1. Architectural boundaries

Service boundaries and shared infrastructure. Arrows are aggregated source imports.

Frontend History Matching Worker Persistence API Clients Common Composition SDK CHASM Entrypoints / other

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Temporal upstream

Go packages (not individual files) · 4db93cd73e + local changes

12 nodes · 67 edges · dot layout · Open SVG · DOT · Import evidence · Interactive standalone

100%

Source folders / modules

api — GitHub
27 source units
- api/adminservice/v1 — GitHub
- api/archiver/v1 — GitHub
- api/batch/v1 — GitHub
- api/chasm/v1 — GitHub
- api/checksum/v1 — GitHub
- api/cli/v1 — GitHub
- api/clock/v1 — GitHub
- api/cluster/v1 — GitHub
- api/common/v1 — GitHub
- api/contextpropagation/v1 — GitHub
- api/deployment/v1 — GitHub
- api/enums/v1 — GitHub
- api/errordetails/v1 — GitHub
- api/health/v1 — GitHub
- api/history/v1 — GitHub
- api/historyservice/v1 — GitHub
- api/matchingservice/v1 — GitHub
- api/metrics/v1 — GitHub
- api/namespace/v1 — GitHub
- api/persistence/v1 — GitHub
- api/replication/v1 — GitHub
- api/routing/v1 — GitHub
- api/schedule/v1 — GitHub
- api/taskqueue/v1 — GitHub
- api/token/v1 — GitHub
- api/visibilityservice/v1 — GitHub
- api/workflow/v1 — GitHub
chasm — GitHub
15 source units
- chasm — GitHub
- chasm/lib/activity — GitHub
- chasm/lib/activity/gen/activitypb/v1 — GitHub
- chasm/lib/activity/model — GitHub
- chasm/lib/all — GitHub
- chasm/lib/callback — GitHub
- chasm/lib/callback/gen/callbackpb/v1 — GitHub
- chasm/lib/nexusoperation — GitHub
- chasm/lib/nexusoperation/gen/nexusoperationpb/v1 — GitHub
- chasm/lib/scheduler — GitHub
- chasm/lib/scheduler/gen/schedulerpb/v1 — GitHub
- chasm/lib/scheduler/internal — GitHub
- chasm/lib/scheduler/migration — GitHub
- chasm/lib/workflow — GitHub
- chasm/lib/workflow/gen/workflowpb/v1 — GitHub
client — GitHub
6 source units
- client — GitHub
- client/admin — GitHub
- client/frontend — GitHub
- client/history — GitHub
- client/matching — GitHub
- client/operator — GitHub
common — GitHub
101 source units
- common — GitHub
- common/activityoptions — GitHub
- common/aggregate — GitHub
- common/api — GitHub
- common/archiver — GitHub
- common/archiver/filestore — GitHub
- common/archiver/gcloud — GitHub
- common/archiver/gcloud/connector — GitHub
- common/archiver/provider — GitHub
- common/archiver/s3store — GitHub
- common/auth — GitHub
- common/authorization — GitHub
- common/backoff — GitHub
- common/build — GitHub
- common/cache — GitHub
- common/callbacks — GitHub
- common/channel — GitHub
- common/checksum — GitHub
- common/circuitbreaker — GitHub
- common/clock — GitHub
- common/clock/hybrid_logical_clock — GitHub
- common/cluster — GitHub
- common/codec — GitHub
- common/collection — GitHub
- common/config — GitHub
- common/contextutil — GitHub
- common/convert — GitHub
- common/deadlock — GitHub
- common/debug — GitHub
- common/definition — GitHub
- common/dynamicconfig — GitHub
- common/effect — GitHub
- common/enums — GitHub
- common/failure — GitHub
- common/fastrand — GitHub
- common/finalizer — GitHub
- common/future — GitHub
- common/goro — GitHub
- common/headers — GitHub
- common/health — GitHub
- common/limiter — GitHub
- common/links — GitHub
- common/locks — GitHub
- common/log — GitHub
- common/log/tag — GitHub
- common/masker — GitHub
- common/membership — GitHub
- common/membership/ringpop — GitHub
- common/membership/static — GitHub
- common/metrics — GitHub
- common/metrics/tally/statsd — GitHub
- common/namespace — GitHub
- common/namespace/nsmanager — GitHub
- common/namespace/nsregistry — GitHub
- common/namespace/nsreplication — GitHub
- common/nexus — GitHub
- common/nexus/nexusrpc — GitHub
- common/number — GitHub
- common/payload — GitHub
- common/payloads — GitHub
- common/pingable — GitHub
- common/pprof — GitHub
- common/predicates — GitHub
- common/primitives — GitHub
- common/primitives/timestamp — GitHub
- common/priorities — GitHub
- common/protocol — GitHub
- common/quotas — GitHub
- common/quotas/calculator — GitHub
- common/resolver — GitHub
- common/resource — GitHub
- common/retrypolicy — GitHub
- common/routing — GitHub
- common/rpc — GitHub
