Services > API and System Integrations

API AND SYSTEM INTEGRATIONS

API and system integrations, built like real engineering work.

Custom code integrations for the work that does not fit Zapier, Make.com, or n8n. Direct API connections, custom auth flows, webhook architectures, ETL pipelines, and embedded integrations. Production-grade reliability, fully owned by you.

A POST request to /v2/orders with Bearer token authorization. The request body contains a customer_id field set to cust_4823 and an items array. The API responds with 201 Created, returning an order_id of ord_8472 and status of created.

YOUR PRODUCTBackend, app, service
REQUEST
API_INTEGRATION.TS
POST /v2/orders
Authorization: Bearer {api_key}
{
"customer_id": "cust_4823",
"items": [...]
}
<- 201 Created
{
"order_id": "ord_8472",
"status": "created"
}
RESPONSE
THIRD-PARTY APIVendor, SaaS, partner

A real integration in 13 lines of code. We write the rest. Auth, retries, validation, monitoring, deployment.

Book an integration scoping call

Production integrations shipped. Node.js, Python, TypeScript, Go. AWS, GCP, on-prem.

WHEN TO PICK THIS

Four scenarios where no-code stops being the answer.

No-code automation platforms are excellent at what they were designed for: standard integrations between common SaaS tools, run at moderate volume, with simple data transformations and standard auth. When the work moves outside those boundaries, the platforms either cannot do it or do it poorly. The four scenarios below are where we usually get called in.

01

The integration lives inside your product.

When the integration is a feature your customers see, it cannot live in a third-party automation tool. Customer-facing reliability, latency, and brand control all require the integration to run in your own infrastructure as part of your own product code.

TELLTALE SIGN

Your customers experience the integration as part of your software, not as "we use Zapier under the hood."

02

The auth flow is more complicated than an API key.

OAuth 2.0 with refresh token rotation, mTLS, signed webhooks, enterprise SSO, custom JWT handling. The moment the auth model requires real implementation work, no-code platforms either lack support or implement it in ways that fail in edge cases.

TELLTALE SIGN

Your vendor's auth docs are longer than two pages.

03

Volume or latency demands push past what the platform can do.

At very high volume, no-code platforms either become expensive or hit rate limits. At very low latency, the abstractions in no-code platforms add overhead you cannot afford. Custom code lets you tune for the actual constraints.

TELLTALE SIGN

Your integration needs to run in under 200ms, or your monthly task usage on Zapier crossed six figures.

04

The data transformation is genuinely complex.

Iterating over nested arrays, joining responses from multiple APIs, computing derived fields with business logic, validating against a complex schema, denormalizing for a downstream system. At some point, the work becomes engineering work, not configuration work.

TELLTALE SIGN

Your no-code workflow has more than ten Formatter or Function nodes in a single scenario.

INTEGRATION PATTERNS

Six architectures we ship most often.

Most integration work falls into one of six architectural patterns. Picking the right pattern is half the build. The other half is implementing it without skipping the parts that make production reliable.

REST API integration

PATTERN

The default for most modern SaaS integrations. We build clients that handle authentication, pagination, rate limits, retries, and schema validation. Often the foundation that other patterns sit on top of.

Webhook receiver with queue

PATTERN

Accept high-volume webhook events into a queue, process them in workers, handle retries on failure. The right architecture when you cannot guarantee the downstream system will be available when the event fires.

GraphQL aggregation

PATTERN

A single GraphQL endpoint that aggregates data from multiple backend APIs. Reduces round trips for client applications, lets you evolve the API contract without coordinating with every consumer.

ETL data pipeline

PATTERN

Extract from one system, transform with business logic, load into another. Scheduled or event-driven. For data warehouse loads, reporting feeds, or system-to-system migrations that need to run repeatedly.

Event-driven architecture

PATTERN

Publish events to a bus (Kafka, SNS, EventBridge, Pub/Sub). Multiple downstream services subscribe and react independently. The right pattern when one upstream change needs to trigger many downstream actions reliably.

Embedded customer integrations

PATTERN

Integrations your customers configure inside your product to connect their tools. White-labeled, multi-tenant, with secure credential storage and per-customer error isolation. Common in vertical SaaS and platform companies.

AUTHENTICATION

The unsexy part that breaks every integration.

Most integration failures happen in the authentication layer. Tokens expire. Refresh flows break. API keys leak. The five auth methods below cover almost everything we work with. We implement each one with the failure modes baked in.

