Interoperability of participants

(Section: Ecosystem and Network)

1) What is interoperability of participants

Interoperability - the ability of different organizations (operators, studios, PSP, KYC/AML providers, bridges, affiliates, analysts and governances) to reliably interact with each other through agreed protocols and contracts, while maintaining security, privacy and reproducibility of business results.

• Time-to-integration ↓
• Predictability (stable SLO/SLA by critical flows).
• Security and compliance (minimum sufficient rights, audit).
• Evolution without breakdowns (versioning, backward compatibility).

2) Interoperability levels (layer model)

1. Transport and network: HTTP/2/3, gRPC/QUIC, WebSockets, P2P, mTLS.
2. Identities and trust: org_id, peer_id, X.509/mTLS, signatures, key rotation.
3. Events and data: unified event schemas, asset/network catalogs, idempotency.
4. Processes and business contracts: payout/settlement, attribution, risk signals, limit replication.
5. Management/legal layer: SLA/SLO, DPA, licenses, governorship regulations.
6. Observability and quality: SLI/SLO, logging, tracing, audit.

Each layer has its own contracts, tests, and compatibility policy.

3) Design principles

Contract-first: APIs/schemas/events are formalized before implementation.
Backward-compatible changes: the "add fields only" strategy and the deprecate window ≥ 90 days.
Capability negotiation: Participants exchange supported capabilities and select a common subset.

Isolation and PoLP: access and limits are issued "minimum necessary."

Idempotence and determinism: repeat-safe operations, predictable conflict rules.
Default observability: trace-id correlation of requests/events, verifiable bills.
Data minimization: lack of PII in telemetry/labels, pseudonymization.

4) Capability negotiation

When shaking hands, participants publish a manifesto of features and versions.

yaml participant:
org_id: "ORG:ACME"
versions:
api: "2. 6. 1"
events: "1. 9. 0"
capabilities:
payouts: { create: true, cancel: true, currencies: [USD, EUR, USDC] }
kyc: { level: ["basic","enhanced"], sla_minutes_p95: 15 }
bridge: { proof: ["light","zk"], challenge_supported: true }
telemetry: { qos: ["P0","P1"], traces: true }
limits:
payouts_daily_usd: 1_000_000 rate_limits: { create_per_minute: 500 }

The compatibility engine matches party manifests and selects a work profile (e.g. 'payouts: v2', 'events: v1. 9`).

5) API/Event Contracts and Schemas

API contracts: OpenAPI/gRPC IDL, clear error codes, idempotent keys ('Idempotency-Key'), body constraints.
Event model: 'deposit.', 'payout.', 'bridge.', 'kyc.', 'risk.', 'product.' - with stable fields.
Directories/catalogs: networks, assets, payment methods, SDK versions, regions/jurisdictions.
Data Contracts - tested in CI, changes through governance with timelock.

yaml event:
id: uuid ts: timestamp_utc type: payout. created    payout. finalized    bridge. lock...
src_org: string dst_org: string payload: object trace_id: string idempotency_key: string signature: string # source signature

6) Versioning and compatibility

Semantic versions: 'MAJOR. MINOR. PATCH`.
Rules: MINOR/PATCH - backward-compatible; MAJOR - parallel existence with "adapters," deprecate ≥ 90 days.
Migration playbooks: migration templates for API/events/directories; emulators of old formats.

7) Integration patterns (patterns)

Request-Reply + Idempotency: secure payments/limits/reserves.
Event-Driven: "sources of truth" send out change; subscribers materialize storefronts.
Outbox/Inbox: atomic publishing of events from the database; idempotent reception at the subscriber.
SAGA (orchestration/choreography): coordinated multi-domain operations (for example, "popolneniye→igrovoye sobytiye→vyplata").
Dual-write guard: no direct double entries without an outbox.
Replay/Backfill: failover with order and finalization.

8) Security and trust

mTLS and key binding to 'org _ id/peer _ id'.
Event signatures, trust log (who and what signed/received).
RBAC/ABAC and quotas: rights by role, limits by operation/volume.
Secret management: rotation, prohibition of "long-lived" tokens, short scopes.
PII/privacy: tokenization, regional data segregation (EU/ROW), DSR processes (delete/export).
Protection against abuse: velocity-limits, anti-fraud signals, sanctions checks.

9) SLI/SLO and interoperability observability

• 'p95 Time-to-Acknowledge '.
• 'p95 End-to-End '(create → finalize/execute).
• 'Success Rate'by event/operation type.
• 'Schema/Contract Compliance% '(valid messages).
• 'Proof Coverage% '(proportion of signed/attached evidence).
• `Error Budget Burn` по P0/P1.

