What you are observing
Batchlark is the retained concurrency study formerly called Queue Lab/Hermes. It is not a differentiated service; a practical science-oriented replacement is being evaluated. Its dashboard represents simulated 50 ms work, not real email, webhook or language-model deliveries. It retains state in memory and resets on restart.
Run it locally
Follow the tested source setup in the implementation notes . The served application uses Go and opens a dashboard on port 8080 by default. No API key or database is needed.
Submit a small batch and watch progress, bounded workers and server-sent events. Atomic admission rejects a batch that cannot fit rather than silently accepting part of it. Slow event readers are disconnected and can recover progress through polling.
Read the API and boundaries
The implementation reference lists dispatch, batch status, metrics, event stream and health endpoints, together with the race-test/vet/build commands. Production delivery would additionally need durable jobs, authentication, safe destinations, retries and idempotency. Those features and a separately hosted production backend are not claimed by the portfolio illustration.