Measuring the Economics of Each Gemini-Powered Feature — So You Can Keep It, Fix It, or Retire It
Gemini API costs are visible at the account level, but the profitability of an individual feature never shows up on its own. This guide shows how to tag every request, build a per-feature cost ledger, join it with revenue signals from AdMob and in-app purchases to compute contribution margin, and decide whether to keep, fix, or retire each feature — with the code I actually run.
Why Gemini API Throws 'Unsupported MIME type' and How to Fix It
The 'Unsupported MIME type' error from the Gemini API has three distinct causes: a misspelled MIME string, an octet-stream upload, and a genuinely unsupported format. Here is how to tell them apart with code that actually works.
Why Gemini 2.5 Pro Rejects thinkingBudget: 0 (and How to Fix It)
Setting thinkingBudget to 0 on Gemini 2.5 Pro returns a 400 INVALID_ARGUMENT error. Here is why the per-model thinking budget ranges differ, how to minimize thinking on Pro the right way, and when to switch to Flash, with Python and JavaScript examples.
Two Months of Turning App Store Connect Daily Sales into a Slack Digest with Gemini 2.5 Flash
Notes from two months of running App Store Connect Sales/Trends data through Gemini 2.5 Flash and posting a short morning digest to Slack. Why Flash beat Pro for this job, how AdMob and store revenue stopped colliding, and what a single 'normal/check' label changed.
Propagating a Time Budget Through a Multi-Stage Gemini Pipeline
A field memo on killing DEADLINE_EXCEEDED errors in an in-app help search by carrying a single request-wide deadline through the embed, search, and generate stages — sizing maxOutputTokens from the remaining budget and reserving a fallback budget so a breach returns a partial answer instead of an error.
Why HTTP Referrer Restrictions on Your Gemini API Key Cause 403 Errors in Production
Walks through why a Gemini API key with HTTP referrer restrictions can suddenly return 403 PERMISSION_DENIED in production. Covers the exact referrer string format, SDK behavior differences, how to safely route around the limitation with a tiny edge proxy, and how it differs from the CORS error you hit when calling straight from the browser.
Layering Gemini API Response Caches in Three Tiers — How I Split Memory, Redis, and Context Cache
Notes from running a three-tier cache (in-memory, Redis, Gemini Context Cache) in front of the Gemini API for six weeks across a wallpaper app — actual hit rates, billing impact, and the invalidation traps that ate me alive.
Why per-turn generationConfig is ignored in Gemini API chat sessions
If you pass a different generationConfig (temperature, max_output_tokens, response_schema) to each send_message in a google-genai chat session and the behavior never changes, this walkthrough shows what is actually happening, why the SDK is designed that way, and three workarounds we use in production for review-summary and reply-draft pipelines.
Running an SLO and Error Budget for the Gemini API as an Indie Developer — Guarding Four Sites with Burn-Rate Monitoring
Notes from running the Gemini API inside four production sites as an indie developer. A practical SLO and Error Budget design that fits a single-person operation: Cloudflare Workers and KV for burn-rate calculation, simplified multi-window alerts, and decision rules for what to freeze when the budget runs out.
A Daily Slack Digest of Six Apps' Store Reviews, Built with Gemini Flash
How I built a Cloud Run + Gemini Flash ETL that translates, classifies, and prioritizes 30–80 daily store reviews across six apps and posts them to Slack — cutting my review triage from 60 minutes to 12, for about $4 a month.
Pairing Gemini API with Apple FoundationModels (iOS 26): An On-Device-First Hybrid Routing Notebook
Running iOS 26 FoundationModels alongside Gemini API as a hybrid stack for a wallpaper app's poem-from-image feature: routing decisions, full Swift code, and one week of latency and cost numbers.
Designing a Semantic Cache for the Gemini API — Embedding-based Answer Caching That Actually Pays for Itself
A practical design for a semantic cache that sits in front of the Gemini API. Combines text-embedding-004, cosine similarity thresholds, versioned cache keys, and TTL design to balance hit rate and answer quality, with Python and Cloudflare Vectorize code that runs in production.