Helicone vs Phoenix (Arize)
Both are alternatives to LangSmith. Here's how they stack up — verified facts, no spin.
Also searched as Phoenix (Arize) vs Helicone — same comparison, one verdict.
Helicone
Gateway and observability in one — one integration instead of two.
Helicone is an Apache-2.0 AI gateway with logging, cost tracking and caching built into the routing layer, which makes it a genuine two-birds option: point your client at Helicone and you get both the gateway and the observability without instrumenting your application code at all. That proxy-based approach is the practical distinction — nothing to add to your codebase, at the cost of only seeing what passes through the proxy.
Phoenix (Arize)
Strong evaluation tooling — but read the licence before you build on it.
Phoenix is Arize's tracing and evaluation tool, and its evaluation workflow is among the best available: run experiments, score outputs against datasets, and inspect where a chain went wrong. It runs locally in a notebook or as a self-hosted service. The critical detail most listicles omit is the licence — Phoenix is Elastic License 2.0, which is source-available rather than open source. You may use and modify it, but you may not offer it to third parties as a hosted or managed service, and you may not circumvent its licence-key functionality.
Side by side
| Helicone | Phoenix (Arize) | |
|---|---|---|
| Sovereignty Score | 88 | 62 |
| Open source | Yes | No |
| Self-hostable | Yes | Yes |
| Local-first | Yes | Yes |
| License | Apache-2.0 | Elastic License 2.0 (source-available, not OSI open source) |
| Pricing | Free and self-hostable under Apache-2.0. Hosted service has a free tier of roughly 10,000 requests per month, with paid plans starting around $79/month. | Free to self-host under ELv2 for your own internal use. Arize's commercial platform is priced separately. |
Helicone edges it on the Sovereignty Score, but the right pick depends on the trade-offs below.
Helicone
Strengths
- +Apache-2.0, fully self-hostable
- +Proxy-based — no code instrumentation needed to start
- +Gateway and observability in one component
- +Real free tier on the hosted version for evaluating it
Trade-offs
- −Only sees traffic through the proxy — no visibility into internal agent steps
- −Weaker evaluation tooling than Langfuse or LangSmith
- −Smaller project (about 6k stars)
- −Adds a proxy hop to every model call
Phoenix (Arize)
Strengths
- +Excellent evaluation and experiment tooling — the strongest of this group
- +Runs locally, including straight from a notebook
- +Self-hostable, so traces stay in your infrastructure
- +Actively developed, with commits landing daily
Trade-offs
- −Elastic License 2.0 — source-available, NOT open source; you cannot offer it as a managed service
- −The licence restriction is a real constraint if your product is itself a platform
- −Score of 62 reflects the licensing limitation, not the engineering quality
- −Smaller community than Langfuse
Related alternative guides
Facts verified 2026-07-30. Licenses and pricing change — spotted something out of date? That's a correction we want.