LLM API usage is becoming one of the fastest‑growing expenses in modern software infrastructure. Even a single production workflow can generate thousands of dollars per month in token usage, and when multiple teams, providers, and applications are involved, spend quickly becomes unpredictable.
The root cause is architectural. When applications call providers directly, there is no shared layer to enforce budgets, cache repeated requests, route traffic to cheaper models, or track where tokens are actually being consumed.
An AI gateway solves this by sitting between applications and model providers, adding routing, caching, rate limits, and budget enforcement in one place. This guide reviews five of the best AI gateways for monitoring and controlling LLM costs in 2026.
1. Bifrost
Bifrost is an open‑source AI gateway built in Go that provides one of the most complete cost‑control toolkits available today. It connects to 20+ providers through a single OpenAI‑compatible API and enforces cost policies in real time before requests reach the provider.
Cost control features
- Hierarchical budget management across Customer, Team, Virtual Key, and Provider levels, with hard limits that block requests when budgets are exceeded
- Virtual keys for isolating usage per team, project, or customer
- Semantic caching to avoid repeated calls for similar prompts
- Automatic failover between providers to avoid wasted retries
- Built‑in observability with Prometheus metrics for real‑time cost dashboards
- Intelligent load balancing across providers and API keys
- Token and request‑level rate limits aligned with provider billing
Bifrost adds only microseconds of overhead at high throughput and can be started quickly with npx -y @maximhq/bifrost. Because it is open source, teams can deploy it without licensing costs while still getting enterprise‑grade controls.
Best for: Teams that need real‑time budget enforcement, semantic caching, and detailed cost attribution across multiple applications.
2. Cloudflare AI Gateway
Cloudflare AI Gateway provides a managed proxy layer that runs on Cloudflare’s edge network and offers basic visibility into LLM usage.
Strengths
- Edge caching for identical requests
- Usage analytics dashboard
- Rate limiting per consumer
- Free tier available
Limitations
No semantic caching, no hierarchical budgets, and limited per‑team attribution. It works well as a proxy but not as a full cost governance layer.
Best for: Teams already using Cloudflare that want simple observability and caching.
3. LiteLLM
LiteLLM is an open‑source proxy and Python library that standardizes access to many providers while adding basic cost tracking.
Strengths
- Spend tracking per key
- Budget limits per project
- Support for many providers
- Self‑hosted deployment
Limitations
Higher latency at scale due to Python runtime constraints and limited enterprise governance features without the paid version.
Best for: Development workflows that need lightweight spend tracking.
4. Kong AI Gateway
Kong AI Gateway extends Kong’s API management platform to LLM traffic, allowing organizations to apply existing governance patterns to AI workloads.
Strengths
- Token‑based rate limiting
- Model‑level limits
- Semantic caching
- Enterprise analytics
Limitations
Requires existing Kong infrastructure and most advanced features are in the enterprise tier.
Best for: Enterprises already running Kong.
5. AWS Bedrock
AWS Bedrock provides built‑in cost controls for workloads running inside the AWS ecosystem.
Strengths
- Provisioned throughput pricing
- CloudWatch monitoring
- IAM‑based access control
- Service quotas
Limitations
Limited to AWS models, no semantic caching, and no unified control across external providers.
Best for: AWS‑native deployments.
Choosing the Right Gateway
Different teams need different levels of cost control.
- Real‑time enforcement → Bifrost
- Edge proxy → Cloudflare
- Python workflows → LiteLLM
- Existing Kong stack → Kong
- AWS‑only workloads → Bedrock
LLM costs grow quickly, and monitoring alone is not enough. The gateway layer must enforce budgets, route intelligently, and provide visibility across every request.
Ready to control LLM spend? Book a Bifrost demo
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