Open source · MIT License · Local-first · CI/CD ready

Validate entire system behaviors before production failures occur.

System Graph maps how your services are supposed to work. OpenTelemetry captures what they actually do. The LLM generates scenarios, explains failures, and adapts tests automatically.

✓ Open source✓ Local-first, no cloud required✓ Multi-protocol✓ CI/CD ready
A new category

From testing to validation.

Testing asks: "Did the test pass?" Validation asks: "Is the system correct?" These are fundamentally different questions.

Traditional testing
  • Test isolated endpoints
  • Assert HTTP status codes
  • Mock external dependencies
  • Pass/fail per request
  • Coverage measured by lines of code
  • Catch regressions after the fact
System validation
  • Validate full service interaction chains
  • Assert correct events, DB state, and timing
  • Run against real system behavior via OTel
  • Pass/fail per system scenario
  • Coverage measured by real production flows
  • Prevent incorrect system behavior before deploy

The category TestMesh creates

System Validation Platform

Not a QA tool. Not a testing framework. Not an API tester. A platform that understands your architecture, observes real system behavior, and automatically validates that your entire backend is correct — on every deploy.

Distributed systems have a validation gap.

Modern backends are distributed, event-driven, and complex. Testing is still endpoint-based, manual, and incomplete.

01

No system-level testing exists

Teams test APIs, UIs, and units — but nobody tests service interactions, event flows, or data consistency across the full chain. The system behavior between services is a blind spot.

service interactionsevent flowsdata consistency
02

"Works locally, breaks in prod"

Distributed systems fail in ways unit and API tests cannot catch: async timing, partial failures, retry storms, race conditions. These only surface under real system behavior.

async behaviorretry stormsrace conditions
03

QA cannot keep up with engineering speed

Manual integration testing is too slow and too expensive to run on every deploy. Automation exists for UI flows and endpoints — but backend correctness across services remains largely unverified.

manual testingincomplete coverageslow feedback
04

Observability shows what happened — not what should happen

Datadog and Grafana tell you a service crashed. They cannot tell you whether the system behaved correctly. Monitoring is not validation.

DatadogGrafanamonitoring ≠ validation

Not just a test runner. A validation system.

Three layers of intelligence work together to validate your entire distributed system — not individual endpoints.

01Structure

System Graph

Maps how the system is supposed to work — services, APIs, queues, and databases and their relationships. The source of truth for what correct behavior looks like.

02Reality

Telemetry

Uses OpenTelemetry to observe real-time behavior across your distributed system and detect drift from the expected graph.

03Intelligence

LLM

Generates test scenarios from your actual traffic, explains failures in plain language, and adapts your test suite automatically when the system changes.

Visual Interface

Your test suite as a living diagram.

Build and debug integration tests on a spatial canvas. Each action is a node — HTTP, Kafka, Redis, gRPC — connected by bezier curves that show data flow. Click any node to configure it. The YAML syncs in real time.

Spatial Canvas
Pan, zoom, and arrange nodes on an infinite canvas. Flows are diagrams, not text files.
Two-way YAML Sync
Edit in the canvas or the YAML drawer — changes propagate instantly in both directions.
Live Execution
Status overlays update in real time as each step executes. Failures pin to the exact node.
Automatic Flow Discovery

Your system already knows what to test.

When OpenTelemetry is connected, TestMesh detects real flows from live traffic — API call chains, Kafka fan-outs, cache patterns — and generates a test suite from actual behavior rather than assumptions.

  • Detects multi-service call chains from OTel traces
  • Identifies Kafka fan-out patterns automatically
  • Flags untested paths appearing in production traffic
discovered-order-flow.yaml
flow:
  name: "Discovered: Order Lifecycle"
  # Auto-generated from OTel trace 2026-04-14T09:32:11Z
  steps:
    - id: create_order
      action: http_request
      config:
        method: POST
        url: "{{BASE_URL}}/orders"
      assert:
        - status == 201
      output:
        order_id: $.body.id

    - id: verify_event
      action: kafka_consumer
      config:
        topic: "order-events"
        timeout: 10s
      assert:
        - messages[0].value.order_id == "{{order_id}}"

Agentic scenario generation.

