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Kristina A.
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Kristina A.

API Development SME Engineer - Custom Builds & System Integrations

US-Based Principal Engineer | Zero Outsourcing | 25+ Years in the Trenches I provide the technical certainty that only comes from longevity. With over 100 projects completed on Upwork and experience dating back to the earliest days of the web, I build robust backend architecture that works the first time. I Make Systems Talk to Each Other — HubSpot, Jobber, WooCommerce, Mailchimp, Salesforce, FieldAware, Workyard, and more. If your CRM, website, or field-service tools aren't syncing the way they should, that's exactly the problem I solve. Recent Work: • HubSpot & Jobber Sync — a custom Python listener and PHP-based integration automating real-time client sync (Create/Update) and job lifecycle automation via high-performance webhooks, built when Zapier and native integrations weren't cutting it. • Custom WordPress Booking Plugin — full Jobber GraphQL API integration for a service-industry client, including a self-service cancel/reschedule flow, taken from early development through staging acceptance. • Field Service Software Integration — built in Airtable with TypeScript automations, connecting two different field-service management platforms (FieldAware and Workyard) so job and crew data flow between them automatically • Large-Scale Data Pipeline — a Python/PHP deduplication and normalization pipeline for a veteran employment nonprofit, processing 113 files and roughly 79,600 records. • Commercial Product Development — authored and released a WooCommerce/Authorize.net payment gateway plugin (CIM vaulting, auth-only checkout with manual capture, subscription billing, debug logging) with LemonSqueezy license management, plus a Python Gmail API bulk mailer tool. Core Expertise: • Python & FastAPI — modern, asynchronous, strictly typed APIs • API Integration & ETL — REST, GraphQL, and legacy SOAP services • PHP & Backend Systems — custom architecture, Laravel, and database optimization • Data Architecture — custom SQL design and complex JSON transformations Why Work With Me: You are hiring a Subject Matter Expert, not a junior developer. I do not outsource, I do not subcontract, and I do not require hand-holding. I translate business requirements into production-ready code that is documented and resilient.

🇺🇸St. Petersburg, United States$85/hr100% JSS4.55 (86)Since Sep 2015

Earnings and projects

MRR
$636

Last 6 months ÷ 6

World#67,822 / 412k
🇺🇸Country#10,351 / 62.1k
Revenue, last 30 days
$200

Last 6 months: $3.8k

World#81,881 / 412k
🇺🇸Country#10,372 / 62.1k
Total earnings
$208k

Billed in all: $210k

World#14,480 / 412k
🇺🇸Country#3,553 / 62.1k
Per project
$1.8k

$764 in the last 6 months

World#83,702 / 412k
🇺🇸Country#14,109 / 62.1k
Projects, last 6 months
5

Across 7 contracts

29% fixed71% hourly
World#41,746 / 412k
🇺🇸Country#5,872 / 62.1k
Projects in all
116

Across 132 contracts

41% fixed59% hourly
World#22,782 / 412k
🇺🇸Country#3,680 / 62.1k

Earnings, last 30 days

$210k+$200 earned in the last 30 daysBilled in all, before Upwork's fee · drag across the chart to see what was earned in any stretch
$210.0k$210.1k$210.2k$210.3kOct 8Oct 23Nov 7

Skill rankings: Top 10% in AJAX

Ranked by MRR among everyone on Upwork with the skill.

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  4. #159JSON1,293 freelancers · 🇺🇸 #21Top 12%
  5. #203AJAX2,006 freelancers · 🇺🇸 #10Top 10%
  6. #823WordPress Plugin5,436 freelancers · 🇺🇸 #103Top 15%
  7. #999jQuery8,973 freelancers · 🇺🇸 #76Top 11%
  8. #1,233API7,943 freelancers · 🇺🇸 #150Top 16%