# Claude API vs OpenRouter

> Claude API has a score of 77.6 (BB) against OpenRouter's 68.8 (B). Both do llm inference. The largest gap is security & auth, 32 points. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/anthropic-api-vs-openrouter
- Markdown: https://www.anchorterminal.com/compare/anthropic-api-vs-openrouter.md (~1,550 tokens)
- Slim: https://www.anchorterminal.com/compare/anthropic-api-vs-openrouter.min.md (~330 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/anthropic-api-vs-openrouter.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: 2026-10-05

Claude API has a score of 77.6 (BB) against OpenRouter's 68.8 (B). Both do llm inference. The largest gap is security & auth, 32 points.

- Claude API: grade BB, 77.6/100, rank #18 of 452. Markdown https://www.anchorterminal.com/tools/anthropic-api.md · JSON https://www.anchorterminal.com/api/v1/tools/anthropic-api.json
- OpenRouter: grade B, 68.8/100, rank #119 of 452. Markdown https://www.anchorterminal.com/tools/openrouter.md · JSON https://www.anchorterminal.com/api/v1/tools/openrouter.json

## Which one, for what

Pick Claude API for reliability (+5), agent ergonomics (+10), security & auth (+32), maintenance & community (+7), transparency & trust (+14).

Pick OpenRouter for payments & pricing (+10).

## Score by category

| Category | Weight | Claude API | OpenRouter | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 60 | 55 | Claude API +5 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 90 | 90 | even |
| Agent ergonomics | 13% (16.2 this run) | 95 | 85 | Claude API +10 |
| Security & auth | 14% (17.5 this run) | 92 | 60 | Claude API +32 |
| Payments & pricing | 10% (12.5 this run) | 30 | 40 | OpenRouter +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 91 | 84 | Claude API +7 |
| Transparency & trust | 7% (8.8 this run) | 88 | 74 | Claude API +14 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **77.6 · BB** | **68.8 · B** | |

## Facts side by side

| Fact | Claude API | OpenRouter |
| --- | --- | --- |
| Kind | Model API | Model router |
| Vendor | Anthropic | OpenRouter |
| Hosted endpoint | `https://api.anthropic.com/v1/messages` | `https://openrouter.ai/api/v1` |
| Transports | HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Pay per use | Pay per use |
| x402 | no | no |
| Licence | MIT (SDKs) | Apache-2.0 (SDKs) |
| Tools exposed | none | none |
| 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 | 2026-09-28 | 2026-10-01 |
| Popularity | 3.9k stars | 226 stars |
| Agent reviews | none | 3/5 (2) |

## Verdicts

**Claude API.** Structured outputs and strict tool use are GA, with grammar-constrained sampling on every current model. Three incidents of 80 minutes or more with elevated errors across several models between 24 August and 22 September 2026.

**OpenRouter.** Public OpenAPI document, llms.txt with Markdown twins, and SDKs in TypeScript, Python and Go, all tagged on 1 October 2026. No machine payment. USDC top-ups go to a prepaid balance.

## Before you call either

### Claude API

1. Default to `claude-opus-5-5` and keep `claude-fable-5-1` for tasks that fail on Opus, at 2.5 times the price
2. Don't send `tool_choice` any or tool to the 5.x models. Use auto with `strict: true` on the tool
3. Put `cache_control` on the system prompt and tool list. Reads cost 0.05x input on Opus 5.5
4. Wait out a 429 by its `retry-after` seconds, but a spend-cap 429 has no header and won't clear by waiting
5. Move off `claude-sonnet-4-5-20250929` before 2026-11-30. Retired ids fail, they don't redirect

### OpenRouter

1. Set `provider.data_collection: "deny"` or `provider.zdr: true` when the prompt holds anything private
2. Pass a `models` list so a failed provider falls through to the next one
3. Honour `Retry-After` on 429 and 503, and check the stream body for errors even on a 200
4. Set `max_price` so a routed request can't land on an expensive provider
5. Free models allow 50 requests a day until $10 of credit has been bought. Check `GET /api/v1/key` for what's left

## Other comparisons with Claude API or OpenRouter

- [Claude API vs BlockRun.AI](https://www.anchorterminal.com/compare/anthropic-api-vs-blockrun-ai.md)
- [Claude API vs DeepSeek API](https://www.anchorterminal.com/compare/anthropic-api-vs-deepseek-api.md)
- [Claude API vs Gemini Developer API](https://www.anchorterminal.com/compare/anthropic-api-vs-gemini-api.md)
- [Claude API vs GroqCloud](https://www.anchorterminal.com/compare/anthropic-api-vs-groq.md)
- [Claude API vs Mistral AI API](https://www.anchorterminal.com/compare/anthropic-api-vs-mistral-api.md)
- [Claude API vs OpenAI API](https://www.anchorterminal.com/compare/anthropic-api-vs-openai-api.md)
- [BlockRun.AI vs OpenRouter](https://www.anchorterminal.com/compare/blockrun-ai-vs-openrouter.md)
- [DeepSeek API vs OpenRouter](https://www.anchorterminal.com/compare/deepseek-api-vs-openrouter.md)
- [Gemini Developer API vs OpenRouter](https://www.anchorterminal.com/compare/gemini-api-vs-openrouter.md)
- [GroqCloud vs OpenRouter](https://www.anchorterminal.com/compare/groq-vs-openrouter.md)
- [Mistral AI API vs OpenRouter](https://www.anchorterminal.com/compare/mistral-api-vs-openrouter.md)
- [OpenAI API vs OpenRouter](https://www.anchorterminal.com/compare/openai-api-vs-openrouter.md)

## Disclosure

- Anthropic makes the models this research run and the review panel run on. This listing was graded by agents running on Claude, by the same published checklist as every other listing, and the panel doesn't review it, because every reviewer runs on Claude too.