- common/rpc/auth — GitHub
- common/rpc/encryption — GitHub
- common/rpc/faultinjection — GitHub
- common/rpc/grpcfaults — GitHub
- common/rpc/httpfaults — GitHub
- common/rpc/interceptor — GitHub
- common/rpc/interceptor/logtags — GitHub
- common/sdk — GitHub
- common/searchattribute — GitHub
- common/searchattribute/sadefs — GitHub
- common/serviceerror — GitHub
- common/shuffle — GitHub
- common/softassert — GitHub
- common/sqlquery — GitHub
- common/stats — GitHub
- common/stream_batcher — GitHub
- common/taskqueue — GitHub
- common/tasks — GitHub
- common/tasktoken — GitHub
- common/telemetry — GitHub
- common/timer — GitHub
- common/tqid — GitHub
- common/util — GitHub
- common/versioninfo — GitHub
- common/wideevents — GitHub
- common/worker_versioning — GitHub
- common/workercommands — GitHub
common/persistence — GitHub
26 source units
- common/persistence — GitHub
- common/persistence/cassandra — GitHub
- common/persistence/client — GitHub
- common/persistence/faultinjection — GitHub
- common/persistence/nosql/nosqlplugin/cassandra/gocql — GitHub
- common/persistence/nosql/nosqlplugin/cassandra/translator — GitHub
- common/persistence/schema — GitHub
- common/persistence/serialization — GitHub
- common/persistence/sql — GitHub
- common/persistence/sql/sqlplugin — GitHub
- common/persistence/sql/sqlplugin/mysql — GitHub
- common/persistence/sql/sqlplugin/mysql/session — GitHub
- common/persistence/sql/sqlplugin/postgresql — GitHub
- common/persistence/sql/sqlplugin/postgresql/driver — GitHub
- common/persistence/sql/sqlplugin/postgresql/session — GitHub
- common/persistence/sql/sqlplugin/sqlite — GitHub
- common/persistence/telemetry — GitHub
- common/persistence/transitionhistory — GitHub
- common/persistence/versionhistory — GitHub
- common/persistence/visibility — GitHub
- common/persistence/visibility/manager — GitHub
- common/persistence/visibility/store — GitHub
- common/persistence/visibility/store/elasticsearch — GitHub
- common/persistence/visibility/store/elasticsearch/client — GitHub
- common/persistence/visibility/store/query — GitHub
- common/persistence/visibility/store/sql — GitHub
service/history — GitHub
82 source units
- service/history — GitHub
- service/history/api — GitHub
- service/history/api/addtasks — GitHub
- service/history/api/deletedlqtasks — GitHub
- service/history/api/deleteexecution — GitHub
- service/history/api/deleteworkflow — GitHub
- service/history/api/describemutablestate — GitHub
- service/history/api/describeworkflow — GitHub
- service/history/api/forcedeleteworkflowexecution — GitHub
- service/history/api/getdlqtasks — GitHub
- service/history/api/getworkflowexecutionhistory — GitHub
- service/history/api/getworkflowexecutionhistoryreverse — GitHub
- service/history/api/getworkflowexecutionrawhistory — GitHub
- service/history/api/getworkflowexecutionrawhistoryv2 — GitHub
- service/history/api/isactivitytaskvalid — GitHub
- service/history/api/isworkflowtaskvalid — GitHub
- service/history/api/listqueues — GitHub
- service/history/api/listtasks — GitHub
- service/history/api/multioperation — GitHub
- service/history/api/pauseactivity — GitHub
- service/history/api/pauseworkflow — GitHub
- service/history/api/polltimeskipping — GitHub
- service/history/api/pollupdate — GitHub
- service/history/api/queryworkflow — GitHub
- service/history/api/reapplyevents — GitHub
- service/history/api/recordactivitytaskheartbeat — GitHub
- service/history/api/recordactivitytaskstarted — GitHub
- service/history/api/recordchildworkflowcompleted — GitHub
- service/history/api/recordworkflowtaskstarted — GitHub
- service/history/api/refreshworkflow — GitHub
- service/history/api/removesignalmutablestate — GitHub
- service/history/api/replication — GitHub
- service/history/api/replicationadmin — GitHub
- service/history/api/requestcancelworkflow — GitHub
- service/history/api/resetactivity — GitHub
- service/history/api/resetstickytaskqueue — GitHub
- service/history/api/resetworkflow — GitHub
- service/history/api/respondactivitytaskcanceled — GitHub
- service/history/api/respondactivitytaskcompleted — GitHub
- service/history/api/respondactivitytaskfailed — GitHub
