Privacy-Preserving Eligibility Verification API
Confirm whether someone is eligible for access, tickets or benefits without dragging raw personal data through every service. AffixIO returns a binary decision and an optional token you can attach to your own flows.
Eligibility checks leak more data than they need
Many access and benefit flows collect far more personal data than the decision requires. This increases your compliance surface without improving the quality of your eligibility rules.
The result is duplicated PII in multiple systems, complex retention policies and higher risk when something goes wrong.
Checking benefit eligibility without oversharing
A program needs to know whether someone is eligible for a travel subsidy. The decision depends on income band and residency status, but your application only needs to know whether to apply the discount.
With AffixIO, the underlying data can be evaluated inside the verification layer. Your system receives a binary answer and an optional token to attach to the ticket or booking, without storing the raw income or address data.
From input to binary decision and token
1. Send only the inputs required for the decision
The API accepts identifiers or minimal attributes needed for the rule set, such as a hashed user ID, program ID, and context.
2. Evaluate rules and proofs inside AffixIO
AffixIO applies configured rules, checks proofs, and determines whether the conditions are met. Where possible, evaluation can be stateless and based on cryptographic proofs rather than stored records.
3. Return a yes/no decision plus optional token
The response contains a simple eligible flag, optional reason codes, and a short-lived token that can be attached to tickets, passes or sessions.
4. Verify tokens without re-exposing raw data
Other systems can verify the token with AffixIO to prove that an eligibility check was performed, without re-sending the original PII. This supports binary eligibility models described in Binary Eligibility Verification Without Storing Personal Data.
Input → verification logic → yes/no → expiring token
The architecture below shows the main components of a privacy-preserving eligibility flow. It can be used for tickets, access control, benefits or any other binary eligibility question.
Eligibility check request returning yes/no and token
The example below shows a simple HTTP request to a privacy-preserving eligibility endpoint and how to use the response in your application.
// Request
POST https://api.affix-io.com/eligibility/check
Authorization: Bearer AFFIXIO_API_KEY
Content-Type: application/json
{
"program_id": "travel-subsidy-v1",
"subject_id": "user-12345-hash",
"context": {
"route": "CITY-A_CITY-B",
"channel": "web",
"request_id": "req_01H..."
}
}
// Response
{
"eligible": true,
"reason": "within_income_band",
"token": "elig_eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...",
"expires_at": "2026-03-16T12:00:00Z"
}
// Application usage (TypeScript)
const res = await fetch('/api/eligibility/check', { /* proxy to AffixIO */ });
const body = await res.json();
if (!body.eligible) {
showIneligibleMessage(body.reason);
} else {
applySubsidyToBasket();
attachEligibilityToken(body.token);
}For more on yes/no-only patterns that avoid local data storage, see Binary Eligibility Verification Without Storing Personal Data.
Questions about privacy-preserving eligibility verification
Typical examples include ticket validity, benefit programs, access tiers, age checks, discount eligibility and feature flags for regulated functionality. Anywhere your downstream system only needs a yes/no answer is a good candidate.
Yes. The complexity lives in AffixIO's rule engine and proof logic. Your application sees the outcome and, optionally, a small set of reason codes for analytics and UX.
This page focuses on the API buyers view. For a deeper conceptual overview of yes/no-only models and data minimisation, see Binary Eligibility Verification Without Storing Personal Data.
Yes. Eligibility tokens can be pre-issued and verified offline at the edge, then synced later. The same patterns used in our offline payment pages can be applied to offline eligibility and access control.
Bring binary, privacy-first eligibility into your stack
AffixIO's eligibility API is built for teams that want clear decisions and strong privacy. It fits naturally alongside our payment and access control layers.