METHODTYPICAL USEWHAT WE HANDLECOMPLEXITY
API keySimple server-to-server integration. Most SaaS APIs default to this.Secret storage in env vars or vault, rotation, scoped keys per environment
LOW
OAuth 2.0User-authorized integrations. Connecting on behalf of an end user.Full authorization flow, refresh token rotation, scope management, expiry handling, error recovery
HIGH
JWT / signed tokensService-to-service with short-lived credentials. Common in microservice and enterprise architectures.Token generation, signature verification, key rotation, claim validation, clock skew tolerance
MEDIUM
HMAC signed requestsHigh-security webhook verification or partner integrations where request integrity matters.Signature generation and verification, timestamp validation, replay protection, key versioning
MEDIUM
mTLS / certificate-basedRegulated industries, B2B partner integrations, enterprise SaaS with strict security requirements.Certificate provisioning, mutual verification, cert rotation, CA management, fallback handling
VERY HIGH

We have also implemented enterprise SSO (SAML, OIDC), custom auth schemes from legacy systems, and the long tail of one-off auth requirements that show up in real integration work.

REAL PROJECTS

Five integrations we have shipped to production.

Anonymized for client confidentiality. The architecture and decisions are real. The metrics are approximations where exact numbers would identify the client.

B2B SAAS

Embedded Salesforce integration for a vertical SaaS product.

Our client's customers wanted to sync their CRM data into our client's product without IT lift. We built an embedded Salesforce integration where customers connect their own org via OAuth, choose which objects to sync, and the data flows in real-time through webhooks plus a fallback sync.

WHY CUSTOM CODE

Customer-facing reliability and multi-tenant credential storage made no-code platforms unsuitable. The integration is a product feature, not a backend automation.

FINTECH

High-volume webhook receiver with idempotency and replay protection.

A payment processor sending 50,000+ webhook events per day to our client. The existing webhook handler was missing events under load and double-processing on retries. We rebuilt it with proper queue topology, idempotency keys, and replay protection.

WHY CUSTOM CODE

At this volume, no-code platforms either rate-limit or silently drop events. The reliability requirements demanded a real engineering solution with monitoring and dead-letter queues.

HEALTHCARE

HL7 to FHIR bridge for a HIPAA-regulated workflow.

A healthcare client needed to bridge an older HL7-based clinical system with a modern FHIR-compatible application. Required full HIPAA compliance, audit logging of every message, and no third-party data processing.

WHY CUSTOM CODE

HIPAA compliance, custom message format translation, and on-prem deployment requirements ruled out every no-code option. This was bespoke middleware work.

E-COMMERCE

Multi-channel order pipeline aggregating Shopify, Amazon, and three other channels.

An e-commerce brand selling on five channels needed a single internal source of truth for orders. Each channel had different webhook payloads, refund flows, and inventory deduction logic. We built the aggregation layer that normalized everything into a single canonical order model.

WHY CUSTOM CODE

Five distinct schemas, complex deduplication logic, and downstream fulfillment routing made this far beyond what no-code platforms can model cleanly.

B2B SAAS PLATFORM

OAuth provider for a customer-facing integration marketplace.

A SaaS platform wanted to offer customers an integration marketplace where third-party developers could build apps that connect to customer accounts. We built the OAuth provider side of the equation: app registration, consent flows, scoped tokens, revocation, audit logs.

WHY CUSTOM CODE

Being the OAuth provider (not consumer) is engineering work that no-code platforms do not even attempt. This required deep understanding of the OAuth 2.0 spec and PKCE flows.

THE STACK

What we actually build with.

No religion about languages or frameworks. We pick what fits the use case, the team that will inherit the code, and the infrastructure already in place. Below is the spread of what we work with most.

LANGUAGES

Languages and runtimes

Node.jsTypeScriptPythonGoJavaRust

FRAMEWORKS

Frameworks and libraries

ExpressFastifyNestJSFastAPIDjangogRPC

INFRASTRUCTURE

Cloud and runtime

AAWS
Google Cloud
AAzure
Vercel
Cloudflare Workers
Kubernetes
Docker

DATA AND QUEUES

Data stores and queues

Postgres
MongoDB
Redis
MySQL
Kafka
RabbitMQ
SQSBullMQRabbitMQ

OBSERVABILITY AND OPS

Plus the operational stack

DatadogSentryNew RelicPagerDutyGrafanaPrometheusHoneycombOpenTelemetry

PRODUCTION RELIABILITY

Six things we never skip.