- service/history/api/respondworkflowtaskcompleted — GitHub
- service/history/api/respondworkflowtaskfailed — GitHub
- service/history/api/scheduleworkflowtask — GitHub
- service/history/api/signalwithstartworkflow — GitHub
- service/history/api/signalworkflow — GitHub
- service/history/api/startworkflow — GitHub
- service/history/api/terminateworkflow — GitHub
- service/history/api/unpauseactivity — GitHub
- service/history/api/unpauseworkflow — GitHub
- service/history/api/updateactivityoptions — GitHub
- service/history/api/updateworkflow — GitHub
- service/history/api/updateworkflowoptions — GitHub
- service/history/api/verifychildworkflowcompletionrecorded — GitHub
- service/history/api/verifyfirstworkflowtaskscheduled — GitHub
- service/history/api/workflowresend — GitHub
- service/history/archival — GitHub
- service/history/circuitbreakerpool — GitHub
- service/history/configs — GitHub
- service/history/consts — GitHub
- service/history/deletemanager — GitHub
- service/history/events — GitHub
- service/history/historybuilder — GitHub
- service/history/hsm — GitHub
- service/history/hsm/callbacks — GitHub
- service/history/hsm/dummy — GitHub
- service/history/hsm/nexusoperations — GitHub
- service/history/hsm/nexusoperations/workflow — GitHub
- service/history/interfaces — GitHub
- service/history/ndc — GitHub
- service/history/notification — GitHub
- service/history/queues — GitHub
- service/history/queues/common — GitHub
- service/history/queues/errors — GitHub
- service/history/replication — GitHub
- service/history/replication/eventhandler — GitHub
- service/history/shard — GitHub
- service/history/tasks — GitHub
- service/history/vclock — GitHub
- service/history/workflow — GitHub
- service/history/workflow/cache — GitHub
- service/history/workflow/matcher — GitHub
- service/history/workflow/update — GitHub
service/worker — GitHub
24 source units
- service/worker — GitHub
- service/worker/addsearchattributes — GitHub
- service/worker/batcher — GitHub
- service/worker/common — GitHub
- service/worker/deletenamespace — GitHub
- service/worker/deletenamespace/deleteexecutions — GitHub
- service/worker/deletenamespace/errors — GitHub
- service/worker/deletenamespace/reclaimresources — GitHub
- service/worker/dlq — GitHub
- service/worker/dummy — GitHub
- service/worker/migration — GitHub
- service/worker/parentclosepolicy — GitHub
- service/worker/replicator — GitHub
- service/worker/scanner — GitHub
- service/worker/scanner/build_ids — GitHub
- service/worker/scanner/executions — GitHub
- service/worker/scanner/executor — GitHub
- service/worker/scanner/history — GitHub
- service/worker/scanner/scheduleinvariants — GitHub
- service/worker/scanner/taskqueue — GitHub
- service/worker/scheduler — GitHub
- service/worker/workerdeployment — GitHub
- service/worker/workerdeployment/replaytester — GitHub
- service/worker/workerdeployment/replaytester/worker — GitHub
temporal — GitHub
2 source units
- temporal — GitHub
- temporal/environment — GitHub
service/frontend — GitHub
2 source units
- service/frontend — GitHub
- service/frontend/configs — GitHub
service/matching — GitHub
5 source units
- service/matching — GitHub
- service/matching/configs — GitHub
- service/matching/counter — GitHub
- service/matching/hooks — GitHub
- service/matching/workers — GitHub
service — GitHub
cmd — GitHub
21 source units
- cmd/server — GitHub
- cmd/tools/cassandra — GitHub
- cmd/tools/check-dependencies — GitHub
- cmd/tools/ci-notify — GitHub
- cmd/tools/codegen — GitHub
- cmd/tools/elasticsearch — GitHub
- cmd/tools/fairsim — GitHub
- cmd/tools/flakereport — GitHub
- cmd/tools/gendynamicconfig — GitHub
- cmd/tools/genroutingkeyextractor — GitHub
- cmd/tools/genrpcserverinterceptors — GitHub
- cmd/tools/genrpcwrappers — GitHub
- cmd/tools/gensearchattributehelpers — GitHub
- cmd/tools/getproto — GitHub
- cmd/tools/optimize-test-sharding — GitHub
- cmd/tools/parallelize — GitHub
- cmd/tools/protoc-gen-go-chasm — GitHub
- cmd/tools/protogen — GitHub
- cmd/tools/sql — GitHub
- cmd/tools/tdbg — GitHub
- cmd/tools/test-runner — GitHub

Temporal concerns

Upstream package ownership context. Concerns by code area. Each entry includes docs, glossary, and owner links.

