Synthesia discloses in-house billing & usage-metering platform
A Synthesia engineering post details a billing-and-usage-metering system the team built in-house in ~3 months and ran on roughly one engineer while scaling from $40M to ~$140M ARR, including the 2025 move to a unified credit-based model. Stripe is kept strictly as the payment provider behind an isolated data model; Salesforce remains the CRM. The metering layer is built, not bought.
In a February 2026 engineering blog post (“How We Built a Billing System That Scaled with Us from $40M ARR to ~$140M”), Synthesia software engineer Boian Tzonev describes the company’s in-house billing and usage-metering system. Key disclosures: the system was built in ~3 months, migrated over $40M in usage onto the new model about a month later, and was maintained almost entirely by one engineer over three years. Usage metering is an immutable, audit-logged event store (e.g. “five minutes of video generation have been used at a given point in time”). In 2025 Synthesia transitioned all payment plans to a credit-based system. Third-party tools are deliberately isolated: “Stripe is our payment provider” (payments only) and “Salesforce was our CRM” — both kept behind independent data models for flexibility.
Source: https://www.synthesia.io/post/how-we-scaled-our-billing-system-from-40m-to-140m-arr