API & SYSTEMS INTEGRATION

THE ENGAGEMENT

Fixed price: $3,900. Timeline: 3 weeks. ~20 hours of build.

You connect the client's existing systems — APIs, databases, third-party services, internal tools — into one working whole. Data flows where it should, automatically, with proof it works.

THE $3,900 MATH

20 hours × $190 = $3,800, plus $100 fixed-price buffer. If scope exceeds 20 hours, that's a change order — never free work.

PHASE 1 — DISCOVERY & MAPPING (Days 1–3)

DO

• Inventory every system: what exists, who owns it, what it does
• Map every data flow: where data is born, where it dies, where it gets stuck
• List every manual step: copy-paste between systems, CSV exports, "Sarah does it by hand"
• Document every API: docs quality, auth method, rate limits, reliability reputation
• Identify the money flows: which integrations touch revenue, customers, or compliance

DELIVERABLE

Systems Map — one diagram showing every system, every flow, every manual gap. Plus a written Integration Spec: what connects to what, in what order, and why.

Client signs the spec before you build. No signature, no build.

PHASE 2 — ARCHITECTURE & DESIGN (Days 4–7)

DO

• Design the API contracts first — OpenAPI specs before code
• Choose the integration pattern per flow: real-time (webhooks/events) vs batch (scheduled sync)
• Design data contracts: field mappings, transformations, canonical formats
• Plan failure handling: retries with backoff, dead-letter queues, idempotency keys
• Define the auth strategy: API keys, OAuth2, service accounts — least privilege

DELIVERABLE

Design Document — architecture diagram, OpenAPI specs, data contract tables, failure-handling plan, auth matrix.

DESIGN STANDARDS (non-negotiable)

• REST: nouns not verbs, proper status codes, versioned (/v1/), paginated lists
• Idempotency: every write operation safe to retry
• Webhooks over polling wherever the provider supports it
• Every integration logs structured events: what moved, when, success/fail
• No credentials in code — secrets manager only, from day one

PHASE 3 — BUILD (Days 8–14)

DO

• Build in flow order: highest revenue impact first
• Each integration: connector → transform → deliver → verify
• Retries with exponential backoff on every external call
• Dead-letter queue for anything that fails after retries — nothing silently drops
• Structured logging on every flow from the first commit

DELIVERABLE

Working integrations in the client's staging environment, each demonstrated live.

Demo every Friday. Client sees progress weekly — no big-bang reveal.

PHASE 4 — TEST & HARDEN (Days 15–17)

DO

• Happy-path test: every flow, end to end, with real data shapes
• Failure drill: kill each dependency — does the system degrade or die?
• Duplicate delivery test: fire every webhook twice — is the result idempotent?
• Rate limit test: what happens at the provider's ceiling?
• Load test the pipeline at 10x expected volume

DELIVERABLE

Test Report — every test, every result, every fix applied. Nothing ships with a known failure.

PHASE 5 — DOCS & HANDOFF (Days 18–21)

DO

• API documentation: every endpoint, every field, every error code
• Runbook: the top 5 failure modes and exactly what to do for each
• Architecture diagram updated to as-built
• Credentials inventory: what exists, where it lives, rotation schedule
• 60-minute handoff call — walk their team through everything, recorded

DELIVERABLE

Handoff Package — docs, diagrams, runbook, recording. Their team can run it without you.

IN SCOPE / OUT OF SCOPE

IN SCOPE

• Up to 5 systems / 8 integration flows
• API design + OpenAPI specs
• Data pipelines: ETL/ELT, scheduled or event-driven
• Third-party integrations (CRM, payments, comms, etc.)
• Monitoring, alerting, runbooks, docs, handoff call

OUT OF SCOPE (change order)

• More than 5 systems or 8 flows
• Custom application development beyond integration glue
• Data migration / backfill over 1M records
• Ongoing maintenance (that's the retainer: $1,900/mo)

FULFILLMENT CHECKLIST

• ☐ Proposal signed + 50% deposit ($1,950) received
• ☐ Access granted: repos, cloud accounts, API credentials, docs
• ☐ Systems Map + Integration Spec delivered, client signed
• ☐ Design Document approved
• ☐ Weekly demos done (2 minimum)
• ☐ Test Report: all green
• ☐ Handoff Package delivered + call recorded
• ☐ Balance invoice ($1,950) sent