Concern	Meaning	Owning packages (all contributors)	References
Ack level	The checkpointed position below which all tasks in a category are complete.	`service/history/queues` · diagram · GitHub `service/history/shard` · diagram · GitHub	docs · glossary
Activity Definition / Activity Type	The user function implementing an Activity and the name that maps to it; registered on the worker.	`sdk` · SDK repositories	docs · glossary
Activity Execution	The full chain of attempts for one scheduled Activity, from schedule to final result.	`service/history/workflow` · diagram · GitHub `service/history/api/respondactivitytaskcompleted` · diagram · GitHub `service/history/api/respondactivitytaskfailed` · diagram · GitHub `service/history/api/respondactivitytaskcanceled` · diagram · GitHub `service/history/api/pauseactivity` · diagram · GitHub `service/history/api/resetactivity` · diagram · GitHub `service/history/api/updateactivityoptions` · diagram · GitHub	docs · glossary
Activity Heartbeat	A periodic progress ping recorded in mutable state and checked by the heartbeat timeout timer.	`service/history/api/recordactivitytaskheartbeat` · diagram · GitHub `service/history/queues` · diagram · GitHub	docs · glossary
Activity Task	A task carrying the input and context for one Activity attempt, dispatched by Matching after History schedules it.	`service/history/queues` · diagram · GitHub `service/matching` · diagram · GitHub `service/history/api/recordactivitytaskstarted` · diagram · GitHub `service/history/api/isactivitytaskvalid` · diagram · GitHub	docs · glossary
Archival	Copies closed histories and visibility records to blob storage after retention, driven by the history archival queue.	`common/archiver` · diagram · GitHub `common/archiver/provider` · diagram · GitHub `common/archiver/filestore` · diagram · GitHub `common/archiver/s3store` · diagram · GitHub `common/archiver/gcloud` · diagram · GitHub `service/history/archival` · diagram · GitHub `api/archiver/v1` · diagram · GitHub	docs · glossary
Asynchronous Activity Completion	An Activity returns pending and an external system completes it later by Task Token.	`service/frontend` · diagram · GitHub `service/history/api/respondactivitytaskcompleted` · diagram · GitHub `common/tasktoken` · diagram · GitHub	docs · glossary
Authorizer Plugin / Claim Mapper	Server plugins that extract claims from a JWT and authorize each API call.	`common/authorization` · diagram · GitHub `common/rpc/auth` · diagram · GitHub `common/rpc/encryption` · diagram · GitHub	docs · glossary
Backlog / spool	Tasks persisted because no poller was waiting; classic, priority, and fairness variants.	`service/matching` · diagram · GitHub `common/persistence` · diagram · GitHub `cmd/tools/fairsim` · diagram · GitHub	docs · glossary
Buffered events	Events that arrive while a Workflow Task is in flight, held until the task completes.	`service/history/historybuilder` · diagram · GitHub `service/history/workflow` · diagram · GitHub	docs · glossary
CHASM	Coordinated Heterogeneous Application State Machines: a component-tree framework that lets non-workflow archetypes share the shard substrate.	`chasm` · diagram · GitHub `chasm/lib/workflow` · diagram · GitHub `chasm/lib/all` · diagram · GitHub `service/history` · diagram · GitHub `cmd/tools/protoc-gen-go-chasm` · diagram · GitHub `api/chasm/v1` · diagram · GitHub	docs · glossary
Child Workflow	A workflow started from inside another; the parent is notified of its close through a cross-shard RPC.	`service/history/queues` · diagram · GitHub `service/history/api/recordchildworkflowcompleted` · diagram · GitHub `service/history/api/verifychildworkflowcompletionrecorded` · diagram · GitHub	docs · glossary
Command	A requested action a worker returns after a Workflow Task; the server validates it and writes Events.	`service/history/workflow` · diagram · GitHub `service/history/api/respondworkflowtaskcompleted` · diagram · GitHub	docs · glossary
Continue-As-New	Closes the current run and atomically starts a new run of the same Workflow ID with a fresh Event History.	`service/history/workflow` · diagram · GitHub `service/history/api/respondworkflowtaskcompleted` · diagram · GitHub	docs · glossary
Delay Workflow Execution	A start option that delays the first Workflow Task by a backoff timer.	`service/history/api/startworkflow` · diagram · GitHub `service/history/queues` · diagram · GitHub	docs · glossary
Dual Visibility	Running a secondary Visibility store during a migration.	`common/persistence/visibility/manager` · diagram · GitHub	docs · glossary
Dynamic config	Typed, hot-reloadable settings keyed by namespace, task queue, or shard.	`common/dynamicconfig` · diagram · GitHub `cmd/tools/gendynamicconfig` · diagram · GitHub	docs · glossary
Event	A record the server appends to history from an external occurrence or a Command.	`service/history/historybuilder` · diagram · GitHub `service/history/events` · diagram · GitHub `api/history/v1` · diagram · GitHub	docs · glossary
Event History	The append-only log of Events for one execution, stored as a tree of branches of event batches.	`common/persistence` · diagram · GitHub `service/history/events` · diagram · GitHub `service/history/api/getworkflowexecutionhistory` · diagram · GitHub `service/history/api/getworkflowexecutionrawhistoryv2` · diagram · GitHub	docs · glossary
Failover version / version history	Per-event version numbers tied to the active cluster so replication can detect and resolve conflicting branches.	`common/persistence/versionhistory` · diagram · GitHub `common/cluster` · diagram · GitHub `service/history/ndc` · diagram · GitHub	docs · glossary