• P0 (payout/bridge): p95 E2E ≤ 5 min, Success ≥ 99. 5%, Ack ≤ 2 sec.
• P1 (product): Freshness p95 ≤ 3 min, Compliance ≥ 99. 9%.
• Data contracts: Drift MTTA ≤ 5 min, Breaking changes = 0 without MAJOR.

Дашборды: Interop Ops, Contract Health, Latency & Success, Schema Drift, Security & Keys.

10) Compatibility matrix (test design)

• Scenarios: payouts, deposits, bridge, risk, product, telemetry.
• Versions: API v2. 6/v2. 5, events v1. 9/v1. 8.
• Network modes: normal, degradation, regurgitation, DA delays.
• Jurisdictions: EU/UK/TR/LA - different catalogues and rules.

Autotests: contract tests (producer/consumer), idempotency, retry/compensation, schema-linters, load profiles.

11) Reference schemes and catalogs

Features Catalog (SQL)

sql
CREATE TABLE capabilities (
org_id TEXT,
cap_name TEXT,
version TEXT,
params JSONB,
PRIMARY KEY (org_id, cap_name)
);

Contract/Version Register

sql
CREATE TABLE contracts (
name TEXT, kind TEXT,     -- api    events    catalog version TEXT, status TEXT,  -- active    deprecated    retired breaking BOOLEAN DEFAULT FALSE,
effective_from TIMESTAMPTZ,
deprecates_at TIMESTAMPTZ,
PRIMARY KEY (name, version)
);

Compatibility Monitoring

sql
SELECT name, version, 100. 0SUM(CASE WHEN compliant THEN 1 END)/COUNT() AS compliance_pct
FROM contract_checks
WHERE ts >= now() - INTERVAL '7 days'
GROUP BY name, version;

12) Configurations (YAML)

Versioning policy

yaml versioning:
events: { compatibility: "BACKWARD", deprecate_days: 90 }
api:  { parallel_majors: true, support_minors: 2 }

Idempotency and repeats

yaml idempotency:
header: "Idempotency-Key"
ttl_hours: 72 conflict_policy: "prefer-latest-payload-with-signature"

QoS Classes

yaml qos:
P0: { ack_timeout_ms: 2000, retries: 3, backoff_ms: [100,400,800] }
P1: { ack_timeout_ms: 5000, retries: 2 }
P2: { best_effort: true }

13) Operating procedures

Daily: compliance report on contracts/schemes, expired keys, SLO burn.
Weekly: interoperability committee (new opportunities, migrations, deprecates).
Before release: contract tests, canary with "glass" metrics, rollback plans.
Incidents: single status channel, message templates for partners, post-mortem ≤ 72 h.

14) Playbook incidents

A. Schema/Contract Drift

1. Enable "strict mode" (cut off inappropriate messages),

2. open the incident and notify sources,

3. generate a diff

4. release the adapter/fix,

5. post-mortem and linter update.

B. Bulk replays/double messages

1. Check idempotence/keys,

2. turn on the dedup filters,

3. limit the noisy producer,

4. recalculation of shop windows.

C. Increase in ack latency/drawdown

1. Prioritize P0, increase consumers,

2. temporarily reduce P2 sampling,

3. route and network bottleneck analysis.

D. Member Key Compromise

1. Revoke, rotation, trusted registry update,

2. re-signing of critical batches/certificates,

3. audit of actions, report to partners.

E. Directory mismatch (assets/networks)

1. Quarantine conflict messages,

2. catalog rollback

3. recalculation of aggregates,

4. publishing patches.

15) Implementation checklist

1. Define levels and contracts (APIs, events, directories, keys).
2. Run the capability negotiation and the version/capability register.
3. Include idempotency, quotas, QoS, signatures, and mTLS.
4. Configure SLI/SLO, dashboards and alerts (Ack, E2E, Compliance).
5. Automate contract tests and compatibility test matrix.
6. Enter deprecate and migration procedures (MAJOR in parallel).
7. Regularly review catalogs/privacy and access rules.

16) Glossary

Capability negotiation - reconcile supported capabilities and work profile.
Contract-first - Design interfaces through formal contracts prior to implementation.
Idempotency - repeat-security operations.
Schema/Contract Drift - discrepancy between actual messages and declared contracts.
PoLP is the principle of minimum necessary rights.
Compliance% is the percentage of messages/requests that match the contract.

Bottom line: Participant interoperability is a managed system of contracts, versions, capabilities, and observability. By following this framework, the ecosystem provides fast integrations, sustainable business flows and safe evolution without breakdowns - from the network level and identities to processes and governance.