In the world of payments, we spend enormous effort securing transactions—encryption, tokenization, fraud checks, velocity rules, reconciliation logic.
Yet one critical piece is often overlooked:
The link itself.
Payment links, webhook URLs, callback endpoints, redirect URLs—these are frequently treated as disposable utilities. Shortened, shared, forwarded, logged, cached, and reused with little thought to long-term risk.
That’s a mistake.
The Hidden Risk of “Dumb” Links
In real-world payment systems, links are not neutral. They are entry points.
A single short URL can:
- Trigger a payment flow
- Expose a webhook endpoint
- Redirect a user to a sensitive resource
- Act as a bridge between systems
Traditional URL shorteners were never designed for this environment. They optimize for brevity, not control.
Common problems I’ve seen in production systems:
- Links reused beyond their intended lifecycle
- Payment URLs shared outside their original context
- No way to disable or revoke a link once issued
- Zero visibility into who accessed what—and when
- No policy enforcement (time, referrer, purpose, environment)
In payments, that’s unacceptable.
Links Are State — Treat Them That Way
A payment system understands state:
- Pending
- Approved
- Voided
- Refunded
- Expired
But most links are still treated as stateless strings.
That disconnect causes real damage:
- Duplicate payment attempts
- Stale callbacks hitting live endpoints
- Inconsistent reconciliation
- Security exposure during retries or failures
If we treat transactions as stateful objects, links must be stateful too.
From Observing Failures to Building a Solution
While working on systems to prevent duplicate transactions, I repeatedly ran into the same pattern:
The transaction logic was sound—but the URL layer was blind.
Links had no awareness of:
- Which environment they belonged to (dev, stage, prod)
- Whether the transaction they pointed to was still valid
- Whether access should be allowed now, or ever again
That realization led to the creation of relinkit.io.
What a Payment-Aware Link Layer Looks Like
Instead of asking “How short is the link?”, the better question is:
“What rules does this link enforce?”
A smarter URL layer should support:
- Policies (time-bound, purpose-bound, environment-bound)
- Revocation (kill a link instantly)
- Auditability (who accessed it, from where, and when)
- Context awareness (why the link exists)
- API-first design (not just a UI shortcut)
In other words: links should behave more like controlled resources, not disposable shortcuts.
Why This Matters for Duplicate Transactions
Duplicate transactions rarely happen because of one bug.
They happen because multiple weak points align:
- A retry fires
- A callback repeats
- A link remains valid longer than intended
- State is assumed instead of verified
When links are controlled, logged, and revocable, one entire class of errors disappears.
You don’t just reduce fraud risk—you reduce operational noise.
The Bigger Picture
Payments are evolving fast:
- More APIs
- More integrations
- More automation
- More surface area for failure
The systems that succeed will be the ones that treat every layer—including URLs—as first-class infrastructure.
Not everything needs to be reinvented.
But some assumptions need to be retired.
Closing Thought
A short link may look harmless.
In a payment system, it’s anything but.
If you’re building or maintaining payment flows, ask yourself:
Do my links know when they should stop working?
If the answer is no, that’s a gap worth closing.
Kourosh