Failure / Failure Converter	Temporal's typed error model carried in Events and across SDKs.	`common/failure` · diagram · GitHub `common/serviceerror` · diagram · GitHub `sdk` · SDK repositories `api/errordetails/v1` · diagram · GitHub	docs · glossary
Frontend Service	The stateless gateway that authenticates, rate-limits, validates the namespace, and routes every call to History or Matching.	`service/frontend` · diagram · GitHub `service/frontend/configs` · diagram · GitHub `common/rpc/interceptor` · diagram · GitHub	docs · glossary
Global Namespace / Failover	A namespace replicated to a standby cluster, and the handover of its active cluster.	`common/namespace/nsreplication` · diagram · GitHub `service/worker/replicator` · diagram · GitHub `service/worker/migration` · diagram · GitHub `common/rpc/interceptor` · diagram · GitHub `service/history/shard` · diagram · GitHub	docs · glossary
Heartbeat / Start-To-Close / Schedule-To-Close / Schedule-To-Start Timeouts	Activity timeouts, each persisted as the next timer task per activity and enforced by the timer queue.	`service/history/queues` · diagram · GitHub `service/history/workflow` · diagram · GitHub	docs · glossary
History branch / tree	Executions can fork on reset or conflict resolution; the tree records branches and nodes store event batches.	`common/persistence` · diagram · GitHub `common/persistence/versionhistory` · diagram · GitHub `service/history/ndc` · diagram · GitHub	docs · glossary
History Service	The stateful core that owns execution state and Event History and runs the internal task queues.	`service/history` · diagram · GitHub `service/history/api` · diagram · GitHub `service/history/configs` · diagram · GitHub `api/historyservice/v1` · diagram · GitHub	docs · glossary
History Shard	A fixed-count partition of the execution space, owned by one History host at a time; requests route by hashing namespace and workflow ID.	`service/history/shard` · diagram · GitHub `client/history` · diagram · GitHub `common/persistence` · diagram · GitHub	docs · glossary
HSM (hierarchical state machines)	The older framework for typed state machines inside mutable state, used for callbacks and Nexus operations.	`service/history/hsm` · diagram · GitHub `service/history/hsm/callbacks` · diagram · GitHub `service/history/hsm/nexusoperations` · diagram · GitHub	docs · glossary
Idempotency	Designing Activities so repeats have one effect, because delivery is at-least-once.	`sdk` · SDK repositories	docs · glossary
Internal service clients	Typed gRPC clients between services, layered with metrics and retries, that resolve the owning host through membership.	`client` · diagram · GitHub `client/history` · diagram · GitHub `client/matching` · diagram · GitHub `client/frontend` · diagram · GitHub `client/admin` · diagram · GitHub `client/operator` · diagram · GitHub `common/resource` · diagram · GitHub	docs · glossary
List Filter	The SQL-like query string accepted by list and count APIs.	`common/persistence/visibility/store/query` · diagram · GitHub `common/sqlquery` · diagram · GitHub	docs · glossary
Local Activity	An Activity executed inside the worker's Workflow Task, recorded as a marker Event.	`sdk` · SDK repositories `service/history/workflow` · diagram · GitHub	docs · glossary
Matching Service	Hosts Task Queues and matches tasks from History to worker long-polls, in memory or via a persisted backlog.	`service/matching` · diagram · GitHub `service/matching/configs` · diagram · GitHub `api/matchingservice/v1` · diagram · GitHub	docs · glossary
Memo	Non-indexed user metadata on an execution, returned by describe and list.	`service/history/workflow` · diagram · GitHub `common/persistence/visibility` · diagram · GitHub	docs · glossary
Message protocol (Update)	The worker-to-server message protocol carrying Update requests and responses alongside Workflow Tasks.	`common/protocol` · diagram · GitHub `service/history/workflow/update` · diagram · GitHub	docs · glossary
Multi-Cluster Replication	Async replication of executions to passive clusters over per-shard streams, with version-history conflict resolution.	`service/history/replication` · diagram · GitHub `service/history/replication/eventhandler` · diagram · GitHub `service/history/ndc` · diagram · GitHub `service/history/api/replication` · diagram · GitHub `service/worker/replicator` · diagram · GitHub `common/cluster` · diagram · GitHub `api/replication/v1` · diagram · GitHub	docs · glossary
Mutable state	The materialized per-execution state record held in the executions row and cached on the owning History host.	`service/history/workflow` · diagram · GitHub `service/history/workflow/cache` · diagram · GitHub `service/history/interfaces` · diagram · GitHub `service/history/api/describemutablestate` · diagram · GitHub `api/persistence/v1` · diagram · GitHub	docs · glossary
Namespace	The unit of isolation that scopes workflow IDs, task queues, retention, search attributes, and replication.	`common/namespace` · diagram · GitHub `common/namespace/nsregistry` · diagram · GitHub `common/namespace/nsmanager` · diagram · GitHub `service/frontend` · diagram · GitHub `api/namespace/v1` · diagram · GitHub	docs · glossary
Nexus Async Completion Callback	The HTTP callback a handler posts to when an async operation finishes, routed to the caller's History.	`service/frontend` · diagram · GitHub `service/history/hsm/callbacks` · diagram · GitHub `chasm/lib/callback` · diagram · GitHub `common/callbacks` · diagram · GitHub	docs · glossary
