Alex Kim
Backend Engineer
At EveryInfra Alex works on idempotent charging and the refund flow.
Education
- University of Illinois Urbana-Champaign, B.S. Computer Science (2011–2015)
Previous roles
- Stripe (San Francisco) — Software Engineer → Staff (2015–2024)
Articles by Alex Kim
- API Idempotency Key Test: AI Agent Tool Call Retry Without Double Charges
Same Idempotency-Key sent 3 times, charged once. Changed params got a 409. No key, sync resend: charged twice. 20 live calls plus agent retry settings.
- Serper API Pricing Explained: Four Packs, Expiry and Real Cost per 1,000
Serper's four packs kept the same price since 2022, but in 2023 its credits started to expire after 6 months. We model five usage shapes for the real cost.
- Serper API Free Tier: How Long 2,500 Queries Last, and What Comes Next
Serper gives 2,500 free queries with no card and no stated end date. After that the floor is $50. At 1,000 searches a month, year one costs $100 vs $10.