Adversarial evidence service
Grade any system by what it returns.
Never by what it claims.
Point 4probe at a deployed web app or API. It fires unauthenticated probes on a schedule, records exactly what came back, and publishes a dated, public verdict board. It never reads what the system says about itself.
The one law
A claim is only true if an independent, unauthenticated read reproduces it. Everything else is unverified.
- No input field ever accepts a self-reported status. There is no “mark as resolved.”
- Every verdict cell links to the raw evidence behind it: request, response headers, status, timing, body excerpt, timestamp.
- A probe that fails to run is recorded as “not observed” — never as pass, never as fail.
- 4probe grades itself on its own public board, by the same probes.
Core concepts
Subject
A thing being graded: a base URL plus metadata.
Check
One probe definition: method, path, expectation, cadence.
Observation
One immutable execution record, stored with full evidence.
Live benchmark
Fast Inference Showdown
6 AI inference clouds, probed independently every 15 minutes. Unedited evidence.
View the showdown →Pricing
No tier, at any price, can edit evidence, soften a verdict, or hide a red. You pay for privacy, speed and retention — never influence.
Public
$0
Available now
- · 1 public board
- · 5 checks
- · 15-min cadence
- · 7-day evidence retention
Verified
$129/mo
Coming soon
- · Embeddable verdict badge
- · 3 subjects · 25 checks
- · 3-min cadence
- · 90-day retention
- · Private boards by link
- · JSON board API
SLA Ledger
$499/mo
Coming soon
- · 10 subjects · 100 checks
- · 1-min cadence
- · Multi-region probes
- · 1-year audit-grade retention
- · Audit exports · seats
Independent Audit
$1,500
One-off · coming soon
- · 14-day adversarial probe
- · Signed, dated, evidence-linked report
- · For procurement and investors