--- title: "Getting a 429 From the MF NAV API? It Is Almost Never the Total. Two Changes Fix Nearly Every Case." slug: mf-nav-api-429-rate-limit-aug2026 date_published: 2026-08-30T12:00:00.000Z original_url: https://www.tigzig.com/post/mf-nav-api-429-rate-limit-aug2026 source: fresh processed_at: 2026-08-30T12:00:00.000Z --- # Getting a 429 From the MF NAV API? It Is Almost Never the Total. Two Changes Fix Nearly Every Case. Getting rate limited with a 429 from the Tigzig MF NAV API? Here is what is usually going on. The limit is 300 requests a minute from one address, and most people who run into it are nowhere near that. The total is rarely the problem. What causes it is everything going out at the same instant, with each call unbounded. A fifty-fund call with no date range might pull over 100,000 rows, and a burst of those trips my backend burst protection, so you get a 429. ## Two changes fix nearly every case **Batch your funds.** One call accepts up to 50 scheme codes, so `schemes=A,B,C` gives you fifty funds in a single request. A hundred separate calls becomes two. **Bound the dates.** Ask for a scheme with no date at all and you get its entire history back to 2006, every day of it. Add `latest=true` if you only want today's NAV, or `since=2026-01-01` for a window. On the same fifty funds that took a request from 4.7 seconds down to 0.3, and from 3.7 MB down to 22 KB. ## By tool **Excel WEBSERVICE.** Put fifty codes in one cell instead of one formula per fund. Every formula fires again on every recalculation, so a sheet with a hundred of them is making a hundred calls each time you touch it. **n8n.** The HTTP Request node has a Batching option with a batch size and an interval, and it is probably switched off by default. **Python or any script.** Fifty at a time, with a small pause between batches. **Power Query.** Usually fine already, because it runs one step after another. ## Check the response The 429 response itself tells you what to do. It has a reason field naming which limit you hit, a suggestion pointing at the exact endpoint to use, and a `retry_after_seconds`. ## Have your AI debug it Copy the whole error into whatever AI agent you build with and ask it to fix your calls. Point it at the docs: [api.tigzig.com/mf/v1/openapi.json](https://api.tigzig.com/mf/v1/openapi.json). It has everything it needs to do that. For my own work, whether it is n8n, Flowise, an Excel formula, Power Query, M code or Python in Excel (xlwings Lite), I have Claude Code do it end to end. It builds the workflow, deploys it, tests it and debugs it. I still do my own validations, but it does the heavy lifting. Should work with any AI coder, Codex, Antigravity and the rest. Docs hub: [tigzig.com/apis/mf-nav](https://www.tigzig.com/apis/mf-nav) ## Some useful guides to debug API errors You can copy the page as markdown and hand it over to your AI. **Demystifying TIGZIG API Errors: A Practical Guide for MFPRO, TREMOR, and VIGIL Users.** [tigzig.com/post/tigzig-api-errors-practical-guide-jul2026](https://www.tigzig.com/post/tigzig-api-errors-practical-guide-jul2026) **MF NAV API FAQ. Why Am I Getting an Error, Why Is There No SIF NAV, and Why Does the AUM Look Wrong?** [tigzig.com/post/mf-nav-api-faq-aug2026](https://www.tigzig.com/post/mf-nav-api-faq-aug2026) ![Getting a 429 from the MF NAV API](/images/blog/mf_nav_api.png) ## Related Tools: [MFPRO - Mutual Fund Analytics](https://www.tigzig.com/mfpro), [MF File Converter](https://www.tigzig.com/mf-files-ai), [DUCKIT - CSV to DuckDB](https://www.tigzig.com/duckit-xlwings) Explore: [MF NAV API docs](https://www.tigzig.com/apis/mf-nav), [API and MCP catalog](https://www.tigzig.com/apis), [Claude for Analytics hub](https://www.tigzig.com/claude-for-analytics) More posts: [Demystifying TIGZIG API Errors: A Practical Guide for MFPRO, TREMOR, and VIGIL Users](https://www.tigzig.com/post/tigzig-api-errors-practical-guide-jul2026), [MF NAV API FAQ. Why Am I Getting an Error, Why Is There No SIF NAV, and Why Does the AUM Look Wrong?](https://www.tigzig.com/post/mf-nav-api-faq-aug2026), [Running Hundreds of API Calls to Pull NAV History, One Scheme Per Call? Batch 50 Into One.](https://www.tigzig.com/post/mfpro-nav-batch-calls-and-guides-aug2026), [Three Upgrades on the India Mutual Fund NAV API. Easier to Pull, Whatever You Already Use.](https://www.tigzig.com/post/mf-nav-api-three-upgrades-aug2026), [Pulling Indian Mutual Fund NAVs One Scheme at a Time? Three Ways to Get the Same Data in Far Fewer Calls.](https://www.tigzig.com/post/mfpro-nav-fewer-calls-batch-files-parquet-aug2026) --- Author: Amar Harolikar - Specialist, Decision Sciences & Applied Generative AI - amar@harolikar.com - https://www.linkedin.com/in/amarharolikar Source: https://www.tigzig.com/post/mf-nav-api-429-rate-limit-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