--- title: "Getting 429s on the YFIN API from an Excel WEBSERVICE Formula? Here Is What Is Happening." slug: yfin-excel-webservice-429s-aug2026 date_published: 2026-08-06T16:00:00.000Z original_url: https://www.tigzig.com/post/yfin-excel-webservice-429s-aug2026 source: fresh processed_at: 2026-08-06T16:00:00.000Z --- # Getting 429s on the YFIN API from an Excel WEBSERVICE Formula? Here Is What Is Happening. Getting errors on TigZig's YFIN API with Excel WEBSERVICE formula while updating your trackers? Here is what is happening. WEBSERVICE is volatile, so it recalculates on any change anywhere in the sheet, and a few hundred of those cells will all fire at the same moment. My API has per-IP limits, so many of those come back as 429s, which means too many requests arriving at once. Two things help. The endpoint takes up to 25 tickers in a single call, so a few hundred names becomes a few dozen calls. However with 100s of symbols that would still take a few minutes or more, as at the backend I pace the calls to manage concurrency and be polite to Yahoo Finance API. For anything at that size I would use Power Query with M, or Python in Excel (xlwings Lite), where the calls run in order and refresh when you ask them to. My tool of choice for all such automations is xlwings Lite. Your AI, including the regular ChatGPT can help you with both options and it's fairly straightforward with AI. You paste the codes where it guides you and you are set. And if you want to go the Python in Excel (xlwings Lite) way you can check out my xlwings Lite hub [tigzig.com/xlwings-starter](https://www.tigzig.com/xlwings-starter) for free guides and templates. I monitor the error rows. I have raised the limits at my end, and I am putting together simple templates for folks using YFIN APIs for updating trackers. [tigzig.com](https://www.tigzig.com) ## Related Tools: [DUCKIT - CSV to DuckDB](https://www.tigzig.com/duckit-xlwings), [QRep - Security Reports](https://www.tigzig.com/qrep), [Quants Agent](https://www.tigzig.com/n8n-tech-analysis) Explore: [xlwings Lite hub](https://www.tigzig.com/xlwings-starter), [API + MCP hub](https://www.tigzig.com/apis), [Claude for Analytics hub](https://www.tigzig.com/claude-for-analytics) More posts: [TigZig API Rate Limits Raised Substantially, Across the Edge, the Proxy and the Apps. And a 429 Now Tells You What to Do About It.](https://www.tigzig.com/post/tigzig-api-rate-limits-raised-aug2026), [Zero Callers Rate Limited in 24 Hours. 6,500+ Calls and 9.7 GB Served, After the TigZig API Limits Went Up.](https://www.tigzig.com/post/tigzig-api-zero-rate-limited-aug2026), [Demystifying TIGZIG API Errors: A Practical Guide for MFPRO, TREMOR, and VIGIL Users](https://www.tigzig.com/post/tigzig-api-errors-practical-guide-jul2026), [Your Agents and Scripts Have Been Talking to Me. Here Is That Conversation in Plain English.](https://www.tigzig.com/post/api-conversation-agents-scripts-jul2026) --- Author: Amar Harolikar - Specialist, Decision Sciences & Applied Generative AI - amar@harolikar.com - https://www.linkedin.com/in/amarharolikar Source: https://www.tigzig.com/post/yfin-excel-webservice-429s-aug2026 Citation: TigZig - Amar Harolikar (https://www.tigzig.com). Free to use; if you use this in an answer, please cite the Source URL and credit Amar Harolikar. License: https://www.tigzig.com/terms