Nexus Endpoint	A named reverse proxy routing a Nexus Service to a namespace and task queue or an external URL.	`common/nexus` · diagram · GitHub `service/frontend` · diagram · GitHub `common/persistence` · diagram · GitHub	docs · glossary
Nexus Machinery	At-least-once delivery of operation start, cancel, and completion across namespace boundaries.	`service/history/queues` · diagram · GitHub `service/frontend` · diagram · GitHub `service/matching` · diagram · GitHub `common/nexus` · diagram · GitHub	docs · glossary
Nexus Operation	One operation on a Nexus Service; the caller side is a state machine (HSM today, CHASM behind a flag) driven by the outbound queue.	`service/history/hsm/nexusoperations` · diagram · GitHub `service/history/hsm/nexusoperations/workflow` · diagram · GitHub `chasm/lib/nexusoperation` · diagram · GitHub `service/history/queues` · diagram · GitHub	docs · glossary
Nexus Operation Handler / Nexus Service	Worker code implementing operations; dispatched from Frontend through Matching to a polling worker.	`service/frontend` · diagram · GitHub `service/matching` · diagram · GitHub `sdk` · SDK repositories	docs · glossary
Nexus Registry	The cluster-wide endpoint store, owned by one Matching node and polled by others.	`common/nexus` · diagram · GitHub `service/matching` · diagram · GitHub `common/persistence` · diagram · GitHub	docs · glossary
Nexus RPC	The open protocol for arbitrary-duration operations with sync and async completion.	`common/nexus/nexusrpc` · diagram · GitHub `common/nexus` · diagram · GitHub	docs · glossary
Nexus Standalone Activity	An operation backed by a Standalone Activity.	`chasm/lib/activity` · diagram · GitHub `chasm/lib/nexusoperation` · diagram · GitHub	docs · glossary
Parent Close Policy	What happens to children when the parent closes: terminate, cancel, or abandon.	`service/worker/parentclosepolicy` · diagram · GitHub `service/history/queues` · diagram · GitHub	docs · glossary
Patching	SDK markers in history so new code can branch on whether an old execution passed a change point.	`sdk` · SDK repositories `service/history/workflow` · diagram · GitHub	docs · glossary
Payload / Payload Converter / Payload Codec / Data Converter	The wire representation of values and the SDK-side serialization and encoding pipeline.	`sdk` · SDK repositories `common/payload` · diagram · GitHub `common/payloads` · diagram · GitHub `common/codec` · diagram · GitHub `api/common/v1` · diagram · GitHub	docs · glossary
Persistence store	The pluggable database (Cassandra, MySQL, Postgres, SQLite) that is the source of truth for shards, executions, history, tasks, and metadata.	`common/persistence` · diagram · GitHub `common/persistence/client` · diagram · GitHub `common/persistence/serialization` · diagram · GitHub `common/persistence/cassandra` · diagram · GitHub `common/persistence/sql` · diagram · GitHub `common/persistence/sql/sqlplugin` · diagram · GitHub `common/persistence/schema` · diagram · GitHub `api/persistence/v1` · diagram · GitHub	docs · glossary
Query	A synchronous read answered by a worker from cached state; dispatched through the sticky queue or attached to the next Workflow Task.	`service/history/api/queryworkflow` · diagram · GitHub `service/history/workflow` · diagram · GitHub `service/matching` · diagram · GitHub	docs · glossary
Queue processor	The per-shard loop that reads a task category from its ack level, schedules, retries, and dead-letters tasks.	`service/history/queues` · diagram · GitHub `service/history/queues/common` · diagram · GitHub `common/tasks` · diagram · GitHub `service/history/api/listqueues` · diagram · GitHub `service/history/api/getdlqtasks` · diagram · GitHub	docs · glossary
RangeID	The per-shard fencing token: a host claims a shard by compare-and-swapping it and every write carries it.	`service/history/shard` · diagram · GitHub `common/persistence` · diagram · GitHub `common/persistence/cassandra` · diagram · GitHub `common/persistence/sql` · diagram · GitHub	docs · glossary
Replication Lag	The delay between active and standby clusters, tracked by the replication streams.	`service/history/replication` · diagram · GitHub	docs · glossary
Requests Per Second (RPS)	Service-level and namespace-level rate limits applied in Frontend interceptors and persistence clients.	`common/quotas` · diagram · GitHub `common/quotas/calculator` · diagram · GitHub `common/rpc/interceptor` · diagram · GitHub `service/frontend` · diagram · GitHub	docs · glossary
Reset	Terminates an execution and starts a new run from a chosen history point by forking a history branch.	`service/history/api/resetworkflow` · diagram · GitHub `service/history/ndc` · diagram · GitHub `service/history/api/reapplyevents` · diagram · GitHub	docs · glossary
Retention Period	How long a closed execution's history stays in persistence before a cleanup timer deletes it.	`service/history/deletemanager` · diagram · GitHub `service/history/queues` · diagram · GitHub `service/history/workflow` · diagram · GitHub	docs · glossary
Retry Policy	Server-side retry attributes for Activities and Workflows; activity retries go straight back to Matching via a retry timer.	`common/retrypolicy` · diagram · GitHub `common/backoff` · diagram · GitHub `service/history/workflow` · diagram · GitHub `service/history/queues` · diagram · GitHub	docs · glossary
Ringpop	Gossip membership plus a consistent hash ring per service, used to find which host owns a shard or partition.	`common/membership` · diagram · GitHub `common/membership/ringpop` · diagram · GitHub `common/membership/static` · diagram · GitHub	docs · glossary
