Common communication protocols

1) Why does the ecosystem need uniform protocols

The ecosystem consists of operators, studios/RGS, aggregators, PSP/APM, KYC/AML providers, affiliates and analytical services. Common interaction protocols exclude the "zoo" of integrations, speed up onboarding, reduce the cost of support and the risks of incidents, and also provide compatibility when scaling (horizontal, vertical and diagonal).

Objectives: interoperability out of the box, predictable SLOs, data security, replicable migrations.

2) Transport layer and formats

HTTP/2/3, gRPC - for synchronous APIs with low latency; WebSocket - for streaming events/leaderboards; WebRTC (SRTP/QUIC) - for audio/video live content.

• JSON - external B2B APIs and webhooks (readability).
• Protobuf/Avro - internal bus/deep integrations (compression/circuit evolution).
• Compression/binding: gzip/br for JSON; zstd for Protobuf/Avro.
• Local/time: ISO-8601 in UTC, amounts in minimum monetary units (integer).

3) Authentication, authorization, trust

OAuth2/OIDC for client/partner applications (short-lived tokens, PKCE, scopes).
mTLS for S2S between trusted zones JWS/HMAC - signature of requests and webhooks.
RBAC/ABAC: roles and attributes (jurisdiction, tenant, risk level).
Keys and rotation: KMS/Vault, short life, automatic rotation (including JWKS).
Egress control, allow-list domains and ASN, DNSSEC/DoT/DoH in sensitive areas.
Tenant isolation: per-tenant keys, quotas, limits, namespace in the tire.

4) API Contracts (REST/gRPC) - Canon

Versioning: '/v {n} 'in URI for REST;' package. vN 'for gRPC. Minor evolution - flawless; breaking changes - through the new major. Depression by policy (see § 12).
Idempotency: 'Idempotency-Key' on POST/PUT/PATCH cash/critical operations; saving for N hours.
Pagination: cursors ('nextPageToken'), not 'offset/limit'; consistent sorting.
Limits: '429 Too Many Requests' + quota headers ('X-RateLimit-'), jitter in retras.
Errors: machine-readable codes/subcodes, 'correlationId', validation field map.
Timeouts and retreats: exponential delay + jitter; do not retract unsafe errors.
Compatibility policy: immutability of field meaning; new fields - optional.

5) Event Model and Bus (EDA)

Schema Registry: contract for each event, evolution with backward compatibility.

• `click`, `session`, `bet`/`spin`, `round_start`/`round_result`,
• `deposit`/`withdrawal`, `psp_auth`, `kyc_status`, `fraud_signal`,
• `reward_granted`, `leaderboard_update`, `feature_toggle`.
• Party keys: 'playerId', 'campaignId', 'tableId', 'operatorId' (selection by domain).
• Delivery: at-least-once with business idempotency; for monetary totals - saga/txn-outbox.
• Order: "guaranteed order inside the key," cross-keys - through orchestration.
• Time semantics: 'eventTime' + 'ingestTime'; grandfather to '(eventId' idempotencyKey) '.

6) Webhooks and Delivery Guarantees

Signature: JWS/HMAC with't '(timestamp) and' kid ', window check ± 5 minutes, replay is prohibited.
Retrai: backoff with jitter up to T minutes, fixing attempts, resending only at 5xx/timeout.

Idempotency: 'eventId' + body signature; processing "at least once."

Webhook Event Registry: resampling history when out of sync.
Security: mTLS as far as possible, allow-list IP/ASN, CSRF does not apply to server-side collars.

7) Data and privacy (Privacy-by-Design)

PII minimization: tokenization of identifiers ('playerId' is pseudonymized), separation of data domains.
Data contracts: DPA/DPIA, goals, retention periods, cross-border flows (Whitelist countries).
Audit/lineage policies: who/when/why; immutable logs (WORM).
RG/ethics rules: prohibition of aggressive offers for vulnerable segments; a clear legal framework.

8) Consistency and transactions

Strong consistency - purse/balances/payouts.
Eventual - showcases, leaderboards, telemetry.
Sagas for distributed business transactions; compensation for cancellations.
Exactly-once in business sense: idempotent keys and deterministic handlers.

9) Observability and SLO

Tracing: end-to-end 'traceId' from click/webhook to payout/reward; propagation (`W3C traceparent`).
Metrics: p50/p95/p99 API, broker lag, CR payments/CCL, leaderboards E2E.
Logs: structured, without personal data; token/key masking.
SLO-lists: login p95 ≤ 300-500 ms; deposit p95 ≤ 1. 5–2. 0 s; bet/spin p95 ≤ 150-250 ms; event delivery ≥ 99. 9%.