The difference between an integration that works in a demo and one that survives in production is the six things below. Skip any of them and the integration becomes someone's problem at 2am within a year. We build them in from day one.

01

Idempotency

Every operation that creates or modifies data should be safe to retry. Network failures happen. Workers crash. Requests time out. Without idempotency, a retry causes duplicate orders, duplicate charges, duplicate emails. We build it in by default.

WHAT WE BUILD IN

Idempotency keys, deduplication windows, exactly-once delivery semantics where possible, at-least-once with safe-to-retry handlers everywhere else

02

Retry logic with backoff

Transient failures are the rule, not the exception. Network blips, vendor API hiccups, rate limit windows. Retries should be smart: exponential backoff, jitter to avoid thundering herd, max retry caps to avoid infinite loops, dead-letter queues for what cannot be saved.

WHAT WE BUILD IN

Exponential backoff with jitter, retry caps (typically 3-5 attempts), dead-letter queue routing after exhaustion, alerting on DLQ growth

03

Rate limit handling

Every third-party API has rate limits. The polite integration respects them. The smart integration uses them as a signal for self-pacing. Our integrations track remaining quota, slow down before hitting the wall, and queue requests instead of hammering the API.

WHAT WE BUILD IN

Token bucket or leaky bucket pacing, 429 response handling, retry-after header respect, per-tenant quota tracking for multi-tenant integrations

04

Monitoring and alerting

If you cannot see it, you cannot fix it. Every integration ships with metrics on throughput, error rate, latency, and queue depth. Alerts fire on anomalies. The first time you know something is wrong is not a customer complaint.

WHAT WE BUILD IN

Per-endpoint metrics, structured logging, error rate alerts, latency p95/p99 alerts, queue depth alerts, runbook documentation for each alert

05

Secret management

API keys, OAuth tokens, signing secrets, certificates. Storing them in env vars or config files is how integrations end up in breach reports. We use proper secret stores with rotation, audit logging, and per-environment isolation.

WHAT WE BUILD IN

AWS Secrets Manager, GCP Secret Manager, HashiCorp Vault, or your existing solution. Per-environment isolation. Rotation hooks built in.

06

Graceful degradation

When a downstream system is down, your integration should not bring down your application. We design for partial failure: feature flags, circuit breakers, fallback paths, cached responses where appropriate. The integration fails softly while the rest of the system keeps running.

WHAT WE BUILD IN

Circuit breaker patterns, timeout budgets, fallback to cached data, feature flag kill-switches, separate failure domains per integration

HOW WE BUILD

Five phases. Engineering reviews at every step.

Integration work that ends up in production needs to be reviewed like production engineering work, not like configuration work. Below is how we build it, including the checkpoints where your team signs off before we move forward.

01

Discovery and scoping

1 WEEK

Map the systems involved, understand the data flows, identify the auth requirements, sketch the architecture options. We document constraints (volume, latency, compliance) before designing anything.

REVIEW POINT

You review and approve the architectural approach before we move to design.

02

Design and contract

1 WEEK

Detailed design: API contracts, data schemas, error handling strategy, deployment topology, monitoring approach. Documented as written specs your team can review like a real design doc.

REVIEW POINT

Your engineering team reviews the design doc. We adjust based on feedback before writing code.

03

Build in dev

2-6 WEEKS

Implementation against the design. Test-driven where it makes sense. Includes unit tests, integration tests, and load tests proportional to the production volume the integration will see.

REVIEW POINT

Code review by your team if you want one. We push to a branch in your repo (or ours) with documented PRs.

04

Production deploy

1-2 WEEKS

Deploy to your staging environment first. Run end-to-end tests with real (test mode) credentials. Cut over to production with monitoring in place from the first minute. Rollback plan documented.

REVIEW POINT

Production cutover happens on a schedule you control, with you in the room or on the call.

05

Handoff and operate

1 WEEK + ONGOING

Full documentation: architecture diagrams, runbooks, incident response procedures, on-call playbook. Optional retainer if you want us to stay on for ongoing operations and improvements.

REVIEW POINT

Your team can either take operations from here or retain us for ongoing support. Both are common.

FAQ

Frequently asked questions.

What engineering leaders ask before signing. Click to expand any answer.

READY TO TALK SHOP

Bring us the integration that does not fit a no-code tool. We build the real thing.

Forty-five minutes. Walk us through the systems involved, the constraints (volume, latency, security, compliance), and what your team has already tried. We will tell you what an integration looks like, what stack we would pick, and what production-grade actually means for your case.

Book an integration scoping call

No pressure. Just value.

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