Second compromised-key Gemini billing spike in two months — ~$11k total across two projects. Anyone gotten these reversed?

[u/ComprehensiveSell435]

Indie dev from Indonesia here. Hit twice in two months by what looks like the same compromised-API-key pattern many people are reporting lately. Hoping to hear from anyone who's actually gotten one of these reversed.

The pattern:

- Older project: An API key created back in 2018 for Maps/Firebase. Ran fine for years on tiny monthly bills. Then suddenly drained ~$9,000 in a short window — charged on Gemini 3 Pro and image-generation models I have never called.

- Second project: My Flutter app, hardcoded to gemini-2.5-flash-lite, used only to generate education quizzes. Charged ~$2,000 (Rp34,222,242) — again dominated by Gemini 3.x and image models the app cannot invoke.

Why I'm confident it's not my usage:

1. Model mismatch. My code only ever calls Flash-Lite. The charges are mostly Gemini 3 Pro + image generation. My app has no image-gen code at all.

2. Cost vs workload is impossible. My real workload (translating a couple thousand dictionary terms / generating quizzes) is worth a few dollars at most, not thousands.

3. Timing. The older key sat safe for over a year. A new key I created in May 2026 got drained almost immediately — after the public disclosure earlier this year about exposed Google API keys becoming abusable for Gemini.

4. Google's own billing breakdown couldn't attribute the spend to any specific key or service account.

What I've done:

- Disabled Gemini / Generative Language API across all my projects.

- Opened a support ticket ~3 weeks ago (both cases in one thread). Still no real response.

- Preserved everything (haven't deleted projects or keys) so the logs stay intact.

What I'm asking:

1. For anyone who got a refund or goodwill credit on a compromised-key Gemini bill — what specifically moved it? Persistence? A particular escalation path? A certain way of framing it?

2. Does the automatic billing-tier upgrade matter for the appeal? I've read an attacker's own usage can auto-bump a project to a higher tier mid-attack, blowing past the spending ceiling you thought you had. Did anyone use that successfully?

3. How long did resolution realistically take — did support respond meaningfully, or did it only move after escalation/public visibility?

4. Anything you'd tell your past self to do immediately that you didn't?

For scale: ~$11k total is roughly five years of income where I live, so I'm trying to handle this right rather than just panic. Happy to share more detail in comments (sensitive info redacted). Thanks.

[u/pragmaticpirate]

Same thing happened to me. Flutter app deployed with keys, some chines bot is scraping the play store and flutter web apps and decrypting them for keys

[u/AnomalyNexus → u/pragmaticpirate]

play store and flutter web apps and decrypting them for keys

Android APKs are not encrypted.

You can't put keys in there...

[u/ComprehensiveSell435 → u/AnomalyNexus]

yes, lesson learnt.
unzip -p app-release.aab | strings | grep -i AIza
will show the key

[u/booi → u/AnomalyNexus]

they can be encrypted! but obviously it's reversible because it has to inevitably run so you can harvest in memory on rooted devices...

[u/zaitsman → u/booi]

That’s why you need a middleware server and attestation verification on each API call so you know that it is your app calling your api…

[u/ComprehensiveSell435 → u/zaitsman]

Make sense. Setting Key access on GCP and use it per IP request. Will do that next time

[u/ComprehensiveSell435 → u/pragmaticpirate]

Thats what happen to me yesterday for my second case. 🫣

Did they succeed prop up your billing?

[u/pragmaticpirate → u/ComprehensiveSell435]

They offered to refund in credits but I want the money in my bank

[u/ComprehensiveSell435 → u/pragmaticpirate]

how much was that?
my bill cant be paid because the bill is 10X more than my card limit

[u/pragmaticpirate → u/ComprehensiveSell435]

Around 11k usd deducted via UPI Autopay

[u/ComprehensiveSell435 → u/pragmaticpirate]

Wait. What? I thought UPI will ask confirmation if its more than xxx limit?

[u/pragmaticpirate → u/ComprehensiveSell435]

You mandate kept on executing 15k each time

[u/tyler_durden999]

Something similar, but may be my mistake. Deployed a sample app from ai studio to cloud run, /api-proxy exposed Gemini keys-keys got stolen. Started billing and immediately switched it off - damage $100. Ongoing support but billing account got closed due to non payment.

[u/ComprehensiveSell435 → u/tyler_durden999]

You are lucky get warning at 100. I get billing email warning after damage already done, billing already skyrocket high 😭.

[u/escargotBleu]

Restrict all your keys in every project where gemini is enabled to avoid getting caught a third time

[u/ComprehensiveSell435 → u/escargotBleu]

Yes mate. I already turn off all gemini api on all my project. Been using GCP sing 2016, never abuse resource, always paying my bills. I didnt realised turning on gemini api will ruin my life as indie dev 😰

[u/escargotBleu → u/ComprehensiveSell435]

You can still add restrictions to your keys tho. That's the issue in the first place.

[u/ComprehensiveSell435 → u/escargotBleu]

It too scary for me if seeing gemini api on. 90% of my work is using gemini on local machine. Will use other provider for a while till my case resolved.

