Technical Guide June 12, 2023 3 min read

API-First for B2B Platforms: Architecture Decisions Behind DekaFlow

How we designed DekaFlow as an API-first platform — OpenAPI specification, versioning, rate limiting, and developer experience.

Deka Technology
Software Engineering
API-firstDekaFlowRESTOpenAPI

When Deka Technology's product team sat down to design DekaFlow — our B2B workflow automation platform — the first architectural decision was also the most consequential: adopt an API-first design philosophy from day one. In enterprise environments, platforms that treat APIs as an afterthought pay a steep price. Integration debt accumulates faster than technical debt, and DACH enterprise clients pay the price in delayed go-lives and brittle connections.

What API-First Actually Means

API-first is not simply "write an API." It means the API contract is designed, reviewed, and agreed upon before a single line of implementation code is written. For DekaFlow, this meant producing an OpenAPI 3.1 specification first — defining every endpoint, schema, error code, and example payload — and subjecting that spec to a design review involving our architects, the product team, and a sample of target B2B clients.

The benefit is immediate: frontend engineers, backend engineers, and third-party integration partners can all work in parallel against the contract, using mock servers generated directly from the spec. On DekaFlow, this parallel workflow significantly reduced integration time compared to a traditional sequential approach.

Versioning Strategy: Why We Chose URL-Based Versioning

Three versioning strategies dominate API design: URL-based (/v1/, /v2/), header-based (Accept: application/vnd.deka.v2+json), and query parameter-based. For enterprise B2B clients, we consistently recommend URL-based versioning and apply it in DekaFlow for three reasons:

  • Visibility: Operations teams and API gateways can route by URL without inspecting headers.
  • Cacheability: CDN and proxy layers cache /v1/ and /v2/ independently without custom Vary headers.
  • Explicitness: Enterprise procurement and audit teams can document exact endpoint versions referenced in SLAs.

DekaFlow maintains two active major versions simultaneously, with a 12-month deprecation notice and automated deprecation warnings surfaced in the developer portal.

Stay ahead in enterprise tech.

Get our latest insights — no spam, unsubscribe anytime.

Rate Limiting Design for B2B Traffic Patterns

Consumer APIs throttle per user. B2B APIs throttle per tenant, per resource tier, and per endpoint family — the patterns are fundamentally different. DekaFlow implements a token bucket algorithm with three dimensions: tenant-level burst allowance, per-endpoint sustained throughput, and a global safety valve to protect the cluster under cascading load. Clients receive X-RateLimit-Remaining and Retry-After headers on every response, and quota dashboards surface in the developer portal in real time.

Authentication: OAuth2 for Human Flows, API Keys for Machine-to-Machine

DekaFlow supports both authentication patterns. Human users authenticate via OAuth2 Authorization Code flow with PKCE, integrated with clients' existing identity providers (Entra ID, Okta, and on-premise LDAP via SAML bridge). Machine-to-machine integrations — ERP connectors, data pipelines, automated provisioning — use scoped API keys with configurable expiry and rotation reminders.

The most reliable enterprise integration is one where every credentials rotation event is automated, audited, and zero-downtime. DekaFlow's key management API enables clients to rotate credentials programmatically without manual portal intervention.

SDK Generation and the Developer Portal

From a single OpenAPI spec, we generate typed SDKs for TypeScript, Python, and Java using OpenAPI Generator, with Deka-maintained templates that enforce consistent error handling and retry logic. The DekaFlow developer portal — built on Stoplight Elements — renders interactive documentation, provides a sandbox environment backed by deterministic test fixtures, and links directly to the changelog for each API version. Engineers contribute to the spec in pull requests; the portal updates on every merge.

The result is an API platform that enterprise B2B clients can onboard to in days rather than weeks — and one that survives the reality of long-running DACH enterprise contracts where integration partners change, ERP versions upgrade, and compliance requirements evolve.

API-firstDekaFlowRESTOpenAPIB2Bplatform architecture
Share

Want to learn more about this topic?

First consultation is free — no strings attached.

Talk to our experts
All articles
Related Articles
Technical Guide

FieldSales: Offline-First Architecture for 45,000 Field Representatives

How we built our FieldSales platform with offline-first design for areas without network coverage — synchronization, conflict resolution, and lessons learned.

Technical Guide

DekaFlow: How We Built an Enterprise BPM Platform with Camunda

The architecture decisions behind DekaFlow — our Camunda-based BPM platform for process automation in enterprise environments.

Technical Guide

.NET Legacy Modernization: How We Gradually Replace Monolithic Systems

Our proven approach to gradually modernizing .NET monoliths — Strangler Fig pattern, domain-driven design, and zero-downtime migration.

Let's build something that works.

First consultation is free.

Get in Touch