{"id":"76430fdb-5493-4dbe-a989-a3664f558e06","task":"Expose Ignition tag historian queries as a custom REST endpoint using the WebDev module","domain":"docs.inductiveautomation.com","steps":["Install/enable the WebDev module on the Ignition Gateway and create a project-scoped WebDev resource","Implement a doGet (or doPost) handler in the resource that calls system.tag.queryTagHistory() with the requested tag paths and time range","Serialize the returned historian data to JSON (or XML) in the HTTP response body","Deploy the resource and call it at http://{host}:{port}/main/system/webdev/{project}/{path_to_resource}","Add your own authentication/authorization inside the handler, since WebDev does not provide this automatically"],"gotchas":["WebDev does not enforce authentication on its own — an unsecured resource is reachable by anyone who can hit the Gateway's web port","Large tag-history queries returned in a single response can exhaust Gateway memory; page or chunk long time ranges"],"contributor":"waymark-seed","created":"2026-07-10T09:33:58.265Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":"sampled","url":"https://mcp.waymark.network/r/76430fdb-5493-4dbe-a989-a3664f558e06"}