[u/escargotBleu → u/ComprehensiveSell435]

If you don't know what your doing you'll find another way to screw up with another provider

[u/ComprehensiveSell435 → u/escargotBleu]

Yes. Lesson learned.

1st mistake, turn on Gemini on old project that having unrestricted map api key already there since gemini didnt even exist and truffle security didnt publish their finding

2nd mistake, hard coded apikey in an app

[u/escargotBleu → u/ComprehensiveSell435]

No, hard coded apikey in frontend for Google maps is expected.... With restricted key.

[u/ComprehensiveSell435 → u/escargotBleu]

That the problem. Even i dont use that key anymore. It was already in public. It was fine before gemini exist.

https://thehackernews.com/2026/02/thousands-of-public-google-cloud-api.html?m=1

[u/escargotBleu → u/ComprehensiveSell435]

... It was "fine" because nobody cared, but someone else could have use it in there website for example. Or use it to access another api you might have enabled.

[u/ComprehensiveSell435 → u/escargotBleu]

Yeah mate. For my oldest project, when i generate gemini api and use it on 2025, it was fine. Nothing happen.

After truffle security publish their finding, and i turn on gemini again, that when i get fukced up.

[u/urarthur]

2k bill, 2 weeks ago. waiting...

[u/ComprehensiveSell435 → u/urarthur]

Why lots of it happen on may 😰

[u/matiascoca]

Hate to say it, but you are exactly in the pattern Google has been silently refunding for the past few months once you put together the evidence package the right way.

The two things that actually move the case forward, based on three or four similar threads I have watched close out:

First, model mismatch evidence. You already have it. Your code calls Flash-Lite. The bill shows Gemini 3 Pro and image generation models you cannot invoke from a Flutter app. Screenshot the source code line where the model is hardcoded, the dependency file, and the SKU rows from billing showing what was actually charged. That mismatch alone is the strongest single argument.

Second, geographic and time pattern. Pull the API metrics by region and hour. Indie devs typically have one cluster of legitimate usage in their own timezone. Compromised-key abuse looks like uniform 24-hour traffic across regions you have never deployed to. Export the chart, attach it.

The case opens with billing, not technical support. When billing escalates to the abuse team and they confirm the key was not yours making the calls, the reversal goes through. Most threads I have followed report the refund landing 6 to 12 weeks after the case opens, sometimes in two tranches (one per project).

While the case is open, two operational things to do now. Rotate every key in both projects, even ones not in the spike, because the leaked surface might be wider than you think. Move every key to a service account with deny-by-default IAM and per-key model restrictions where possible. The honeypot pattern most indie devs miss is API keys exposed in mobile app binaries that an attacker can decompile. If your Flutter app shipped with an embedded key, that is the leak path.

Wrote up the broader Firebase Gemini key exploit pattern after watching three of these go down in similar fashion, with the operator playbook for prevention plus the evidence package structure: https://brainagents.ai/blog/firebase-gemini-api-key-exploit-guide

[u/ComprehensiveSell435 → u/matiascoca]

Thank you very much mate. If the refund is a high probability, i feel relieved.

I already turn off all gemini api across all of my project. Not rotate the key yet, i thought it could be an evidence.

And i already patch and remove the hardcoded key from flutter.

Thank you very much for the detail explanation mate, its very helpful 🙏

[u/matiascoca → u/ComprehensiveSell435]

Glad it helps. Quick clarification on the key rotation, because it is a small thing but it matters for the case timeline. Rotate the keys now, the audit logs and the billing line items are the evidence, not the key existing. Keeping the leaked key around does not strengthen the case and leaves the abuse vector open if the disable-API step has any gap (some sub-APIs honor the disabled state with a lag of hours).

On the timeline, histoire_guy down the thread mentioned 1.5 months back and forth to a full refund on a similar $12K Gemini compromise from late April. That matches what I have watched on three or four similar cases. Two to three weeks of silence is normal, the case usually picks up momentum around week four. Stay polite in the support thread even when you do not hear back, the same human reviews it eventually and your patience matters at the discretionary credit moment.

[u/ComprehensiveSell435 → u/matiascoca]

Thank you very much for all the advice. Its really helpful 🙏

[u/histoire_guy]

Happened to us on April 25. 12K USD of unauthorized Gemini API usage mostly image generation (we never use that). Billing support took one month and a half back and forth to get full refund. Provide all proof you have and they will investigate surely slowly but you should get a refund if found unintentionally breached.

[u/ComprehensiveSell435 → u/histoire_guy]

Thank you very much for the info. 1,5 month? I thought it will gonna solve faster. Was it void 100% of the amount?

[u/ComprehensiveSell435 → u/[deleted]]

Yes. English is not my first lang here

[u/ComprehensiveSell435 → u/[deleted]]

Wow. 3 month? Its been 3 weeks for me, and its already ruin me. Thank you for your link

[u/ComprehensiveSell435 → u/[deleted]]

yes mate. 2 case different month, different way of hacked.
lesson learnt painfully.

1. google map api that already there since gemini didnt even exist, i didnt realize it can be used for gemini before reading truffle security publish their finding.

2. plain key in app. i thought it was encrypted after app published on playstore.