Helicone vs Vigil
What Helicone does and what Vigil does, side by side. Every Helicone fact below was read on Helicone's own pages on 2026-10-09 and links to the page it came from; a feature its pages do not mention is marked “not stated”, never “no”. Where Helicone is stronger, this page says so.
What Helicone is, and what Vigil is
Helicone, in its own words: “Open source LLM observability platform. One line of code to monitor, evaluate, and experiment.”github.com. Both: a gateway (base URL https://ai-gateway.helicone.ai) in the request path, or async logging outside it.
Vigil is a proxy for AI API calls. Change one base URL, add one header, and every call is logged with its cost, tokens, latency, errors and agent, then forwarded unchanged. Where the provider supports explicit prompt caching, Vigil can place the cache markers itself when optimisation is switched on. It stores no prompt text and caches no responses.
- Helicone says: "Helicone doesn’t run evaluations for you - we’re not an evaluation framework."docs.helicone.ai
- Helicone says: in async mode, caching, custom rate limiting and retries are not available (the proxy-versus-async table).docs.helicone.ai
Feature by feature
The Helicone column was read on Helicone's own pages on 2026-10-09; each cell links to the page. “Not stated” means the pages read do not mention it, which is not the same as “no”. The Vigil column is read from Vigil's code and docs.
| Feature | Helicone | Vigil |
|---|---|---|
| Integration | Gateway base URL, or async logging: "the actual logging of the event is not on the critical path".docs.helicone.ai | Proxy. Change the base URL and add the X-Vigil-Key header; no SDK. |
| Open source | Yes, Apache-2.0.github.com | No. Vigil is not open source. |
| Hosting | Cloud (US or EU region) and self-host (Docker Compose, Helm, AWS).docs.helicone.ai | Cloud only: a Cloudflare Worker in front of the provider, a dashboard on Vercel, data in Supabase (Frankfurt, EU). |
| Cost per call | Yes; "Cost, latency, and quality metrics", an LLM Cost API covering "300+ models and providers".github.com | Yes: cost, tokens, latency, status and agent on every call, from a rate registry where every rate carries its source, date and provenance; a dash where no rate is published. |
| Providers | "Access 100+ AI models with 1 API key through the OpenAI API".docs.helicone.ai | 17 providers routed by segment. |
| Prompt caching | Passes your markers through: on Anthropic "You add cache_control yourself"; automatic provider caching on OpenAI-compatible models is reported.docs.helicone.ai | Creates cache hits: Anthropic, Google Vertex, Mistral get cache markers placed by Vigil when optimisation is on; AWS Bedrock when the request carries an API key rather than a SigV4 signature. On other providers Vigil records the provider’s own caching. |
| Response caching | Yes, its own exact-match cache (Helicone-Cache-Enabled), stored in Cloudflare Workers KV, up to 365 days.docs.helicone.ai | No. Vigil does not cache responses. |
| Routing and fallbacks | "Routes to the cheapest provider first"; "Instantly tries the next provider on errors".docs.helicone.ai | Model routing is in beta: Sends a conversation to a cheaper model from the same provider — one tier down — when its opening's size and tools are in a band the agent's routing level covers and the cheaper model can take the request; every call of the conversation gets the same answer. No provider fallbacks or load balancing. |
| Prompt management | README lists "Prompt management with versioning"; the docs pages for it returned 404 on the day read.github.com | No prompt management or versioning. |
| Evals | Scores API only: "we’re not an evaluation framework".docs.helicone.ai | No evaluations. A score can be sent for a call through the feedback endpoint. |
| Tracing | "Observability for traces and sessions".github.com | One record per call. No spans or traces. |
| Alerts | Error-rate and cost alerts by email and Slack.docs.helicone.ai | Cost spikes, failures and findings are flagged in the dashboard. Nothing is sent by email, Slack or push. |
| Prompt injection and PII | Prompt injection: Meta’s Prompt Guard model, "Blocks detected threats", "OpenAI models only". PII detection: not stated.docs.helicone.ai | Flags likely prompt injections and personal data in prompts, on every plan. Nothing is blocked or redacted. |
| Budgets and rate limits | Yes: a rate-limit policy header, with a cents unit that caps spend per window.docs.helicone.ai | No spend caps or rate limits on your provider traffic. Optimisation can be switched off per agent. |
| Seats | Hobby 1 seat; Pro and above unlimited; SAML SSO on Enterprise.helicone.ai | Seats per plan: 1 on Free, 3 on Plus, unlimited from Pro. Teammates are invited; there are no role tiers. |
| Compliance | "Helicone is SOC 2 compliant and the report is available upon request"; HIPAA on the Team tier.docs.helicone.ai | No SOC 2 or ISO 27001 report. A DPA is published. |
| Data residency | "Choose between EU and US regions".docs.helicone.ai | Account and telemetry stored in the EU (Supabase, Frankfurt). The proxy runs on Cloudflare’s edge. No prompt text or responses are stored. |
Where Helicone is stronger
- Open source under Apache-2.0, and self-hostable.
- A response cache, provider fallbacks and cost-based routing across 100+ models.
- Spend caps and rate limits per user or property, in the request path.
- Email and Slack alerts, traces and sessions, a US or EU region, and a SOC 2 report.
Where Vigil differs
- It creates prompt-cache hits rather than reporting them, on the providers whose caching lets a proxy place markers, and measures what caching would have saved on the others.
- Every rate it prices with carries its source, its retrieval date and a provenance label, and a cost it cannot stand behind is a dash, not a number.
- Monitoring is not gated by plan: every agent, every provider, on Free. Paid plans switch optimisation on.
- It does less: no response cache, no evals, no prompt management, no traces, no alerts outside the dashboard.
Pricing, side by side
Heliconehelicone.ai
- Hobby Free: 10,000 requests, 1 GB storage, 1 seat, 7-day retention
- Pro $79/mo: 10K requests and 1 GB free, then usage-based; unlimited seats, alerts, 1-month retention
- Team $799/mo: everything in Pro, 5 organisations, SOC-2 and HIPAA, 3-month retention
- Enterprise Contact: SAML SSO, on-prem, configurable retention
The per-request and per-GB rates past the included amounts were not visible on the page read.
Vigil vigil.tools/pricing
- Free $0: every agent monitored; 10,000 logged calls a month, 7 days of history; every optimisation On during your 7-day trial, as Plus, then Shadow only
- Plus $29/mo: every optimisation On up to $100 saved a billing month, then Shadow until the next; 500,000 logged calls, 30 days
- Pro $99/mo: every optimisation On up to $500 saved a billing month, then Shadow until the next; 2,000,000 logged calls, 90 days
- Supreme $299/mo: every optimisation On up to $2,000 saved a billing month, then Shadow until the next; Unlimited logged calls, 365 days
- Enterprise Custom: by contract
Monthly, excl. VAT. Monitoring is free on every plan; what a paid plan buys is a higher limit on the money Vigil saves you per billing month before optimisations go to Shadow.
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