custom api development & integrations

Connect your systems with
high-throughputcustom APIs.

Disconnected software creates data silos and manual entry errors. We build robust, secure REST, GraphQL, and gRPC APIs that seamlessly connect your web apps, mobile platforms, payment gateways, and legacy databases.

Build your API architecture See API capabilities

99.99%

API Uptime

< 20ms

Avg Latency

100%

Contract safe

24/7

Health monitoring

rest & grpc middleware

oauth2 & rate-limited

api.yourcompany.com/v1

Endpoint Status

GET /v1/orders/sync

// Response Payload

{ "status": 200, "latency": "14ms", "synced": true }

Payment Gateway Bridge200 OK

bKash Webhook Listener • 0.00% Error Rate

Payment Gateways/ERP Systems/CRM Platforms/E-Commerce APIs/Legacy Databases

// api engineering

Seamless interoperability for all your tools.

Eliminate data silos with custom middleware built for sub-second payload delivery.

REST, GraphQL & gRPC APIs

High-throughput, backwards-compatible API architectures engineered for high concurrency.

Legacy system integration

Secure middleware adapters connecting modern web applications with legacy databases & ERPs.

Event-driven webhook automation

Real-time message queues (Kafka, RabbitMQ) triggering instant cross-platform workflows.

Bank-grade API security

OAuth2 authentication, rate limiting, payload encryption, and DDoS protection.

Payment & SMS API bridges

Pre-built connectors for bKash, Nagad, SSLCommerz, Twilio, WhatsApp, and Stripe.

Swagger & OpenAPI documentation

Interactive API docs and Postman collections for seamless developer onboarding.

// api engineering roadmap

Six steps to connected software.

A structured integration process from OpenAPI contract design to live monitoring.

DISCOVER

API audit & specs

We review endpoints, payload schemas, rate limits, and auth methods.

DESIGN

Contract specification

Design versioned OpenAPI/Swagger contracts and error-handling specs.

BUILD

Middleware development

Two-week sprints building API adapters, queues, and security layers.

TEST

Load & security testing

Automated load testing, edge case handling, and payload security audits.

LAUNCH

Production deployment

Zero-downtime deployment with active monitoring and alerting.

SUPPORT

Version maintenance

Ongoing SLA monitoring, version upgrades, and third-party API maintenance.

// why custom apis

Custom API Middleware vs. Zapier / Make.

Why high-volume businesses build custom API bridges instead of relying on third-party automation tools.

What matters to you

Custom API Bridge

Zapier / No-Code

Payload speed & latency

< 20ms direct execution

5–15 min delay cycles

Monthly cost per 100k tasks

$0 / fixed server cost

Price scales per task ($$$)

Data privacy & security

Encrypted private cloud

Third-party data logging

Complex logic & retries

Custom failover queues

Fails silently on error

Custom API rate limits

Unlimited throughput

Throttled API quota caps

// integration tech stack

Modern API technologies.

High-concurrency frameworks paired with automated message queue brokers.

API Architecture

RESTGraphQLgRPC / Protobuf

Backend & Middleware

Node.jsGoPython / FastAPI

Caching & Queues

RedisApache KafkaRabbitMQ

// why softzen it

Senior integration engineers.

We engineer API integrations that are robust, secure, and fully documented for your team.

API specialists

Engineers experienced in microservice design, webhook architectures, and payment gateway security.

Fixed milestone delivery

Dated sprint schedule with live OpenAPI/Postman test endpoints.

Zero vendor lock-in

Source code, OpenAPI contracts, and Postman suites belong 100% to you.

Built for high scale

Engineered to handle millions of daily API calls with zero downtime.

// faq

API Integration FAQs.

We build RESTful APIs, GraphQL endpoints, gRPC microservice layers, webhook listeners, payment gateway connectors (Stripe, bKash, SSLCommerz), ERP/CRM bridges, and legacy database sync adapters.

We implement bank-grade OAuth2, OIDC, JWT tokens, API key rate-limiting, HMAC payload signature verification, and TLS 1.3 encryption for all data in transit.

Yes! We regularly build secure middleware adapters that bridge legacy mainframes, SQL Server databases, or custom desktop software with modern cloud web apps.

Our middleware includes automated retry queues (Kafka/RabbitMQ), circuit breaker patterns, and fallback caches (Redis) so your application remains fully functional even during vendor outages.

Yes. Every integration comes with interactive Swagger / OpenAPI 3.0 documentation, Postman collection test suites, and integration code samples.

Let's Engineer Your Next Product Together

Schedule a consultation with our technical architects to discuss your goals, requirements, and deployment timeline.

Start a Project

Connect your systems withhigh-throughputcustom APIs.