Why a Deployment Checklist Matters for LLMs
Deploying an LLM to production is categorically different from deploying a traditional API. The model is a probabilistic system that can fail in non-deterministic ways: it may refuse valid requests, hallucinate factual information, generate unsafe content, or regress in quality after a seemingly unrelated infrastructure change. A structured checklist catches the gaps that exploratory development misses.
The 40 items in this checklist represent patterns from teams shipping production LLM applications. The phases follow the natural workflow: deciding what to build, fine-tuning if needed, validating quality rigorously, standing up infrastructure, monitoring in production, and ensuring legal and compliance requirements are met.
Phase 1: Model Selection
The model selection phase is often the most consequential and the most under-researched. Teams frequently default to the largest available model without measuring whether a smaller model is sufficient for their task, and without calculating whether the cost is sustainable at projected scale.
The key questions are: What quality level does your task actually require? Does the task need the reasoning depth of Claude Opus or GPT-4o, or is a cheaper model (Haiku, GPT-4o-mini, Gemini Flash) adequate? Can the model handle your expected context length? Does it support structured output formats your application requires (JSON mode, function calling, etc.)? Use our LLM comparison tool to evaluate these dimensions side by side.
Phase 2: Fine-Tuning
Fine-tuning is optional but can unlock significant gains in format consistency, domain accuracy, and inference cost efficiency. The decision to fine-tune should be based on concrete evidence — a baseline evaluation showing that prompt engineering alone is insufficient — rather than assumption.
If you do fine-tune, data quality is the primary determinant of outcome. 500 carefully curated examples outperform 5,000 mediocre ones. Each training example should represent the exact input/output behavior you want the model to exhibit, including edge cases and refusals. Use our fine-tuning cost calculator to estimate training cost and break-even before committing.
Phase 3: Evaluation
Evaluation is where most LLM deployments are weakest. "Looked good in testing" is not sufficient. A proper evaluation harness includes: a held-out test set with ground truth answers, automated metrics (ROUGE, BLEU, semantic similarity, or task-specific scoring), human rating for subjective quality, adversarial test cases targeting known failure modes, and regression tests that run on every deployment.
For safety-critical applications, red-teaming — systematically attempting to elicit harmful or incorrect outputs — should be documented before launch. Track evaluation results across model versions so regressions are immediately visible.
Phase 4: Infrastructure
Infrastructure for LLM applications has unique requirements. Latency is typically 1–30 seconds per request (vs milliseconds for traditional APIs), requiring timeout handling, streaming support, and user-facing loading states. Rate limits must be managed both at the provider level (per-minute and per-day caps) and at the application level (per-user quotas to prevent runaway costs). Retry logic with exponential backoff is essential for the 429 and 503 errors that occur under load.
Prompt and response logging requires careful design. Logs are essential for debugging and evaluation, but may contain sensitive user data. Decide on a data retention and access policy before launch, not after an incident.
Phase 5: Monitoring
Production LLM systems degrade in ways that are invisible without active monitoring. Model providers update underlying models (sometimes without notice), prompt caching behavior changes, latency profiles shift, and user behavior evolves in ways that surface new edge cases. Monitoring should track: response latency (p50, p95, p99), error rates by error type, token consumption and cost per day, output quality via automated scoring, and user-reported feedback signals.
Set alerting thresholds before launch. A latency spike or cost anomaly discovered the next morning in a dashboard is much worse than one that triggers an alert at 3am.
Phase 6: Compliance
Compliance requirements for LLM applications vary by use case and jurisdiction. Consumer-facing applications have stricter obligations than internal tools. Applications handling medical, legal, or financial information face additional regulatory scrutiny. The minimum requirements for most applications include: a reviewed terms of service covering AI-generated content, a data handling policy covering what user inputs are stored and for how long, compliance with provider usage policies (each provider has restrictions on use cases), and content filtering to prevent generation of illegal or harmful material.
Many teams defer compliance to "later" and find themselves unable to launch or forced into expensive retroactive changes. Completing the compliance phase before launch avoids both scenarios.