Run ID	A platform-generated ID for one run of a Workflow ID; new runs come from continue-as-new, retry, cron, and reset.	`service/history/api/startworkflow` · diagram · GitHub `service/history/workflow` · diagram · GitHub	docs · glossary
Schedule	A first-class resource that starts executions on a spec, with pause, backfill, and overlap policies; V1 is a system workflow, V2 is CHASM.	`service/worker/scheduler` · diagram · GitHub `chasm/lib/scheduler` · diagram · GitHub `service/worker/scanner/scheduleinvariants` · diagram · GitHub `api/schedule/v1` · diagram · GitHub	docs · glossary
Search Attribute	An indexed key usable in List Filters, set at start or upserted from workflow code.	`common/searchattribute` · diagram · GitHub `common/searchattribute/sadefs` · diagram · GitHub `service/worker/addsearchattributes` · diagram · GitHub `service/frontend` · diagram · GitHub `cmd/tools/gensearchattributehelpers` · diagram · GitHub	docs · glossary
Shard controller	Watches cluster membership and acquires or releases the shards a History host should own.	`service/history/shard` · diagram · GitHub	docs · glossary
Side Effect	A short non-deterministic snippet whose result is recorded as a marker Event.	`sdk` · SDK repositories `service/history/workflow` · diagram · GitHub	docs · glossary
Signal	An asynchronous message to a running execution, written as an Event and triggering a Workflow Task.	`service/history/api/signalworkflow` · diagram · GitHub `service/history/queues` · diagram · GitHub `service/history/api/removesignalmutablestate` · diagram · GitHub	docs · glossary
Signal-With-Start	Atomically start an execution if absent, then deliver a Signal.	`service/history/api/signalwithstartworkflow` · diagram · GitHub `service/history/api/multioperation` · diagram · GitHub	docs · glossary
Speculative Workflow Task	A Workflow Task that is never persisted, so a rejected Update costs zero writes; its timeout runs on an in-memory queue.	`service/history/workflow` · diagram · GitHub `service/history/queues` · diagram · GitHub	docs · glossary
Standalone Activity	An Activity started directly from a client with no enclosing workflow, implemented as a CHASM archetype.	`chasm/lib/activity` · diagram · GitHub `chasm/lib/activity/model` · diagram · GitHub `service/frontend` · diagram · GitHub	docs · glossary
State Transition	One unit of progress of an execution, counted in the transition history that acts as a logical clock.	`service/history/workflow` · diagram · GitHub `common/persistence/transitionhistory` · diagram · GitHub	docs · glossary
Sticky Execution	Routing follow-up Workflow Tasks to a worker-private queue so cached state is reused instead of replayed.	`service/matching` · diagram · GitHub `service/history/api/resetstickytaskqueue` · diagram · GitHub `common/tqid` · diagram · GitHub `sdk` · SDK repositories	docs · glossary
Sync match	Matching handing a task directly to a parked long-poller without writing the backlog.	`service/matching` · diagram · GitHub	docs · glossary
System workflows	Temporal workflows the Worker service runs against the server itself.	`service/worker/scanner` · diagram · GitHub `service/worker/batcher` · diagram · GitHub `service/worker/deletenamespace` · diagram · GitHub `service/worker/parentclosepolicy` · diagram · GitHub `service/worker/addsearchattributes` · diagram · GitHub `common/sdk` · diagram · GitHub	docs · glossary
Tag	A key-value label on an emitted metric.	`common/metrics` · diagram · GitHub `common/log/tag` · diagram · GitHub `api/metrics/v1` · diagram · GitHub	docs · glossary
Task Queue	A dynamically created FIFO queue workers poll; the routing key between server and workers.	`service/matching` · diagram · GitHub `common/tqid` · diagram · GitHub `common/taskqueue` · diagram · GitHub `common/persistence` · diagram · GitHub `api/taskqueue/v1` · diagram · GitHub	docs · glossary
Task queue partition	One of N physical sub-queues of a Task Queue, arranged as a tree with forwarding to the root; load balanced by the Matching client.	`service/matching` · diagram · GitHub `client/matching` · diagram · GitHub `common/tqid` · diagram · GitHub	docs · glossary
Task Routing	Using distinct Task Queues to send specific Activities to specific workers.	`service/matching` · diagram · GitHub `sdk` · SDK repositories	docs · glossary
Task Token	An opaque identifier for one Activity Task Execution used for async completion and heartbeats.	`common/tasktoken` · diagram · GitHub `api/token/v1` · diagram · GitHub	docs · glossary
Temporal CLI / tctl	The user CLI lives in a separate repository; tdbg is the in-repo admin debugging tool.	`cmd/tools/tdbg` · diagram · GitHub `api/cli/v1` · diagram · GitHub	docs · glossary
Temporal Cron Job	Legacy cron by chaining runs under one Workflow ID with a backoff timer between them.	`service/history/workflow` · diagram · GitHub `service/history/queues` · diagram · GitHub	docs · glossary
Temporal SDK / Core SDK / Temporal Client	Language libraries providing the Client and Worker, with a shared Rust core for several languages.	`sdk` · SDK repositories `common/sdk` · diagram · GitHub	docs · glossary
Temporal Server	The four horizontally scalable services (Frontend, History, Matching, Worker) composed with Uber fx and started from one binary.	`temporal` · diagram · GitHub `cmd/server` · diagram · GitHub	docs · glossary
Temporal Service configuration	The static YAML configuration for persistence, services, membership, TLS, and archival.	`common/config` · diagram · GitHub `temporal` · diagram · GitHub `temporal/environment` · diagram · GitHub	docs · glossary
