Is there any rate limiting on inbound messages through bot framework?

Digvendra Singh Tomar 0 Reputation points
2026-09-28T08:36:34.3366667+00:00

I found this documentation regarding rate limits for app using bot framework - https://learn.microsoft.com/en-us/microsoftteams/platform/bots/how-to/rate-limit. However, it seems to be applicable to outbound messages from our service backend to MS Teams. Is there any similar rate limiting for messages being pushed to our backend from Teams conversations?

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  1. AI answer

    2026-09-28T08:36:48.44+00:00

    Yes. Inbound traffic through Bot Framework can be rate limited.

    Supported details:

    • When requests are throttled, Bot Framework returns HTTP 429 Too Many Requests.
    • A throttled response can include a Retry-After header that indicates how many seconds to wait before retrying.
    • The documented causes include:
      1. A bot sends messages too frequently
      2. A client of a bot sends messages too frequently
      3. Direct Line clients request a new Web Socket too frequently

    That means rate limiting is not only about outbound bot sends to Teams. It can also apply when a client of the bot is sending too frequently.

    What is not published is a fixed numeric limit for general Bot Framework inbound traffic. The documented guidance states that thresholds are continuously tuned and the numbers aren’t published.

    For Teams-specific bot APIs, all incoming requests to the bot APIs are subject to the same rate limiting policy, and apps that exceed the limit receive HTTP 429. The guidance is to implement retry handling with exponential backoff, and also retry 412, 502, and 504 where applicable.

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  2. Sai Kiran Mudavath 90 Reputation points Microsoft External Staff Moderator
    2026-09-28T11:52:06.3+00:00

    Hi @Digvendra Singh Tomar ,

    Yes, rate limiting can occur in Bot Framework scenarios, including high-volume client/bot activity. However, there is an important distinction regarding the direction of the traffic.

    In your scenario, users are sending messages from Microsoft Teams to your bot's messaging endpoint. Microsoft documents that when a user sends a message, the Bot Framework Connector POSTs an Activity to the endpoint configured for the bot.

    Microsoft does not currently publish a fixed numeric rate limit specifically for Teams user messages delivered inbound to the bot's messaging endpoint. Therefore, the published Teams limits such as the 50 RPS application limit should not be interpreted as an inbound Teams → bot limit. Those documented limits apply to traffic generated by the bot/agent toward Teams APIs, including sending messages and other Bot/Teams API operations.

    For bot/agent requests to Teams, Microsoft documents HTTP 429 Too Many Requests throttling and recommends honoring the Retry-After header and using exponential backoff with jitter. The published values can also change over time, so applications should not hard-code them as permanent limits.

    For your specific Teams → bot inbound scenario, if you are seeing dropped, delayed, or throttled messages, I recommend checking:

    The timestamps and approximate inbound message rate during the incident.

    The HTTP status returned by your messaging endpoint and any responses generated by the Bot Framework/Teams channel.

    Azure Application Insights or application logs for the bot to determine whether the requests reached your endpoint successfully and how they were processed.

    Whether the issue occurs only during high-concurrency/load-test scenarios.

    If you can share the observed behavior, timestamps, HTTP status codes, and any Retry-After information, we can narrow down whether the throttling is occurring on the inbound delivery path, within the bot/application, or when the bot subsequently calls Teams APIs.

    References:
    Send and receive messages with the Bot Connector API
    Rate limiting for agents - Microsoft Teams
    Conversations with an Agent - Microsoft Teams

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