Inspired by the concept of invariant-driven automated testing: instead of only checking payload shape, APOPHIS encodes intended behavior as executable contracts and verifies them with property-based and stateful testing.

Supported Node.js versions: >=20.18.1 (20.x) and 22.x.

npm install @apophis/fastify fastify @fastify/swagger
npx apophis init --preset safe-ci
npx apophis verify --profile quick --routes "POST /users"

x-ensures is an OpenAPI schema extension for behavioral contracts — statements about what a route must guarantee.

Cross-Route Failure Example

Add one behavioral contract next to a route schema. APOPHIS can verify cross-route behavior, such as whether a resource created by one route is retrievable through another.

Route:

import crypto from 'crypto';

app.post('/users', {
  schema: {
    'x-category': 'constructor',
    'x-ensures': [
      // BEHAVIORAL: Creating a user must make it retrievable
      'response_code(GET /users/{response_body(this).id}) == 200'
    ]
  }
}, async (request, reply) => {
  const { name } = request.body;
  const id = `usr-${crypto.createHash('sha256').update(name).digest('hex').slice(0, 8)}`;
  reply.status(201);
  return { id, name };
});

APOPHIS output:

Contract violation
POST /users
Profile: quick
Seed: 42

Expected
  response_code(GET /users/{response_body(this).id}) == 200

Observed
  GET /users/usr-7d865e returned 404

Why this matters
  The resource created by POST /users is not retrievable.

Replay
  apophis replay --artifact reports/apophis/failure-2026-04-28T12-30-22Z.json

Next
  Check the create/read consistency for POST /users and GET /users/{id}.

JSON Schema cannot express this relationship. APOPHIS turns it into an executable check.

Three Modes

Mode	Purpose	Default Environments
`verify`	Deterministic CI and local contract verification	local, test, CI
`observe`	Runtime visibility and drift detection without blocking	staging, prod
`qualify`	Exercise scenarios, stateful flows, and configured chaos checks before release	local, test, staging

Quickstart: 3 Commands

# 1. Install
npm install @apophis/fastify fastify @fastify/swagger

# 2. Scaffold
npx apophis init --preset safe-ci

# 3. Verify
npx apophis verify --profile quick --routes "POST /users"

# 4. Doctor
npx apophis doctor

See docs/getting-started.md for the full walkthrough.

Trust and Safety

Deterministic replay: Every failure includes a seed and a one-command replay.
Explicit test budget: Control how many tests run with runs: 10 in your preset.
CI-safe default path: verify is deterministic and safe for CI pipelines.
Machine-readable output: --format json-summary and --format ndjson-summary for CI dashboards.
Production-safe observe path: observe is non-blocking by default. Blocking behavior requires explicit break-glass policy.
Qualify path gated away from prod: qualify is blocked in production by default.
Monorepo workspace support: --workspace fans out verify and doctor across all packages.
Explicit environment boundaries: Config rejects unknown keys and unsafe environment mixes.

LLM-Safe

APOPHIS gives coding agents a constrained, repeatable way to encode and verify behavior:

Official scaffolds (safe-ci, llm-safe, platform-observe, protocol-lab)
apophis doctor checks for missing dependencies, malformed config, and unsafe modes
CI policy guards catch unknown keys, unsafe environments, and missing seeds
Generated code follows the same pattern in every repo

See docs/llm-safe-adoption.md for templates and CI policy.

Full Documentation

Getting Started — First route, first verify run, first replay
CLI Reference — All 7 commands, global flags, exit codes
Verify Mode — Deterministic contract verification
Observe Mode — Runtime visibility and drift detection
Qualify Mode — Scenarios, stateful testing, chaos
Quality Engines — Chaos injection, flake detection, mutation testing
Performance — Repeatable benchmarks and CPU profiling
LLM-Safe Adoption — Scaffolds and CI guards
Protocol Extensions — JWT, X.509, SPIFFE, WIMSE

Recommended Integration

New projects: Use createFastify() to ensure route discovery is installed before any routes are registered.

import { createFastify } from '@apophis/fastify'

const app = await createFastify({
  logger: true,
  apophis: {
    runtime: process.env.NODE_ENV === 'test' ? 'error' : 'off',
    observe: process.env.NODE_ENV === 'production'
      ? { enabled: true, sampling: 0.1, sinks: [metricsSink] } // your ObserveSink
      : undefined,
  },
})
// Register swagger, auth, plugins, and routes after app creation.

Existing projects: Register APOPHIS or install route discovery before routes. Run apophis doctor to verify routes are discovered with full schema metadata.

Schema-less fallback: If APOPHIS is registered after routes, printRoutes() can recover paths but not route schemas or behavioral contracts. apophis doctor and apophis verify will warn when discovery is schema-less.

Current Limitations

These reflect current implementation behavior. All are actively tracked for improvement.

Route discovery requires ordering. If the APOPHIS plugin or route discovery hook is not installed before routes are registered, behavioral contract annotations (x-ensures, x-requires, x-outbound, x-variants, x-timeout) cannot be recovered. Use createFastify() for new projects or register APOPHIS early.
Observe is programmatic. Register apophisPlugin with observe: { enabled: true, sinks: [...] } for non-blocking contract evaluation on live traffic. Use apophis doctor --mode observe to validate config before deploying. See docs/observe.md.
CLI verify samples once per contract by default. Set runs in your preset to increase the number of property-based test samples per route. The programmatic fastify.apophis.contract() API supports the same runs configuration.
Outbound mocks are process-global. The mock runtime patches globalThis.fetch. Only one mock runtime can be installed at a time. Run mock-dependent tests serially or isolate by process. Undici MockAgent integration is not yet implemented.
Qualify coverage depends on profile configuration. Qualify runs scenario, stateful, and chaos checks based on profile gates. Chaos route selection uses the configured strategy (one/all/sample/routes).

Compatibility

Fastify v5 only. Fastify v4 and earlier are not supported.
ESM only. This package is "type": "module" and does not provide a CommonJS build. Use import syntax.
Node.js >=20.18.1 <21 || >=22 <23.
@fastify/swagger must be registered before routes (APOPHIS auto-registers it if missing).

License

MIT