Timer	Durable workflow time APIs; the server fires user timers from the per-shard timer queue even with no worker running.	`service/history/queues` · diagram · GitHub `service/history/workflow` · diagram · GitHub `common/timer` · diagram · GitHub	docs · glossary
Transfer / timer / visibility / outbound / replication tasks	Task categories written in the same transaction as mutable state and executed by per-shard queue processors.	`service/history/tasks` · diagram · GitHub `service/history/queues` · diagram · GitHub `service/history/workflow` · diagram · GitHub	docs · glossary
Transient Workflow Task	A retried Workflow Task whose scheduled and started events are withheld until completion.	`service/history/workflow` · diagram · GitHub	docs · glossary
Update	A synchronous request-and-response that may mutate state, with validation, accepted, and completed phases.	`service/history/workflow/update` · diagram · GitHub `service/history/api/updateworkflow` · diagram · GitHub `service/history/api/pollupdate` · diagram · GitHub `common/protocol` · diagram · GitHub	docs · glossary
Versioned transition	The (failover version, transition count) logical clock for mutable state and CHASM.	`common/persistence/transitionhistory` · diagram · GitHub `chasm` · diagram · GitHub `service/history/workflow` · diagram · GitHub	docs · glossary
Visibility	Listing, counting, and searching executions through an eventually consistent store written by the visibility queue.	`common/persistence/visibility` · diagram · GitHub `common/persistence/visibility/manager` · diagram · GitHub `common/persistence/visibility/store` · diagram · GitHub `common/persistence/visibility/store/elasticsearch` · diagram · GitHub `common/persistence/visibility/store/sql` · diagram · GitHub `service/history/queues` · diagram · GitHub `api/visibilityservice/v1` · diagram · GitHub	docs · glossary
Worker / Worker Process / Worker Entity / Worker Program	The user-run process that polls Task Queues, executes code, and responds to the server.	`sdk` · SDK repositories `service/matching/workers` · diagram · GitHub `common/workercommands` · diagram · GitHub	docs · glossary
Worker Service	Runs system workflows and background jobs (scanner, batcher, schedules V1, worker deployments, migrations) against the Frontend.	`service/worker` · diagram · GitHub `service/worker/scanner` · diagram · GitHub `service/worker/batcher` · diagram · GitHub `service/worker/migration` · diagram · GitHub `service/worker/dlq` · diagram · GitHub	docs · glossary
Worker Session	Go SDK feature running a sequence of Activities on one worker via a host-specific Task Queue.	`sdk` · SDK repositories	docs · glossary
Worker Versioning / Worker Deployment / Build ID	Routing Workflow Tasks only to workers running compatible code; PINNED keeps an execution on its starting version.	`service/matching` · diagram · GitHub `service/worker/workerdeployment` · diagram · GitHub `common/worker_versioning` · diagram · GitHub `service/worker/scanner/build_ids` · diagram · GitHub `api/deployment/v1` · diagram · GitHub	docs · glossary
Workflow cache	The worker-side cache of executions backing Sticky Execution.	`sdk` · SDK repositories	docs · glossary
Workflow Definition	Deterministic user code that defines a workflow; replayed by the SDK against history.	`sdk` · SDK repositories	docs · glossary
Workflow Execution	One durable run of a Workflow Definition, identified by Workflow ID plus Run ID, with its own Event History.	`service/history/workflow` · diagram · GitHub `service/history/api/startworkflow` · diagram · GitHub `service/history/api/describeworkflow` · diagram · GitHub `service/history/api/terminateworkflow` · diagram · GitHub	docs · glossary
Workflow Execution Timeout	Max total time for a Workflow ID across all runs.	`service/history/queues` · diagram · GitHub `service/history/workflow` · diagram · GitHub	docs · glossary
Workflow ID	A user-chosen identifier; at most one open execution per ID per namespace, enforced through the current-execution record.	`service/history/api/startworkflow` · diagram · GitHub `common/persistence` · diagram · GitHub	docs · glossary
Workflow ID Conflict Policy	What to do when starting a Workflow ID that is currently running: fail, use existing, or terminate existing.	`service/history/api/startworkflow` · diagram · GitHub `service/history/api/multioperation` · diagram · GitHub	docs · glossary
Workflow ID Reuse Policy	Whether a new execution may reuse a Workflow ID from a closed execution.	`service/history/api/startworkflow` · diagram · GitHub	docs · glossary
Workflow Run Timeout	Max time for one run.	`service/history/queues` · diagram · GitHub `service/history/workflow` · diagram · GitHub	docs · glossary
Workflow Task	A task telling a worker to advance an execution; History schedules it, Matching dispatches it, the worker replays and returns Commands.	`service/history/workflow` · diagram · GitHub `service/history/api/scheduleworkflowtask` · diagram · GitHub `service/history/api/recordworkflowtaskstarted` · diagram · GitHub `service/history/api/respondworkflowtaskcompleted` · diagram · GitHub `service/history/api/respondworkflowtaskfailed` · diagram · GitHub `service/matching` · diagram · GitHub	docs · glossary
Workflow Task Timeout	How long the server waits for a worker to start a Workflow Task before rescheduling it.	`service/history/queues` · diagram · GitHub `service/history/workflow` · diagram · GitHub	docs · glossary