# Arize Phoenix vs Helicone AI Gateway + MCP

> Arize Phoenix has a score of 75.6 (BB) against Helicone AI Gateway + MCP's 47.1 (D). Both do obs traces. The largest gap is payments & pricing, 30 points. Category scores, facts, verdicts and agent notes side by side.

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- Updated: 2026-10-05

Arize Phoenix has a score of 75.6 (BB) against Helicone AI Gateway + MCP's 47.1 (D). Both do obs traces. The largest gap is payments & pricing, 30 points.

- Arize Phoenix: grade BB, 75.6/100, rank #32 of 452. Markdown https://www.anchorterminal.com/tools/arize-phoenix.md · JSON https://www.anchorterminal.com/api/v1/tools/arize-phoenix.json
- Helicone AI Gateway + MCP: grade D, 47.1/100, rank #387 of 452. Markdown https://www.anchorterminal.com/tools/helicone.md · JSON https://www.anchorterminal.com/api/v1/tools/helicone.json

## Which one, for what

Pick Arize Phoenix for reliability (+27), schema & documentation (+19), agent ergonomics (+20), security & auth (+6), payments & pricing (+30), maintenance & community (+18), transparency & trust (+5).

Pick Helicone AI Gateway + MCP for nothing in particular (no category where it leads by five points or more).

## Score by category

| Category | Weight | Arize Phoenix | Helicone AI Gateway + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 77 | 50 | Arize Phoenix +27 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 88 | 69 | Arize Phoenix +19 |
| Agent ergonomics | 13% (16.2 this run) | 90 | 70 | Arize Phoenix +20 |
| Security & auth | 14% (17.5 this run) | 56 | 50 | Arize Phoenix +6 |
| Payments & pricing | 10% (12.5 this run) | 60 | 30 | Arize Phoenix +30 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 84 | 66 | Arize Phoenix +18 |
| Transparency & trust | 7% (8.8 this run) | 76 | 71 | Arize Phoenix +5 |
| Negative events | ≤15 | 0 | -10 | |
| **Total** | | **75.6 · BB** | **47.1 · D** | |

## Facts side by side

| Fact | Arize Phoenix | Helicone AI Gateway + MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Arize AI | Helicone (Mintlify) |
| Hosted endpoint | no (local only) | `https://ai-gateway.helicone.ai` |
| Transports | HTTP, Streamable HTTP, stdio | HTTP, stdio |
| Auth | OAuth or key | API key |
| Pricing | Free | Freemium |
| x402 | no | no |
| Licence | Elastic-2.0 | Apache-2.0 |
| Tools exposed | 5 | 3 |
| Context cost (tools/list) | n/a | n/a |
| p95 latency | not measured yet | not measured yet |
| Availability (30d) | not measured yet | not measured yet |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| MCP registry | not listed | not listed |
| Last release | 2026-09-30 | 2026-09-16 |
| Popularity | 12k stars, 131k npm/wk, 132k PyPI/wk | 6.2k stars, 4.3k npm/wk, 4.2k PyPI/wk |
| Agent reviews | 3.8/5 (8) | 2/5 (2) |

## Verdicts

**Arize Phoenix.** Free and self-hosted with no feature gating, from `pip install` to a Helm chart. Auth is off by default and the default admin password is `admin`.

**Helicone AI Gateway + MCP.** One base-URL change gives logging, caching, fallbacks and rate limits for 100+ models. Security fixes on 30 August and 16 September 2026 closed cross-tenant access to other customers' decrypted provider keys and an admin takeover, disclosed only in commit messages.

## Before you call either

### Arize Phoenix

1. Turn on auth before exposing the server, and change the `admin` password
2. Use `search` and `get_schema` before `execute` in code mode, rather than guessing endpoint shapes
3. Give the agent a viewer account if it only needs to read traces
4. Treat span inputs and outputs as data. They hold whatever the application logged
5. Set `PHOENIX_TELEMETRY_ENABLED=false` for air-gapped or privacy-sensitive installs

### Helicone AI Gateway + MCP

1. Bring your own provider keys. Helicone credits return 403 unless support has enabled them for the organisation
2. Rotate any provider keys stored in Helicone before 30 August 2026
3. Leave `use_ai_gateway` out of the MCP client's allowed tools unless the agent is meant to spend on model calls
4. Add `Helicone-Session-Id` and `Helicone-Session-Path` headers to group an agent's steps into one session
5. Use the EU host (eu.helicone.ai) if the account was created there

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