The question behind every LLM gateway evaluation
When you evaluate LLM infrastructure, one question decides more than the feature matrix: where does your spend control run? On the request path, where it can refuse a call — or off it, where it can only record what happened?
Helicone and nRouter sit on opposite sides of that line. This article compares them on the mechanics that matter for production: enforcement position, plan-gated governance, retention, BYOK, and cost shape. All pricing claims below are from the vendors' published pages (Helicone's checked 2026-08-23).
Enforcement position: observe vs refuse
Helicone offers a request-path proxy and an async logging SDK. The async path is the important one to understand: it records calls after they happen. By construction, nothing off the request path can refuse a request. If the guardrail you want lives on the path you're not using, no plan upgrade changes physics.
nRouter is an inline gateway — every request passes through it. Preflight checks (guardrails, budget enforcement) run before the provider call, so an exhausted budget returns 402/429 before a token is billed, and blocked guardrail requests cost zero credits.
from openai import OpenAI
# nRouter: OpenAI-compatible endpoint, one key
client = OpenAI(
base_url="https://api.nrouter.ai/v1",
api_key="nr-...",
)
resp = client.chat.completions.create(
model="openai/gpt-4o-mini",
messages=[{"role": "user", "content": "Summarize this thread."}],
)
The migration from Helicone's proxy is a baseURL swap plus dropping the provider key and Helicone-Auth header for a single nRouter key.
Plan-gated governance
On Helicone's published pricing, guardrails, custom rate limits, evals/scores, prompt management, sessions, and alerts all begin on Pro ($79/month). SOC-2 and HIPAA begin on Team ($799/month). Helicone ships these features — the difference is which plan they're on. The first time you need to block something rather than watch it, the answer is a plan change.
nRouter puts guardrails and hierarchical budgets (organization → team → user → key; Daily/Weekly/Monthly/lifetime; Block/Warn/Throttle) on every plan. The commercial lever is a flat 4% platform fee on credits. Entry: $5 minimum credit purchase, card required, no free tier.
Retention and BYOK
- Retention: Helicone Pro keeps logs 30 days; Team 90 days; Enterprise unlimited. nRouter keeps a ledgered spend history rather than session traces — good for cost questions, thin for debugging. Plan your exports: Helicone's API allows 60 calls/minute.
- BYOK: Helicone supports bring-your-own-key (your provider billing — credits and negotiated rates — stays intact) and a 0%-markup credits path. nRouter has no BYOK: one managed key, nRouter holds upstream credentials. Provider-granted credits and negotiated rates cannot be spent through nRouter. This is the architectural position, not a gap that closes.
Cost shape
Helicone Pro: $79/month. nRouter: 0% token markup + flat 4% platform fee on credits (note: nRouter's own pages describe the fee inconsistently — check the current pricing page for your plan). Compare all-in cost per million tokens for the models you actually call.
When to stay on Helicone
Be honest about the trade-offs. Stay on Helicone if you need: session replay, HQL trace querying, datasets, BYOK for provider credits/negotiated rates, Google models (nRouter doesn't serve them), or certified SOC-2/HIPAA today (nRouter's SOC 2 Type II is in progress). If your next three needs are guardrails, evals, and per-team budgets on every plan, the inline gateway wins.
Full sourced comparison — every claim on both sides traced to the vendors' own published pricing and docs: nRouter vs Helicone comparison