Transparency & Accountability
Trust Center
This page explains what CardOptimizer does, how it works, where our data comes from, and how we handle accuracy, independence, and monetization.
What This Tool Does
CardOptimizer is a rule-based eligibility checker for U.S. credit cards. It evaluates whether you are likely to be approved for a card and whether you qualify for its welcome bonus, based on publicly documented issuer policies.
What it does
- -Checks your profile against 21 issuer-specific eligibility rules
- -Identifies which cards you are likely blocked from and why
- -Shows when you may become eligible again, with estimated dates
- -Runs eligibility analysis entirely in your browser; optional account sync stores your profile securely in the cloud
What it does not do
- -Guarantee approval or denial of any card
- -Provide financial, investment, or credit advice
- -Access your credit report, credit score, or bank accounts
- -Submit applications or perform hard inquiries on your behalf
Methodology
CardOptimizer uses a deterministic rule engine. When you enter your credit card history, each card in our database is evaluated against the issuer-specific rules that apply to it. The engine returns one of four statuses:
The engine evaluates all applicable rules for each card and returns the most restrictive status. Every result links to a plain-language explanation of the rule that triggered it. The full list of rules is documented on our How It Works page.
Why We Test Every Rule
Issuer rules interact in non-obvious ways — Chase's 5/24 counts cards from all issuers, Marriott restrictions span both Chase and Amex, and Sapphire products share a 48-month bonus clock while also enforcing a one-card rule. Manual spot-checking doesn't scale when a single change can silently alter results for dozens of cards.
Date boundary testing
Rules like “48 months since last bonus” behave differently depending on evaluation date. Scenarios use fixed dates so the same test produces the same result regardless of when it runs.
Edge case regression
Real users have product-changed cards, authorized user accounts, and bonus histories with missing dates. Each edge case is captured as a permanent scenario — once a bug is fixed, it stays fixed.
Cross-rule interaction
When rules share data like bonus history or wallet status, a change in one rule's logic can break another. Verification across all scenarios catches these ripple effects.
Unintended rule drift
Small changes accumulate over time — a refactored utility, an updated calculation, a new data field. Continuous verification ensures behavior remains stable across updates.
Our Commitment
- Consistency: The same profile and card always produces the same result.
- Transparency: Every rule is documented with its source, logic, and limitations.
- Regression protection: No rule change ships without passing all existing scenarios.
- Honest uncertainty: When we don't have enough data, we say so — we never guess.
Data Sources
Our card database and eligibility rules are compiled from the following types of sources:
Official issuer terms and conditions
Card offers, annual fees, bonus terms, and product restrictions are sourced directly from issuer websites including Chase, American Express, Citi, Capital One, and others.
Publicly documented issuer policies
Rules such as Chase 5/24 and Amex lifetime language are derived from official terms, regulatory filings, and widely cited policy documentation.
Community-reported data points
Some rules (such as Citi velocity limits) are based on patterns observed across thousands of user-reported application outcomes from sources including Doctor of Credit and Reddit r/churning. These are clearly identified as observed rather than officially confirmed.
Update Policy
Card data and eligibility rules are maintained on the following schedule:
- -Card offers: Reviewed weekly. Welcome bonuses, annual fees, and offer expiration dates are checked against official issuer pages.
- -Eligibility rules: Reviewed monthly. Rule parameters are verified against current issuer terms and community data sources.
- -Breaking policy changes: Updated within 48 hours when a major issuer publicly changes a rule that affects eligibility outcomes.
The database currently tracks 131 active cards across 21 eligibility rules.
Error Correction
If you identify incorrect card data, an outdated rule, or an eligibility result that does not match a known issuer policy, we encourage you to report it. Accuracy is the foundation of this tool.
- -GitHub: Open a data issue with the card name, the expected behavior, and any supporting documentation.
- -Email: Contact [email protected] for issues not suited for a public tracker.
Confirmed errors are typically corrected within 1-3 business days.
Independence
CardOptimizer is an independent project built and maintained by Isaac Baek, a software engineer based in San Jose, California.
This tool is not affiliated with, endorsed by, or sponsored by any credit card issuer, bank, financial institution, or card network. The names and trademarks of card issuers and products are used solely for identification and informational purposes.
Eligibility results are generated entirely by deterministic rule logic. No issuer has any influence over which cards are shown, how they are ranked, or what eligibility status is returned.
Transparency
CardOptimizer does not currently earn revenue from card issuers or affiliate links. All application links point directly to official issuer pages. The eligibility engine operates independently of any commercial relationship.
If monetization is introduced in the future, it will be fully disclosed here and will not influence eligibility results or recommendation logic.
Important Disclaimer
CardOptimizer is an educational tool that provides rule-based eligibility analysis. It does not constitute financial advice, credit counseling, or a recommendation to apply for or avoid any financial product.
Eligibility results are estimates based on publicly documented issuer policies and community-reported data points. They do not account for factors such as credit score, income, debt-to-income ratio, or other underwriting criteria that issuers evaluate during the application process. A result of “eligible” does not guarantee approval. A result of “ineligible” does not guarantee denial.
You are solely responsible for any credit card application decisions. We recommend consulting a qualified financial advisor before making significant credit decisions.