How to Add Error Handling and Retries to LangGraph Pipelines
Learn how LangGraph's retry, timeout, and error handling mechanisms work together to build resilient pipelines, including customization options, version...
Direct answer
LangGraph uses retries, timeouts (for async nodes), and error handling in sequence to manage node failures. Retries first attempt to rerun failed nodes, then timeouts limit execution time, and error handlers step in after retries are exhausted. Node-level timeouts and error handlers require LangGraph version 1.2 or higher (alpha release).
Building resilient LangGraph pipelines requires effective handling of node failures, and LangGraph provides three core mechanisms—retries, timeouts, and error handling—that operate in a fixed sequence.
Retries are managed via RetryPolicy, which automatically reruns failed nodes. By default, most exceptions are retried except for specific ones like ValueError and TypeError, and HTTP exceptions only when they return 5xx status codes. Developers can customize retry logic with parameters such as maximum attempts, initial interval, backoff factor, maximum interval, jitter, and target exceptions. Inside nodes, runtime.execution_info can be used to check details like the current attempt count.
Timeouts are exclusive to asynchronous nodes; setting them for synchronous nodes results in a compile-time error. They can be configured using the timeout parameter in add_node, accepting values like seconds (number), timedelta, or TimeoutPolicy (separating run timeout—hard limit—and idle timeout—resets on progress). A timeout triggers NodeTimeoutError, clears failed attempt writes, and the retry policy decides whether to retry.
After retries are exhausted, error handlers take over. These recovery functions can handle exceptions by writing alternative summaries to the state or logging details to LangSmith’s custom metadata.
Node-level timeouts and error handlers require LangGraph version 1.2 or higher (alpha release). The default retry policy uses 3 attempts, initial interval of 0.5s, backoff factor of 2.0, max interval of 128s, and jitter enabled.
Sources
- LangGraph Official Documentation: https://docs.langchain.com/llms.txt
- Technical Blog: "LangGraph's Three Fault-Tolerance Tools: Insure Your Agent with Retries, Timeouts, and Error Handlers" (June 22, 2026)
FAQ
- What sequence do LangGraph's failure-handling mechanisms follow?
- When a node fails, the retry policy first decides whether to rerun it. If retries are exhausted, the error handler runs. Timeouts (async only) trigger NodeTimeoutError, which is evaluated by the retry policy.
- Can I set timeouts for synchronous nodes in LangGraph?
- No—timeouts are only applicable to asynchronous nodes. Setting them for synchronous nodes will result in a compile-time error.
- What are LangGraph's default retry parameters?
- The default retry policy includes 3 maximum attempts, an initial interval of 0.5 seconds, a backoff factor of 2.0, a maximum interval of 128 seconds, and jitter enabled by default.