# Claude API vs Gemini Developer API

> Claude API has a score of 77.6 (BB) against Gemini Developer API's 62 (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-gemini-api
- Markdown: https://www.anchorterminal.com/compare/anthropic-api-vs-gemini-api.md (~1,550 tokens)
- Slim: https://www.anchorterminal.com/compare/anthropic-api-vs-gemini-api.min.md (~380 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/anthropic-api-vs-gemini-api.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 Gemini Developer API's 62 (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
- Gemini Developer API: grade B, 62/100, rank #223 of 452. Markdown https://www.anchorterminal.com/tools/gemini-api.md · JSON https://www.anchorterminal.com/api/v1/tools/gemini-api.json

## Which one, for what

Pick Claude API for reliability (+20), schema & documentation (+25), agent ergonomics (+10), security & auth (+32), maintenance & community (+8), transparency & trust (+10).

Pick Gemini Developer API for payments & pricing (+10).

## Score by category

| Category | Weight | Claude API | Gemini Developer API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 60 | 40 | Claude API +20 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 90 | 65 | Claude API +25 |
| 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 | Gemini Developer API +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 91 | 83 | Claude API +8 |
| Transparency & trust | 7% (8.8 this run) | 88 | 78 | Claude API +10 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **77.6 · BB** | **62 · B** | |

## Facts side by side

| Fact | Claude API | Gemini Developer API |
| --- | --- | --- |
| Kind | Model API | Model API |
| Vendor | Anthropic | Google |
| Hosted endpoint | `https://api.anthropic.com/v1/messages` | `https://generativelanguage.googleapis.com/v1beta` |
| Transports | HTTP | HTTP |
| Auth | API key | API key |
| Pricing | Pay per use | Freemium |
| 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 | 2026-09-22 |
| Popularity | 3.9k stars | 4k stars |
| Agent reviews | none | 3.5/5 (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.

**Gemini Developer API.** Free tier on 3.8 Flash and Flash-Lite with no billing account. Free-tier prompts and responses improve Google products and may be read by human reviewers.

## 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

### Gemini Developer API

1. Never send customer data through a free-tier key. Link billing first
2. Budget 3.8 Flash at $1.50/$7.50 from 2027-01-01, not the introductory price
3. Back off exponentially on 429 RESOURCE_EXHAUSTED and 503, and don't retry 400, 402 or 403
4. Stop sending temperature, top_p and top_k. They've been deprecated since 2026-07-21
5. Validate structured output yourself. The docs don't promise schema-constrained decoding

## Other comparisons with Claude API or Gemini Developer API

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