When to use this. Reach for External API when the model is served somewhere else behind an
OpenAI-compatible API. If the model is on BenchGen use On a platform
model; to pull one from the Hub use From a HuggingFace
model.
Prerequisites
- A benchmark or environment to evaluate against, from the Environments Hub or a custom environment you uploaded.
- An OpenAI-compatible endpoint URL (for example
https://openrouter.ai/api/v1/chat/completions). - The model name as the provider expects it (for example
mistralai/mistral-small-24b-instruct-2501). - An API key or token, if the endpoint requires one.
Steps
1. Open a benchmark
Open the environment you want to evaluate against. The Overview tab describes what the benchmark measures and how it scores submissions.
2. Switch to the External API source
On the Evaluate tab, the model sources are grouped into tabs: Platform Models, Running, Trained, HuggingFace, and External API. Click External API.
3. Enter the endpoint details
Fill in the endpoint form:
4. Set run values (optional)
Expand Advanced: model environment & parameters to review what the benchmark injects. Model connection values are filled from the endpoint you entered; you fill only the fields the benchmark owner exposed (hereTOX_SYSTEM_PROMPT, TOX_MAX_QUESTIONS, and the optional TOX_JUDGE_* keys),
and you can adjust the sampling parameters.

5. Run the evaluation
Click Run Evaluation. BenchGen creates the run and opens a live view. While the endpoint is being wired up, the status reads Deploying and the logs wait for output.
MODEL_API_URL, MODEL_NAME, and the benchmark’s prefixed keys such as TOX_API_URL and
TOX_MODEL_NAME, followed by per-item progress like [ADIM] 1/30.

6. Review the results
When the run finishes, the status turns Completed and the Score Breakdown appears. The example below scored 96.7% (29 of 30 correct).
Next steps
- Read results: interpret the score breakdown and detailed table.
- Environment variables: how run values reach the model.
- On a platform model: benchmark a model already on BenchGen.