Architecture Overview

Last reviewed: 2026-11-05. Update this page when you add, move or remove a service. The source of truth is terraform/. For what data goes where and which third parties receive it, see Data Flows.

Production

Components

Component	Runs on	What it does	Terraform
Web app	Vercel	Next.js dashboard, checkout and customer portal on `polar.sh`	`modules/vercel`
API	Render	FastAPI backend behind `api.polar.sh`. Also serves checkout link redirects on `buy.polar.sh`	`modules/render_service`
Dramatiq workers	Render	Background jobs and the scheduler, one service per queue	`modules/render_service`
Lambda task workers	AWS	Background jobs consumed from SQS, one queue and function per priority	`modules/aws_task_worker`
Postgres	PlanetScale	Primary for writes, a dedicated read replica for reads, both behind PgBouncer	`modules/planetscale_postgres`
Redis	AWS ElastiCache	Cache and the Dramatiq broker. Render reaches it over PrivateLink	`modules/aws_redis`, `modules/redis_private_link`
S3	AWS	Uploaded files, invoices, receipts and payout invoices	`modules/s3_buckets`
KMS	AWS	Secret encryption and JWKS signing keys	`modules/render_secrets_kms`, `modules/jwks_signing_key`
Cloudflare	Cloudflare	DNS for `polar.sh`, proxy and TLS for the API and web app, the MCP Worker	`production/*.tf`
Backoffice	Render	Internal admin UI on `backoffice.polar.sh`, reachable only over Tailscale	`modules/render_service`
Tailscale router	AWS EC2	Engineer access to the private VPC, Redis and the database	`modules/ec2_tailscale`

Environments

Production, sandbox and test each have their own Terraform workspace in terraform/production, terraform/sandbox and terraform/test. The diagram above shows production. Sandbox and test use the same modules but omit production-only components: the MCP Worker, the dedicated read replica and the backup copy job. Sizes, domains and the number of workers also differ.

Company

Working at Polar

Design

Engineering

Production

Components

Environments

​Production

​Components

​Environments

Production

Components

Environments