https://generativelanguage.googleapis.com. Free-tier access is provided through Google AI Studio, while paid usage is billed through a Google Cloud project.
Monitor your current quota and usage in Google AI Studio or in the Google Cloud Console if you are using a Cloud billing account.
Supported models
Garth supports the following Gemini models for code review and scan requests.| Model | Best for | Context window |
|---|---|---|
gemini-2.0-flash | Recommended. Fast, accurate reviews with low latency | 1M tokens |
gemini-1.5-pro | Complex reasoning over very large diffs and full-repository context | 2M tokens |
gemini-1.5-flash | High-volume, lower-cost reviews where speed is the priority | 1M tokens |
gemini-1.5-flash-8b | Lightest model for simple, routine reviews | 1M tokens |
Usage tiers
The Gemini API provides a free tier for evaluation, and three paid tiers that unlock higher rate limits based on your billing history and cumulative spend.| Tier | Qualifications | Features |
|---|---|---|
| Free | Available to eligible countries; no credit card required | No charge. Requests may be used to improve Google products. Lower rate limits. |
| Tier 1 | Billing account linked to the project | Requests are not used for product improvement. Paid per token. Standard limits. |
| Tier 2 | Total spend of at least $250 + 30 days since successful payment | Higher rate limits for growing applications. |
| Tier 3 | Total spend of at least $1,000 + 30 days since successful payment | Maximum rate limits for enterprise-scale workloads. |
For production use, Garth requires at least Tier 1. This removes data usage restrictions and unlocks significantly higher rate limits for concurrent pull request reviews. New accounts must use prepaid billing and will be subject to a monthly spend cap.
Rate limits
Free tier
| Model | RPM | TPM | RPD |
|---|---|---|---|
gemini-2.0-flash | 15 | 1,000,000 | 1,500 |
gemini-1.5-pro | 2 | 32,000 | 50 |
gemini-1.5-flash | 15 | 1,000,000 | 1,500 |
gemini-1.5-flash-8b | 15 | 1,000,000 | 1,500 |
Tier 1 and above (Paid tiers)
Upon linking a billing account (Tier 1), rate limits increase substantially. Limits scale further as you reach Tiers 2 and 3. Representative Tier 1 limits:| Model | RPM | TPM | RPD |
|---|---|---|---|
gemini-2.0-flash | 2,000 | 4,000,000 | — |
gemini-1.5-pro | 1,000 | 4,000,000 | — |
gemini-1.5-flash | 2,000 | 4,000,000 | — |
gemini-1.5-flash-8b | 4,000 | 4,000,000 | — |
RPM = requests per minute · TPM = tokens per minute · RPD = requests per day. Paid tier limits can be further increased by requesting a quota increase in the Google Cloud Console.
Choosing the right tier for your team
Free tier — Evaluation only
Fewer than 5 developers trialling Gemini BYOK. The free tier’s low RPM and RPD caps make it unsuitable for sustained team use.
Tier 1 / Tier 2 — Small to medium teams
10–100 developers with regular PR activity. The 2,000 RPM limit on
gemini-2.0-flash handles dozens of concurrent reviews. Enable Cloud billing to unlock Tier 1.Tier 3 & Quota increases — Large engineering orgs
100+ developers or monorepos. If Tier 3 limits are insufficient, request a TPM or RPM increase through the Google Cloud Console quotas page.
Token consumption per review
Each Garth review consumes input tokens (your diff and context) and output tokens (the review comments). Estimates below are forgemini-2.0-flash.
| Review size | Typical input tokens | Typical output tokens |
|---|---|---|
| Small PR (1–5 files, < 200 lines) | 3,000 – 8,000 | 500 – 1,500 |
| Medium PR (5–20 files, 200–800 lines) | 8,000 – 25,000 | 1,500 – 4,000 |
| Large PR (20+ files, 800+ lines) | 25,000 – 80,000 | 4,000 – 10,000 |
Rate limit errors
If your account hits a rate limit, Garth retries automatically with exponential backoff. Sustained limits may delay when review comments are posted. What you will see:- A delayed review comment once the retry succeeds
- A dashboard notification if retries are exhausted and the review is dropped
- Enable Cloud billing to upgrade from the free tier to pay-as-you-go
- Request a quota increase in the Google Cloud Console
- Switch to
gemini-2.0-flashorgemini-1.5-flashto reduce per-request cost and increase throughput - Contact support if you need help sizing the right plan
Getting a Gemini API key
Sign in to Google AI Studio
Go to aistudio.google.com and sign in with your Google account.
Create an API key
Click Get API key in the left sidebar, then click Create API key. Choose an existing Google Cloud project or create a new one to associate the key with.
Enable Cloud billing (recommended)
To unlock pay-as-you-go rate limits, open the Google Cloud Console, select your project, and link a billing account. This upgrades your quota automatically.
Copy and store the key
Copy the generated key — it starts with
AIza. Paste it into Garth’s Settings → Integrations → LLM under the Gemini provider.Provider references
Official Google documentation for Gemini models, pricing, and rate limits.Gemini models
Full list of available Gemini models with context windows and capabilities.
Rate limits
Official rate limit reference for free and pay-as-you-go tiers.
Pricing
Per-token pricing for all Gemini models.
Google AI Studio — API keys
Create and manage your Gemini API keys in Google AI Studio.
Next steps
BYOK overview
Add your Gemini key to Garth’s secure vault and set it as your active provider.
Google AI Studio — API keys
Manage your Gemini API keys and view usage in Google AI Studio.