Helicone API
Helicone LLM observability proxy — a drop-in proxy that intercepts LLM API calls (OpenAI, Anthropic, etc.) to log requests/responses, track costs, enable caching, rate limiting, and provide analytics dashboards with minimal code changes.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
SOC2 certified. TLS enforced. Open-source for self-hosting. Provider API keys transit but are not stored. No granular key scopes. EU data residency available. For strict compliance, self-hosted Helicone keeps all data on-premises.
⚡ Reliability
Best When
You want instant LLM observability (logs, costs, latency) with minimal code changes by adding a proxy URL and one header — no SDK instrumentation needed.
Avoid When
You need structured multi-step tracing, automated evaluations, or your data cannot pass through third-party proxy infrastructure.
Use Cases
- • Zero-code LLM logging — agents route OpenAI calls through oai.hconeai.com instead of api.openai.com with a Helicone-Auth header added, logging everything without changing business logic
- • Cost tracking — agents querying Helicone's REST API to get per-user or per-session LLM cost breakdowns for chargeback, budgeting, or billing alerts
- • Request caching — agents enabling Helicone's cache feature to return cached responses for identical prompts, reducing costs and latency for repeated queries
- • Rate limiting — agents configuring Helicone rate limits per user or API key to prevent runaway LLM usage without implementing custom rate limit logic
- • Quality monitoring — agents using Helicone feedback API to submit scores on LLM responses, building quality tracking dashboards over time
Not For
- • Providers not yet supported — Helicone primarily proxies OpenAI-compatible APIs; some providers require gateway configuration
- • Air-gapped or strict data residency — proxying through Helicone means LLM inputs/outputs pass through Helicone's servers; use self-hosted Helicone (open-source) for strict data control
- • Full LLM tracing/evaluation — Helicone is a proxy logger; for structured traces, evals, and datasets use LangSmith or Arize
Interface
Authentication
Helicone API key passed as Helicone-Auth header (Bearer token) in proxy requests. Same key used for REST API access to logs and analytics. Separate keys for different environments. No granular scopes — full account access per key.
Pricing
Request-based pricing. Free tier is generous for development. Retention period determines how far back you can query logs. Enterprise offers SOC2 report, SLA, and on-premises deployment.
Agent Metadata
Known Gotchas
- ⚠ Proxy adds 5-20ms latency per request — latency-critical applications may see measurable overhead from routing through Helicone's proxy layer
- ⚠ Custom properties (Helicone-Property-{Name} headers) must be set per-request — there is no global property configuration; agents must inject metadata headers consistently
- ⚠ Cache keys include the full request body — any variation in prompt (including whitespace) creates a cache miss; agents must normalize prompts before sending for cache hit rates
- ⚠ LLM credentials still passed through the proxy — Helicone never stores provider API keys, but they transit Helicone servers; evaluate trust posture accordingly
- ⚠ Free tier log retention is 1 day — agents relying on Helicone for compliance logging or audit trails must be on paid plans with adequate retention
Alternatives
Full Evaluation Report
Detailed scoring breakdown, competitive positioning, security analysis, and improvement recommendations for Helicone API.
Scores are editorial opinions as of 2026-03-06.