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Helicone is an observability platform. It sits in front of your LLM calls and gives you logging, request tracing, dashboards, caching, and prompt tooling — built to help engineers debug and improve what their AI is doing.
TOLVYN is a financial control plane. It sits in the same place — a proxy in front of your providers — but its job is governance of spend: per-request cost attribution, an immutable audit ledger, and budgets that actually block requests before the provider is called. Different question: not "what did my AI say?" but "who spent what, can I prove it, and can I stop it?"
They overlap at the proxy, and plenty of teams run both. This page is an honest read on where each one is the right tool — including where Helicone is clearly ahead.
| Capability | TOLVYN | Helicone |
|---|---|---|
| Primary purpose | Financial control plane — cost governance & audit | Observability — logging, tracing, debugging |
| Provider coverage | OpenAI, Anthropic, Google | 100+ providers |
| Request & response logging | Metadata only — prompts/responses never stored | Full request/response logs (its core strength) |
| Response caching | Not offered | Yes |
| Prompt management & experiments | Not offered | Yes |
| Cost & token metering | Provider-reported tokens, microdollar precision | Yes |
| Cost-attribution breakdown views | By model, team, service, user, end customer | By user, properties, sessions |
| Immutable audit ledger (hash-chain + HMAC + verify) | Yes | No |
| Budget enforcement that blocks before the provider call | Hard budgets, per-plan quotas, scoped kill switch | Alerts & rate limits |
| Export (request log + ledger CSV) | Yes | Yes |
| Migration-header compatibility | Reads Helicone-* and X-Portkey-* headers |
— |
| SDKs | Python, Node, Go, CLI | Broad SDK & framework coverage |
| Self-hosting | Single Go binary + PostgreSQL | Yes (Docker / Helm) |
| Maturity & ecosystem | Newer, narrower scope | Mature, large community |
If your bottleneck is seeing and debugging requests across many providers, Helicone is the more complete product today. If your bottleneck is proving and controlling spend, that's the gap TOLVYN was built for.
In March 2026, Helicone announced it was joining Mintlify. According to the company's own announcements, the open-source project moved into maintenance mode following the acquisition. We're not going to characterize what that means for their roadmap — read it from the source: Helicone's own announcements and their open-source repository.
We mention it for one practical reason: if you're choosing an LLM gateway today, the maintenance trajectory of whatever sits in your request path is a real factor. Verify it for yourself against their channels above — don't take a competitor's word for it.
Observability tools tell you what happened. TOLVYN gives you a record you can prove wasn't altered. Every metered request writes one ledger entry, and the entries are chained.
Each ledger record is hash-chained (SHA-256) and signed with HMAC-SHA256 using a per-tenant
key. Sequence numbers are allocated under a Postgres advisory lock per tenant — no gaps, no
duplicates, even under concurrent writes. Anyone can re-derive the chain and pinpoint the
first tampered record with tolvyn ledger verify. The ledger entry is
written in the same transaction as the request it accounts for, so there are no orphaned or
partial records.
That's what turns "our dashboard says we spent $X" into evidence a finance team or auditor can actually rely on. No mainstream observability tool ships a tamper-evident cost ledger — it's a different design goal.
Not mutually exclusive: because TOLVYN reads Helicone-* attribution
headers, teams already instrumented for Helicone can point traffic at TOLVYN for cost control
without re-tagging their requests.
Switching is a base-URL change plus a TOLVYN key — the proxy accepts
Authorization: Bearer, x-api-key, or
x-goog-api-key, and it understands your existing
Helicone-User-Id and properties so your attribution carries over.