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Folio

Methodology

How a sentence in a bank's terms becomes a number on this site, and what we do when we are unsure.

From document to number

Every figure passes through four stages: evidence (an archived copy of an official document, with a content hash and retrieval time), structured rules (earn rates, caps, exclusions, milestones, fees and benefits in a validated format), a deterministic calculation engine, and an explanation that links each result to the rule and evidence behind it. Language models may help read a document, but they never compute a value: every number comes from tested code using decimal arithmetic.

Source hierarchy

When official sources disagree, Folio records the conflict and keeps the affected value unpublished or unchanged until new evidence resolves it. It does not silently choose a value. The case stays in automatic research and does not require a person to keep the system running.

  1. Most important terms and conditions (MITC)
  2. Terms And Conditions
  3. Fee Schedule
  4. Rewards Document
  5. Product Page
  6. Network Document
  7. Partner Document
  8. Issuer Communication
  9. Secondary Source
  10. Community Report

Versions and history

Card terms are stored as versions with an effective date range. A new version never overwrites an old one: you can view any card as of any date, and every change between versions is recorded rule by rule with its announcement, effective and discovery dates. Archived documents and extracted evidence are append-only; human corrections are stored alongside the original extraction, never in place of it.

How values are calculated

Your monthly spending is expanded into individual transactions using typical ticket sizes. Each transaction is matched to reward rules (merchant, category, channel, amount limits), points are rounded the way the issuer rounds them, and caps are applied per statement cycle, month, quarter or year in the order spending happens. Milestones, fee waivers, surcharges, forex markup and GST are then applied.

Points are valued in bands:

Benefits

Benefits have a theoretical value (every entitlement used) and a realisable value (only what you said you would use). Unless you change them, we assume a domestic lounge visit is worth ₹1,000, an international visit ₹2,500, a movie ticket ₹300, and that vouchers realise 90% of face value. Insurance cover and concierge services are listed but not valued.

Confidence

Separately, each card shows when its sources were last checked. A source that has not been rechecked recently is marked stale.

Checking status

Each real card also carries a checking status, computed by code from what has actually been checked, so it cannot be set by hand:

Monitoring re-reads the specific sentences bound to rules on already modeled cards. When one of those sentences changes, the new value becomes a proposal with its measured yearly effect on standard spending profiles. A sentence that disappears is held for new evidence, never guessed. The card directories of monitored issuers are scanned daily for new cards, removed cards and new documents.

What Folio does on its own

Folio operates autonomously and handles cases automatically only when a fixed list of checks passes (for example: the page is on the issuer's own domain, an unchangeable copy was archived, the name agrees with its own address, no document disagrees, the effective date is stated). Cases that fail a gate stay unpublished and return to research when new evidence is available; they do not require a person to keep the system running. There is no confidence score an AI could raise to publish something. Each automatic action records which checks ran, which passed, the evidence and the policy version that allowed it, and an administrator can reverse it without erasing the history.

Automatic publication and human verification are separate: a card added or updated automatically is never described as verified.

Every card page can explain a single purchase step by step (the rule that matched, exclusions and caps already used). The same trace is available as JSON at /api/cards/<card>/trace?category=ONLINE&amount=5000.

Sample data and real cards

Development and test environments use fictional demonstration cards to exercise calculations and history. They are excluded from Folio's public directory, comparisons, calculations, change feed and issuer pages.

Real card identities are added automatically from issuer directories. Product-page research can publish a partial first version when it finds an unambiguous joining, annual or renewal fee. It can also model an explicit cashback rate only when the issuer says it applies to all eligible spend, purchases, or transactions, or a points-per-rupee rate explicitly identified as the base earn. Category-specific rewards and other unsupported fields remain unknown until a deterministic parser can map their terms exactly. Unknown exclusions, point values, or caps keep calculator results indeterminate; unknown values are never treated as zero. Cards without a published version stay outside calculations and comparisons, and automatic publication never marks a card as human-verified.

Privacy

Your spending profile is saved only in your browser. It is sent with each calculation request, used in memory, and never stored or logged on the server.

Not financial advice

Figures are estimates based on published terms and stated assumptions. Issuers change terms, sometimes without notice. Check the issuer's current terms before applying. See recent changes.