One client path. Multiple comparison targets.
Runs continue until you pause, stop, or complete them. The application keeps its existing connection while a bounded dispatcher evaluates every contender off the response path.
Client traffic
Applications keep their existing protocol connection.
Crucible on an Eve interlay
Serves the application and correlates per-request evidence across contenders.
Serving route
Authoritative responseSymmetric contenders
Head-to-head evidenceComparison evidence
Make compatibility decisions with observed behavior.
Every accepted request gets one parent event and one safe observation per contender, without raw SQL or result values.
Latency
Separate queue delay, endpoint dispatch, and total comparison time.
Errors
See target failures without turning them into client failures.
Semantics
Use canonical consensus, outcome-only, or performance-only evidence by protocol.
Completeness
See saturation, timeouts, write gaps, and deliberate safety skips.
Protocol coverage
Compare what the protocol can safely represent.
Crucible records deliberate skips when a request cannot be compared safely. A skip is evidence about coverage, not a silent failure.
See protocol behaviorPostgreSQL
Canonical evidence for safe simple-query reads and writes, with explicit transaction and session skips.
MySQL
Canonical evidence for eligible direct protocol frames with pinned and transactional state excluded.
MongoDB
Stable BSON canonicalization for eligible commands without retaining returned documents.
Redis
Outcome-only evidence for commands and pipelines under the current drain-only response profile.
LLM gateway
Performance-only provider evidence for latency, time to first token, token units, availability, and cost.
Safety boundary
Bounded comparison. Explicit selection.
Target failures and storage pressure never delay the serving response. Completion preflight verifies the selected contender and interlay revision before changing the endpoint.
- Same organization and endpoint kind
- Bounded nonblocking handoff
- Protocol-specific evidence semantics
- Persisted write gaps and guarded completion
Data must already be ready
Crucible can select an endpoint behind the existing interlay, and it can mirror eligible writes best effort, but it does not replicate or synchronize data. Use Exodus when the target needs data movement, guaranteed write capture, cutover gates, or rollback.
Explore ExodusRun the comparison as long as the decision needs.
Inspect the aggregate ranking, drill into individual requests, and complete the run with one endpoint behind the same interlay.