Senior Python / FastAPI Engineer - Ad-Platform API Integrations (Meta, Google Ads, DV360 + more)

About the work We run an internal marketing-operations platform ("the Hub") that syncs advertising data — advertisers, pixels, conversion tags, and performance — out of a dozen ad platforms into a central database. The backend is a Python service layer on Google Cloud (FastAPI + Cloud Run + Cloud SQL/Postgres). We’re converting older ETL scripts that ran as scheduled jobs into individual FastAPI applications and then adding a brand-new capability: programmatically creating conversion tags/pixels directly in the ad platforms (today everything is read-only). We're looking for a senior backend engineer to help our team deliver this in two phases. Phase 1: Standardize & expand the integrations * Convert our remaining ad-platform integrations from the legacy batch-job style to our established FastAPI service pattern (a reference implementation already exists for you to follow). * Build several net-new read-sync integrations to the same pattern. * Platforms in scope include the following, broken out by current state: * For Review: Google Ads, Reddit, Yahoo * Conversion Required: Meta, DV360, Campaign Manager 360, LinkedIn, Amazon Ads/DSP, The Trade Desk, Snapchat * Not Started: Pinterest, Microsoft (Bing) Ads, Cadent, Realize (Taboola) Phase 2 — Tag-creation write endpoints * Design and build endpoints that create conversion tags / pixels / custom conversions inside the ad platforms via their write APIs. * Start with the 2-3 highest-value platforms, then expand. Includes handling each platform's write scopes, app-review/elevated-access requirements, and idempotency. Additional Details Tech stack * Python 3.13, FastAPI, Pydantic * SQLAlchemy with Alembic migrations PostgreSQL 16GCP resources: Cloud Run services, Cloud Run jobs, Cloud SQL, Cloud Build, Cloud Tasks, Cloud Scheduler, Artifact Registry, Secret Manager * pytest and testcontainers * Terraform and Terragrunt You must have * Deep production Python + FastAPI + SQLAlchemy experience. * Proven, hands-on work with at least two major advertising platform APIs — especially Meta Marketing API, Google Ads API (GAQL + mutates), or DV360/Campaign Manager (Floodlight). Tell us which and what you built. * Real experience with OAuth2 flows, token refresh, and rate-limit handling against third-party APIs across multiple instances * Experience with the relevant Google Cloud resources used in the tech stack. * Strong testing discipline, clean PR-based collaboration, and the ability to write code that is clean, modular, and performant. Nice to have * Experience writing to ad-platform APIs (creating conversion actions, custom conversions, pixels, floodlight activities). * Familiarity with ad-platform app-review / elevated-access processes (Meta Business verification, Google Ads developer token standard access, etc.). * Familiarity with one or more of the net-new platforms (Pinterest, Microsoft Ads, Taboola, Yahoo, Cadent). How we work * We use Git for version control. You will work on feature branches → PRs; our team reviews, merges, and owns deployments. * You code against dev resources (separate dev database, dev secrets, dev service accounts) and test/sandbox ad accounts. * Daily async updates; some working-hours overlap with North America (ET) preferred.