Deterministic Grammar Decoding & Schema Lab

Enterprise Structured Output & JSON Grammar Decoding Simulator

Simulate and benchmark deterministic constrained decoding (Outlines, vLLM XGrammar, GBNF) vs unconstrained prompt generation and Pydantic retry loops. Calculate sub-5ms vocabulary logit masking, zero retry token wastage, and cloud cost arbitrage.

Grammar Decoding Architecture Comparison

Elesium Constrained Decoding (XGrammar / Outlines)

GPU-accelerated context-free grammar masks invalid token logits in sub-5μs per token, guaranteeing 0.0% JSON parse exceptions and zero retry token wastage.

Syntax Failures: 0.0% | Retries: 0 | Latency: 380ms

Cloud Vendor Function Calling API

Server-side proprietary masking provides schema enforcement but charges steep cloud token rates ($10/1M output) with +95ms masking TTFT overhead.

Syntax Failures: 1.2% | Latency: 515ms | Premium Pricing

Unconstrained Prompt + Pydantic Retries

Missing quotes and trailing commas cause frequent syntax exceptions (8%–18%), triggering costly re-prompts that multiply latency and token consumption.

Syntax Failures: 8.6% | Latency: 720ms | Wasted Tokens: 1.4x