Gemini 3.1 Flash Lite Preview vs Grok Code Fast 1
In our testing Gemini 3.1 Flash Lite Preview is the better all-round choice — it wins 8 of 12 internal benchmarks driven by safety, faithfulness and structured output. Grok Code Fast 1 wins the agentic planning and classification tests and is slightly cheaper on input tokens, so pick Grok when you need a coding agent with visible reasoning traces and marginal cost savings.
Gemini 3.1 Flash Lite Preview
Benchmark Scores
External Benchmarks
Pricing
Input
$0.250/MTok
Output
$1.50/MTok
modelpicker.net
xai
Grok Code Fast 1
Benchmark Scores
External Benchmarks
Pricing
Input
$0.200/MTok
Output
$1.50/MTok
modelpicker.net
Benchmark Analysis
Across our 12-test suite Gemini 3.1 Flash Lite Preview wins 8 tests, Grok Code Fast 1 wins 2, and 2 tie. Test-by-test (our scores): structured_output 5 vs 4 (Gemini wins; Gemini is tied for 1st of 54 models on structured output), strategic_analysis 5 vs 3 (Gemini wins; tied for 1st of 54), constrained_rewriting 4 vs 3 (Gemini wins; rank 6 of 53), creative_problem_solving 4 vs 3 (Gemini wins; rank 9 of 54), faithfulness 5 vs 4 (Gemini wins; tied for 1st of 55), safety_calibration 5 vs 2 (Gemini wins emphatically; tied for 1st of 55), persona_consistency 5 vs 4 (Gemini wins; tied for 1st of 53), multilingual 5 vs 4 (Gemini wins; tied for 1st of 55). Grok wins classification 4 vs 3 (Grok tied for 1st of 53) and agentic_planning 5 vs 4 (Grok tied for 1st of 54), which aligns with its design as a fast, agentic coding model. Tool_calling and long_context tie at 4 vs 4 — both models handle function selection and 30K+ retrieval comparably in our tests. Practically: Gemini’s strengths (safety, faithfulness, structured output) matter for production systems that enforce content policy, produce strict JSON schemas, and summarize source material without hallucination. Grok’s wins (classification, agentic planning) matter for developer-facing coding agents and goal decomposition workflows; its visible reasoning traces (quirk: uses_reasoning_tokens) can help steer agentic runs.
Pricing Analysis
Both models charge $1.50 per mTok for output. Gemini charges $0.25/mTok input; Grok charges $0.20/mTok input. Using a 50/50 input:output token split (1 mTok = 1,000 tokens), monthly costs scale linearly: for 1M tokens (500 mTok input + 500 mTok output) Gemini ≈ $875/month vs Grok ≈ $850/month (difference $25). At 10M tokens Gemini ≈ $8,750 vs Grok ≈ $8,500 (difference $250). At 100M tokens Gemini ≈ $87,500 vs Grok ≈ $85,000 (difference $2,500). The gap grows with volume but output spending dominates both plans; teams doing very high-volume inference (tens of millions+ tokens/month) should account for the $0.05/mTok input premium on Gemini, while smaller-scale users will find the cost difference negligible relative to model capability.
Real-World Cost Comparison
Bottom Line
Choose Gemini 3.1 Flash Lite Preview if you need production-grade safety, strong faithfulness to source material, robust structured-output (JSON/schema) and multilingual/persona consistency at scale. Choose Grok Code Fast 1 if you need a lower-input-cost, developer-oriented coding agent that scores higher on agentic planning and classification, and you value visible reasoning traces for steering code workflows.
How We Test
We test every model against our 12-benchmark suite covering tool calling, agentic planning, creative problem solving, safety calibration, and more. Each test is scored 1–5 by an LLM judge. Read our full methodology.