TestMesh reads your system graph, observes real traffic, and generates the scenarios that actually matter — not the ones a developer thought to write.

Generated automatically

  • Happy pathFull successful flow across all services
  • Failure scenariosTimeout, retry, partial failure, cascade
  • Edge casesEmpty payloads, duplicate events, out-of-order messages
  • Load patternsBurst traffic, consumer lag, backpressure

CI/CD integration

Runs on every deploy. Blocks broken releases.

Drop TestMesh into your pipeline. On each deploy, it re-validates the full system graph against real behavior. A single incorrect interaction blocks the release.

# GitHub Actions
- name: Validate system
run: testmesh run --ci
✓ 47 scenarios passed
✗ Deploy blocked: 1 failure

Real coverage

Coverage based on reality — not lines of code.

TestMesh measures what percentage of your real production flows are validated. Not which lines were executed. Fake coverage metrics don't catch production failures.

Order lifecycle94%
Payment processing81%
Notification fanout47%
Inventory sync12%

Self-adapting flows

When your system changes — a new service, a renamed event, a schema migration — TestMesh detects the drift and updates affected flows automatically. No broken tests after every refactor.

Built for when things go wrong.

Not just finding failures — understanding them.

Failure Simulation

Inject faults directly into flows to validate degradation behavior before it happens in production.

  • Kafka message delays and partition failures
  • Database connection timeouts
  • Network latency and packet loss
  • Retry storm simulation
🔍

Root Cause Analysis

When a flow fails, TestMesh diffs the Expected Graph against the Actual OTel Trace and pins the exact divergence point.

Expected:
order-service → kafka → inventory-service
Actual:
order-service → kafka → timeout after 5s
↳ inventory-service consumer group lag: 48,231 messages

Every protocol your stack uses

HTTP & REST

Assert status, headers, and body with expr-lang expressions.

action: http_request

Kafka

Produce messages and consume to verify async event flows.

action: kafka_consumer

Databases

Query PostgreSQL directly and assert on rows after API calls.

action: database_query

gRPC

Call unary and streaming gRPC services by method name.

action: grpc_call

WebSocket

Connect, send messages, and assert received payloads.

action: websocket

Redis

Read and assert cache values after service operations.

action: redis_get

From zero to tested in 3 minutes

Install the CLI, write a flow, run it. That's it.

terminal
# macOS / Linux
curl -fsSL https://testmesh.io/install.sh | sh

# Homebrew
brew install test-mesh/brew/testmesh

# npm
npm install -g @testmesh/cli

testmesh --help

What actually breaks in production — and what you test today.

Postman, k6, and Cypress are excellent tools. None of them validate system behavior. That gap is what TestMesh fills.

Validation requirementPostman / k6 / CypressTestMesh
Correct services were called in the right order✗ No✓ Yes
Correct Kafka events were emitted with correct payloads✗ No✓ Yes
Database state is correct after the full chain executes✗ No✓ Yes
Retries and timeouts behave correctly under failure✗ No✓ Yes
Race conditions and partial failures are handled✗ No✓ Yes
All downstream side effects occurred (cache, notifications, etc.)✗ No✓ Yes
Individual API endpoints return correct status codes✓ Yes
Services pass their own unit tests✓ Yes

Keep using your existing tools for what they're good at. Add TestMesh for what they can't do.

Coming soon

TestMesh Cloud

Multi-tenancy, SSO, AI agents, GitHub integration, and a hosted control plane — built on the same OSS engine. One-click deployment, zero infrastructure to manage.

Multi-tenancy
SSO / SAML
AI agents
GitHub integration
Watch this space →

Stop testing protocols in isolation.

Write one flow that validates the whole chain.