10) Performance, quotas, storm protection

Rate limiting (token/leaky bucket) on L7 and in mesh policies.
Backpressure: queues before fragile upstream (PSP/KYC).
Outlier-ejection: automatic "cooling" of unstable backends.
Circuit-breaker - Closes the thread when error/latency thresholds are exceeded.
Fair-share: quotas by tenant/channel/region; priority of critical domains.

11) SDK compatibility and test criteria

SDK: HTTP/gRPC clients, request signing, jitter retrays, idempotency, cursors.
Contract tests: Postman/Newman/gRPC-conformance, PSP/KYC/studio simulators.
Compatibility matrix: API/SDK versions, supported schemas, decrement policies.
Synthetics: event and transaction generators, 24/7 black boxes for monitoring.

12) Versioning and deposition (Change Management)

Major releases every N months, with a parallel window ≥ 6-12 months.
Minor changes - adding optional fields/methods is frictionless.
Decrement: announcement → warning in headers/responses → flag in metrics → shutdown according to plan.
Event schema migrations - add-only strategy + proxy adapters at boundaries.

13) Protocol security

Zero Trust: mTLS everywhere, short-lived creeds, principles of least privilege.
Secret scopes: separation of read/write/administration keys.
Protection against repetition: nonce/time window in signatures; prohibition of reuse.
WAF/bot filters: protection against scraping/click fraud; low false positive.
Vendor zones: microsegmentation, individual VPCs/namespaces, egress-allow-list.

14) Incidents and DRs

War-room procedures: stop button for domains (content/PSP/KYC), RACI, SLA per trace packet.
DR scenarios: asset-input points (Anycast/GSLB), cut-over ≤ 60-90 s, quarterly exercises.
RCA: templates without finding the culprit, L3↔L7 communication, updates to the/SDK/Runbook protocol.

15) Protocol Success Metrics

Compatibility: the proportion of partners who passed conformance tests; onboarding time (TTO).
Reliability: uptime integrations, p95 API/bus, share of successful webhooks.
Security: PD incidents = 0, key rotation time, share of mTLS traffic.
Economy: cost per rps/txn/event, Cost-to-Serve decline, migration times.
Product: FTD/ARPU/LTV uplift from standardization (fewer CCD/payment leaks).

16) Anti-patterns

"Free form" of events: lack of diagrams and versions → driving around showcases and analytics.
Single L7 gateway without N + 1: SPOF and narrow throat for webhooks/PSP.
Retrai Unlimited/Jitter: Traffic Storm, Transaction Double.
Raw PD in exchange: no tokenization/DPIA → regulatory risks.
Offset pagination: gaps/duplicates under load.
Secrets "forever" and static IP without egress control.
Breaking changes without parallel window and adapters.

17) Implementation checklist

1. Accept the API canon (versioning, idempotency, pagination, errors).
2. Enter Schema Registry and domain map of topic/party keys.
3. Oblige mTLS + JWS/HMAC for S2S and webhooks; automate key rotation/JWKS.
4. Set up limits/retrays/CB/outlier-ejection and quotas per-tenant.
5. Expand tracing/metrics/logs with a single 'traceId'; approve SLO lists.
6. Sign DPA/DPIA, enable tokenization, and store/delete policies.
7. Create SDK and conformance set; Fix the depletion policy.
8. Conduct DR/chaos exercises and war-room rituals; "black start" on the minimum set.
9. Implement a protocol catalog (partner portal): spec, examples, simulators, sandbox.

18) Evolution Roadmap

v1 (Foundation): REST/gRPC canon, basic event schemas, webhook signatures, mTLS.
v2 (Integration): migration pipeline, conformance tests, SDK, rule-engine for quotas/retrays.
v3 (Automation): autodosing by SLI, self-service sandboxes/simulators, adapters between versions.
v4 (Networked Governance): cross-partner protocol committee, shared SLOs/credits/penalties, joint PoP/edge policies.

Brief Summary

Common protocols of interaction are the "language" of the ecosystem: uniform API and event contracts, strict security (mTLS/JWS), idempotency and delivery guarantees, observability and SLOs, managed migrations and DR. Following the canon, participants are more rapid, fall less often, scale more easily and grow predictably - subject to privacy and jurisdictional requirements.