for product UX, and transparent enough for operators.
- [Building a Model Playground That Engineers Actually Use](https://sylicaai.com/blogs/building-a-model-playground-engineers-use): A useful playground should make model comparison fast, honest, and connected to the same gateway path production uses.
- [Multi-Provider AI in Production: Lessons from Gateway Architecture](https://sylicaai.com/blogs/multi-provider-ai-production-gateway-architecture): Production multi-provider AI needs adapters, shared schemas, route policy, observability, and operational boundaries.
- [Prepaid Credits for AI APIs: A Better Billing Model for Builders](https://sylicaai.com/blogs/prepaid-credits-ai-api-billing-model): Prepaid credits can reduce billing surprise, simplify onboarding, and make usage visible when paired with a precise ledger.
- [Choosing Between Frontier and Open-Source Models in One Workflow](https://sylicaai.com/blogs/frontier-vs-open-source-models-one-workflow): The right model is workload-specific. A gateway makes it easier to compare frontier and open-source options without changing application code.
- [From Prototype to Production: The LLM Gateway Launch Checklist](https://sylicaai.com/blogs/llm-gateway-launch-checklist-production): A checklist for teams moving from a direct model call to a reliable gateway-backed production launch.
- [Request Ledger Observability for LLM Apps](https://sylicaai.com/blogs/request-ledger-observability-for-llm-apps): A request ledger gives teams the operational memory they need to debug quality, latency, spend, and provider behavior.
- [Launching Sylica v1: OpenAI-Compatible Multi-Provider Routing](https://sylicaai.com/blogs/launching-sylica-v1): Sylica v1 brings one OpenAI-compatible API across OpenAI, Anthropic, xAI, Google, and open-source models with built-in fallbacks and credit metering.
- [How Fallback Routing Works in Sylica](https://sylicaai.com/blogs/how-sylica-fallbacks-work): A practical walkthrough of how Sylica handles retryable failures and preserves streaming semantics.
- [BYOK Security Model: How Sylica Stores Provider Keys](https://sylicaai.com/blogs/byok-security-model): A concise overview of BYOK encryption, key lifecycle, and operational safeguards in Sylica.

## API quickstart

Use any OpenAI SDK with the Sylica base URL:

```ts
import OpenAI from "openai";

const client = new OpenAI({
  baseURL: "https://api.sylicaai.com/v1",
  apiKey: process.env.SYLICA_API_KEY,
});

const response = await client.chat.completions.create({
  model: "anthropic/claude-sonnet-4.5",
  messages: [{ role: "user", content: "Hello" }],
});
```

Meta-models for routing:
- `sylica/auto`: balanced quality/cost
- `sylica/cheapest`: optimize for price
- `sylica/fastest`: optimize for latency

## Contact

- General: hello@sylicaai.com
- Privacy: privacy@sylicaai.com
- Security: security@sylicaai.com
- Legal: legal@sylicaai.com