How do I secure LLM API keys?

Never hardcode API keys. Use environment variables or secrets management services. Rotate keys regularly, use minimal scopes, and never expose them in client-side code.

What rate limiting strategies work for LLM APIs?

Implement token-based rate limiting (requests per minute), cost-based limits, per-user quotas, and tiered approaches. Use token estimation to predict costs before making requests.

LLM API Security

Best practices for securing LLM API endpoints - authentication, rate limiting, key management, and cost control

Updated: February 2026

LLM API Threat Landscape

API Key Exposure

Hardcoded keys in source code, client-side exposure, or leaked credentials

Rate Limit Abuse

Automated attacks consuming API quotas or causing denial of service

Cost Attacks

Prompt manipulation causing excessive token usage and unexpected costs

Data Leakage

Sensitive data in prompts or responses exposed through logs

Authentication Methods

API Keys

Generate unique keys per user/application
Use environment variables for storage
Rotate keys regularly (30-90 days)
Implement key revocation

OAuth 2.0

Implement for user-facing applications
Use short-lived access tokens
Implement refresh tokens
Proper scope definitions

JWT Tokens

Short expiration times
Strong signing algorithms
Proper claim validation
Token revocation support

Rate Limiting & Throttling

Token-Based Limits

Track input + output tokens
Set per-minute/per-day limits
Use sliding windows
Implement burst allowance

Cost Controls

Budget alerts (50%, 80%, 100%)
Per-user quotas
Token estimation before requests
Hard caps with circuit breakers

Tiered Approaches

Free tier: strict limits
Basic: moderate limits
Pro: higher limits
Enterprise: custom agreements

Provider Security Comparison

Provider	Key Features	Rate Limits	Security
OpenAI	GPT models, Assistants API	Tier-based RPM	SOC 2, API key management
Anthropic	Claude, tool use	Token-based	SOC 2, HIPAA available
Google	Gemini, Vertex AI	Project quotas	SOC 2, HIPAA, ISO
AWS Bedrock	Multiple models	Account-based	AWS IAM, VPC, encryption

Self-Hosted LLM Security

Network Isolation

Deploy in VPC/private network
Use firewall rules
No public internet access
VPN for management

API Security

Enable authentication
Use TLS/SSL
Implement API keys
Rate limiting

Model Protection

Model files encrypted at rest
Secure model loading
No model export
Access logging

Best Practices Checklist

Use environment variables for API keys
Rotate keys regularly
Implement rate limiting
Set cost alerts
Log API usage
Use HTTPS
Validate input
Sanitize output