MoneyKit is a fintech API — the kind of infrastructure that connects consumer bank accounts to the apps that need them, similar in spirit to Plaid. Their bug bounty pays $1,000 to $5,000. Look at that range again: the minimum is a thousand dollars. That floor alone makes this one of the most interesting direct programs on the independent circuit.
Program Overview
| Detail | Value |
|---|---|
| Reward range | $1,000 – $5,000 |
| Policy | moneykit.com/bounty |
| Submission | Email: security@moneykit.com |
| Type | Direct company program |
A high floor usually means one thing: the company only pays for findings that matter, and the policy will say so. Fintech companies are also more likely to run background checks on researchers and require identity verification for payouts. Read the bounty page completely before you begin.
Attack Surface: Where a Fintech API Breaks
Financial data APIs concentrate enormous value in narrow surfaces. The valuable bug classes are well understood:
- Link flows and consent. Bank-account linking is the product. If the consent flow can be manipulated — linking without proper authorization, retaining access after revocation, or a confusing state where a “revoked” connection still returns data — that’s a critical privacy incident.
- Token lifecycle. Access tokens, refresh logic, and scope enforcement. The highest-value question in any fintech API: does a token scoped to institution A ever return data from institution B? Token-scope confusion is the IDOR of the API world.
- Sandbox vs. production separation. Fintech APIs almost always ship a sandbox. Verify the boundary in both directions: sandbox credentials that produce production data, or production state that bleeds into test environments, are severe.
- Webhooks and callbacks. MoneyKit notifies client apps of account events. Webhook signature verification flaws, SSRF in callback registration, or replayable events are realistic and well-paid.
- Developer portal and dashboard. API key management, team roles, and account settings. Missing authorization checks on org-level operations (inviting users, rotating keys) map directly to the top of the severity ladder.
Beginner Mistakes to Avoid
1. Touching real bank data. Everything should happen in sandbox accounts you own. If you somehow encounter real consumer financial data — stop, note the conditions, and report immediately without downloading or exfiltrating anything. How you handle that moment defines whether you’re a researcher or a criminal in the eyes of both the company and the law.
2. Fake transaction testing against production. Simulating transfers, pushing test transactions into live rails, or probing payment flows in production is destructive testing at a fintech. Sandbox only.
3. Assuming the high floor means easy money. A $1,000 minimum usually means strict triage. Low-impact findings — headers, cookies, verbose errors — will be declined outright rather than paid a courtesy amount. Aim for auth logic or data isolation or don’t submit.
4. Skipping the identity/payout requirements. Direct fintech programs often require KYC-style verification to pay rewards. Know the process before reporting so a paperwork surprise doesn’t sour an accepted finding.
5. Testing at API-scanner speed. Rate-limited, low-and-slow, manual. Fintech backends monitor for exactly the traffic patterns automated tools produce.
Why Fintech APIs Pay the Best
The severity economics are simple: a bug in a photo-sharing app leaks photos; a bug in a bank-linking API leaks account numbers, balances, and transaction histories — and triggers regulatory exposure. Companies in regulated industries price that risk into their bounties. The same IDOR that pays $300 at a SaaS tool pays $5,000 here. If you’re willing to read API documentation carefully (an underrated skill), fintech is the highest-value corner of Web2 hunting.
Next Step
MoneyKit is one of 51 verified targets in the Web2 Bug Bounty Targets Database, with reward range, contact, and policy link in CSV/JSON — filter by payout floor and start where the money actually is.