Routing Between Local Gemma 4 and the Gemini API Cut My Bill from ¥32,000 to ¥9,000 — A Production Hybrid Router Design
How I cut a ¥32,000/month Gemini API bill to the ¥9,000 range with hybrid inference: routing design, a full Python router, production pitfalls, and how Gemma 4 arriving on the Gemini API in July 2026 changes the decision.
Guarding Gemini API Responses in CI: Snapshot and Semantic Regression Testing
How to defend non-deterministic Gemini API responses with pytest snapshot tests plus embedding-based semantic regression detection — including CI wiring, separating flakiness from real regressions, and snapshot-update governance, all in working code.
Mixing Text and Images in One File Search Skewed My Results Toward Images — Rebalancing by Modality After Retrieval
When you put text and images in a single File Search store with gemini-embedding-2, results can quietly skew toward one modality. Here is how to measure that skew and even it out after retrieval, using per-modality normalization and quota-based merging — with working code.
A Promotion Gate So gemini-flash-latest Flipping to 3.5 Flash Doesn't Break Your Pipeline at 3 AM
Floating aliases like gemini-flash-latest swap their target on every GA, quietly shifting the assumptions your unattended automation depends on. Here is a role-to-pinned-ID indirection layer, an acceptance harness that measures four metrics against your own golden set, and threshold-driven promotion and automatic rollback — with working code.
Turning Articles into Audio with the Gemini 3.1 Flash TTS Preview: Splitting Long Text, Stitching It Back, and What It Actually Costs
The Gemini 3.1 Flash TTS preview launched today. Here is a single-narrator pipeline that converts a written article into clean audio, including how to split long text, stitch PCM without ugly seams, keep one voice steady, and estimate the real per-article cost.
The Morning a Preview Image Model Went Dark — Migrating to GA Gemini Image Models and Building a Deprecation-Resilient Pipeline
With gemini-3.1-flash-image-preview and gemini-3-pro-image-preview retired, here is how to migrate to the GA models and design an image pipeline that no longer gets caught off guard by deprecation dates — with code and cost math, plus video-to-image thumbnail automation.
Structured Product Image Analysis with the Gemini API — A Production Pipeline Built on Thousands of Photos
Turn a one-off image analysis script into a production pipeline that auto-generates tags, descriptions, and categories at scale — covering structured output, resumable batches, measured cost, and model routing learned from real indie-developer operation.
Gemini API Implicit Caching Not Working — Troubleshooting Guide by Root Cause
Troubleshoot Gemini API implicit caching issues: cache not hitting, unexpectedly high costs, or low cache hit rates. Covers token thresholds, prompt structure, model version consistency, TTL expiry, and multimodal caching with code examples.
When Gemini's Maps Grounding Quietly Fails in Production — Field Notes on Attribution, Billing Boundaries, and Fallbacks
An operations-focused look at the pitfalls that surface after you ship Grounding with Google Maps on Gemini: detecting silent grounding misses, meeting the attribution requirement, knowing which responses are billed, and building fallbacks for latency and staleness.
Track Gemini API Costs in Production with usageMetadata — A Per-Request Logging Pattern That Reconciles With Your Bill
A production pattern for capturing Gemini API's usageMetadata per request to attribute spend by endpoint, user, and model — hardened for the 3.5 Flash GA era where the default model can shift under you. Covers pricing keyed on resp.model_version and a nightly audit that flags model drift and unknown models before the invoice does.
Moving My Automation Off the Gemini CLI Before the June 18 Shutdown
On June 18, the Gemini CLI stops responding for hosted plans. Here is how I moved unattended scripts that called gemini from the shell over to the google-genai SDK, with structured output, retries, and cost measurement built in.
Defending Against Prompt Injection When You Pass External Text to the Gemini API
User reviews, scraped articles, and other untrusted text are the entry point for indirect prompt injection when you feed them to the Gemini API. Here is a prioritized, code-backed defense you can drop into a production pipeline: trust-boundary isolation, schema constraints, a two-stage screening pass, and output sanitization.