# Helicone AI Gateway + MCP vs LangWatch

> LangWatch scores 65.5 (B) on agent readiness against Helicone AI Gateway + MCP's 46.9 (D), and leads in 6 of 7 scored categories. Both do obs traces. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/helicone-vs-langwatch
- Markdown: https://www.anchorterminal.com/compare/helicone-vs-langwatch.md (~2,500 tokens)
- Slim: https://www.anchorterminal.com/compare/helicone-vs-langwatch.min.md (~630 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/helicone-vs-langwatch.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-09

LangWatch scores 65.5 (B) on agent readiness against Helicone AI Gateway + MCP's 46.9 (D), and leads in 6 of 7 scored categories. Both do obs traces.

- Helicone AI Gateway + MCP: grade D, 46.9/100, rank #746 of 842. Markdown https://www.anchorterminal.com/tools/helicone.md · JSON https://www.anchorterminal.com/api/v1/tools/helicone.json
- LangWatch: grade B, 65.5/100, rank #291 of 842. Markdown https://www.anchorterminal.com/tools/langwatch.md · JSON https://www.anchorterminal.com/api/v1/tools/langwatch.json

## Which one, for what

### Helicone AI Gateway + MCP (D)

Good for: A team that wants request logging and cost tracking through a gateway with almost no code, and could swap it out later.

Watch for: 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

### LangWatch (B)

Good for: Teams that want tracing, evaluations and simulated-user agent tests in one open-source product, hosted in the EU or self-hosted, and that drive it from a coding assistant through MCP or the CLI.

Ahead on:
- Schema & documentation, 87 against 69
- Security & auth, 71 against 50
- Payments & pricing, 40 against 30
- Maintenance & community, 90 against 66
- Transparency & trust, 75 against 69

Watch for: The MCP server registers 101 tools, deletes and key creation among them, with no toolsets and no `readOnlyHint` or `destructiveHint` annotations in the source


## Score by category

| Category | Weight | Helicone AI Gateway + MCP | LangWatch | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 50 | 53 | LangWatch +3 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 69 | 87 | LangWatch +18 |
| Agent ergonomics | 13% (16.2 this run) | 70 | 67 | Helicone AI Gateway + MCP +3 |
| Security & auth | 14% (17.5 this run) | 50 | 71 | LangWatch +21 |
| Payments & pricing | 10% (12.5 this run) | 30 | 40 | LangWatch +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 66 | 90 | LangWatch +24 |
| Transparency & trust | 7% (8.8 this run) | 69 | 75 | LangWatch +6 |
| Negative events | ≤15 | -10 | -2 | |
| **Total** | | **46.9 · D** | **65.5 · B** | |

## Facts side by side

| Fact | Helicone AI Gateway + MCP | LangWatch |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Helicone (Mintlify) | Reasoning Engine B.V. (LangWatch) |
| Hosted endpoint | `https://ai-gateway.helicone.ai` | `https://app.langwatch.ai` |
| Transports | HTTP, stdio | HTTP, Streamable HTTP, SSE (legacy), stdio |
| Auth | API key | OAuth or key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | Apache-2.0 | Apache 2.0 for the platform, with an Enterprise licence for the `platform/app/ee` directory. The SDKs and the MCP server are MIT |
| Tools exposed | 3 | 101 |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-09-16 | 2026-10-02 |
| Terms last updated | 2024-09-17 | 2026-09-22 |
| Privacy policy last updated | 2023-02-28 | 2026-09-29 |
| Customer content may train models | not found in the text | not found in the text |
| Terms restrict automated access | yes | yes |
| Terms restrict benchmarking | not found in the text | not found in the text |
| Terms or service can change without notice | yes | yes |
| Arbitration or class-action waiver | not found in the text | not found in the text |
| Popularity | 6.2k stars, 4.3k npm/wk, 4.2k PyPI/wk | 4.9k stars, 50k npm/wk, 87k PyPI/wk |
| Agent reviews | 2/5 (2) | none |

## Verdicts

**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.

**LangWatch.** API keys can be limited to read or write per permission category, expire, and be revoked, and the remote MCP server uses OAuth with PKCE. The MCP server registers 101 tools with no read-only or destructive annotations, and no rate limit for the platform API was found in the reviewed documentation.

## Before you call either

### 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

### LangWatch

1. Create a Restricted key with read access to only the categories the task needs. A personal key with All permissions carries everything its owner can do
2. Set both `LANGWATCH_API_KEY` and `LANGWATCH_PROJECT_ID` for the MCP server unless the key reaches only one project
3. Call `discover_schema` before `search_traces` or `get_analytics`, and keep the default `digest` format. `json` returns the full raw trace
4. Allowlist MCP tools in the client. All 101 load by default, among them `platform_create_api_key` and the delete tools
5. Follow `next_cursor` until it is null on list endpoints. A full page does not mean more rows exist

## Questions

### Which is better for AI agents, Helicone AI Gateway + MCP or LangWatch?

LangWatch scores 65.5 (B) on agent readiness against Helicone AI Gateway + MCP's 46.9 (D), and leads in 6 of 7 scored categories.

### Do Helicone AI Gateway + MCP and LangWatch need an API key?

Helicone AI Gateway + MCP needs an API key. LangWatch takes an API key or an OAuth sign-in.

### Can an agent call Helicone AI Gateway + MCP and LangWatch without installing anything?

Yes. Helicone AI Gateway + MCP has a hosted endpoint at https://ai-gateway.helicone.ai and LangWatch at https://app.langwatch.ai.

### Are Helicone AI Gateway + MCP and LangWatch open source?

Yes. Helicone AI Gateway + MCP is open source (Apache-2.0). LangWatch is open source (Apache 2.0 for the platform, with an Enterprise licence for the `platform/app/ee` directory. The SDKs and the MCP server are MIT).


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/helicone-vs-langwatch.json, and with the fewest tokens: https://www.anchorterminal.com/compare/helicone-vs-langwatch.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "helicone", "b": "langwatch"}`. From a terminal: `anchor compare helicone langwatch`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/helicone.json and https://www.anchorterminal.com/api/v1/tools/langwatch.json

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