← Vetro Attest · Free Art. 12/14 checker · Free EU AI Act tools

Vetro Attest vs. Helicone

*Engineering comparison, not legal advice. Helicone features change quickly; check their documentation for the current state.*

Helicone and Vetro Attest do different jobs. Helicone helps you see and improve what your LLM application does. Vetro Attest turns a trace you already have into evidence that someone outside your company can check.

What Helicone does well

Helicone is an open-source LLM observability platform built around a proxy: you point your OpenAI, Anthropic or other provider base URL at Helicone (or use its async logging), and every request and response is logged without touching your call sites. Teams use it to:

• Log and search every LLM request with latency, token usage and cost, per user, per session and per custom property;
• Group agent runs into sessions so a multi-step workflow reads as one trace;
• Operate the gateway: caching, rate limits, retries and provider fallbacks in the request path;
• Manage prompts and attach scores or evaluations to logged requests.

It is available as a managed cloud and self-hosted. For seeing cost and behaviour across providers with one line of setup, it is a strong choice.

What an observability tool does not give you

Evidence for a regulator, an auditor or a customer must convince someone who does not trust you.

• The operator controls the data. Whoever runs the instance, you when self-hosted, a vendor you pay in the cloud case, can in principle edit or delete stored logs, so an export is a claim, not proof.
• A gateway sees requests, not decisions. A proxy records what went to and came back from the model. Tool calls, policy checks and human overrides that happen in your code are only there if you send them as extra data.
• No independent timestamp or signature. An export shows what the database held when you exported it, not that it looked the same at the time of the incident.
• No mapping onto the AI Act. Logging duties (Art. 12, 19, 26) ask what the logs make traceable, not only what they contain.

None of this is a flaw in Helicone; it is outside what the tool is for.

What Vetro Attest adds

Vetro Attest accepts an OTLP/JSON trace with the OpenTelemetry GenAI semantic conventions, rebuilds it into a hash-chained ledger and checks it for free. For 29 USD, one-off, you get:

• a full EU AI Act report (Markdown and HTML) mapping the trace onto logging obligations;
• an ed25519 countersignature over the digest, event count and timestamp, verifiable by anyone against our published public key, no account needed.

The countersignature attests that the trace verified at a time. It does not attest that the events are true; the report is a structured aid, not legal advice or certification.

When to use both

• Keep Helicone in the request path for logging, cost tracking, caching and fallbacks.
• When a run matters, export its trace as OTLP/JSON and get it countersigned. Store the attestation next to the trace.
• On an audit or dispute, hand over the trace plus the attestation.

Helicone tells you what your agent did. The countersignature lets someone else believe it.

Try it

• Run the free EU AI Act Art. 12/14 checker.
• Paste an OTLP trace on the Vetro Attest home page and verify it free. The full report plus countersignature is 29 USD, no subscription.

See a sample ledger verified in one click, check your own logs free or get the countersigned EU AI Act report.