diff --git a/osbase/event/etcd/etcd.go b/osbase/event/etcd/etcd.go
new file mode 100644
index 0000000..8cf2440
--- /dev/null
+++ b/osbase/event/etcd/etcd.go
@@ -0,0 +1,444 @@
+package etcd
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"sync"
+
+	"github.com/cenkalti/backoff/v4"
+	clientv3 "go.etcd.io/etcd/client/v3"
+
+	"source.monogon.dev/osbase/event"
+)
+
+var (
+	// Type assert that *Value implements event.ValueWatcher. We do this
+	// artificially, as there currently is no code path that needs this to be
+	// strictly true.  However, users of this library might want to rely on the
+	// Value type instead of particular Value implementations.
+	_ event.ValueWatch[StringAt] = &Value[StringAt]{}
+)
+
+// ThinClient is a small wrapper interface to combine
+// clientv3.KV and clientv3.Watcher.
+type ThinClient interface {
+	clientv3.KV
+	clientv3.Watcher
+}
+
+// Value is an 'Event Value' backed in an etcd cluster, accessed over an
+// etcd client. This is a stateless handle and can be copied and shared across
+// goroutines.
+type Value[T any] struct {
+	decoder func(key, value []byte) (T, error)
+	etcd    ThinClient
+	key     string
+	keyEnd  string
+}
+
+type Option struct {
+	rangeEnd string
+}
+
+// Range creates a Value that is backed a range of etcd key/value pairs from
+// 'key' passed to NewValue to 'end' passed to Range.
+//
+// The key range semantics (ie. lexicographic ordering) are the same as in etcd
+// ranges, so for example to retrieve all keys prefixed by `foo/` key should be
+// `foo/` and end should be `foo0`.
+//
+// For any update in the given range, the decoder will be called and its result
+// will trigger the return of a Get() call. The decoder should return a type
+// that lets the user distinguish which of the multiple objects in the range got
+// updated, as the Get() call returns no additional information about the
+// location of the retrieved object by itself.
+//
+// The order of values retrieved by Get() is currently fully arbitrary and must
+// not be relied on. It's possible that in the future the order of updates and
+// the blocking behaviour of Get will be formalized, but this is not yet the
+// case. Instead, the data returned should be treated as eventually consistent
+// with the etcd state.
+//
+// For some uses, it might be necessary to first retrieve all the objects
+// contained within the range before starting to block on updates - in this
+// case, the BacklogOnly option should be used when calling Get.
+func Range(end string) *Option {
+	return &Option{
+		rangeEnd: end,
+	}
+}
+
+// NewValue creates a new Value for a given key(s) in an etcd client. The
+// given decoder will be used to convert bytes retrieved from etcd into the
+// interface{} value retrieved by Get by this value's watcher.
+func NewValue[T any](etcd ThinClient, key string, decoder func(key, value []byte) (T, error), options ...*Option) *Value[T] {
+	res := &Value[T]{
+		decoder: decoder,
+		etcd:    etcd,
+		key:     key,
+		keyEnd:  key,
+	}
+
+	for _, opt := range options {
+		if end := opt.rangeEnd; end != "" {
+			res.keyEnd = end
+		}
+	}
+
+	return res
+}
+
+func DecoderNoop(_, value []byte) ([]byte, error) {
+	return value, nil
+}
+
+func DecoderStringAt(key, value []byte) (StringAt, error) {
+	return StringAt{
+		Key:   string(key),
+		Value: string(value),
+	}, nil
+}
+
+type StringAt struct {
+	Key   string
+	Value string
+}
+
+func (e *Value[T]) Watch() event.Watcher[T] {
+	ctx, ctxC := context.WithCancel(context.Background())
+	return &watcher[T]{
+		Value: *e,
+
+		ctx:  ctx,
+		ctxC: ctxC,
+
+		current: make(map[string][]byte),
+
+		getSem: make(chan struct{}, 1),
+	}
+}
+
+type watcher[T any] struct {
+	// Value copy, used to configure the behaviour of this watcher.
+	Value[T]
+
+	// ctx is the context that expresses the liveness of this watcher. It is
+	// canceled when the watcher is closed, and the etcd Watch hangs off of it.
+	ctx  context.Context
+	ctxC context.CancelFunc
+
+	// getSem is a semaphore used to limit concurrent Get calls and throw an
+	// error if concurrent access is attempted.
+	getSem chan struct{}
+
+	// backlogged is a list of keys retrieved from etcd but not yet returned via
+	// Get. These items are not a replay of all the updates from etcd, but are
+	// already compacted to deduplicate updates to the same object (ie., if the
+	// update stream from etcd is for keys A, B, and A, the backlogged list will
+	// only contain one update for A and B each, with the first update for A being
+	// discarded upon arrival of the second update).
+	//
+	// The keys are an index into the current map, which contains the values
+	// retrieved, including ones that have already been returned via Get. This
+	// persistence allows us to deduplicate spurious updates to the user, in which
+	// etcd returned a new revision of a key, but the data stayed the same.
+	backlogged [][]byte
+	// current map, keyed from etcd key into etcd value at said key. This map
+	// persists alongside an etcd connection, permitting deduplication of spurious
+	// etcd updates even across multiple Get calls.
+	current map[string][]byte
+
+	// prev is the etcd store revision of a previously completed etcd Get/Watch
+	// call, used to resume a Watch call in case of failures.
+	prev *int64
+	// wc is the etcd watch channel, or nil if no channel is yet open.
+	wc clientv3.WatchChan
+
+	// testRaceWG is an optional WaitGroup that, if set, will be waited upon
+	// after the initial KV value retrieval, but before the watch is created.
+	// This is only used for testing.
+	testRaceWG *sync.WaitGroup
+	// testSetupWG is an optional WaitGroup that, if set, will be waited upon
+	// after the etcd watch is created.
+	// This is only used for testing.
+	testSetupWG *sync.WaitGroup
+}
+
+// setup initiates wc (the watch channel from etcd) after retrieving the initial
+// value(s) with a get operation.
+func (w *watcher[T]) setup(ctx context.Context) error {
+	if w.wc != nil {
+		return nil
+	}
+	ranged := w.key != w.keyEnd
+
+	// First, check if some data under this key/range already exists.
+
+	// We use an exponential backoff and retry here as the initial Get can fail
+	// if the cluster is unstable (eg. failing over). We only fail the retry if
+	// the context expires.
+	bo := backoff.NewExponentialBackOff()
+	bo.MaxElapsedTime = 0
+
+	err := backoff.Retry(func() error {
+
+		var getOpts []clientv3.OpOption
+		if ranged {
+			getOpts = append(getOpts, clientv3.WithRange(w.keyEnd))
+		}
+		get, err := w.etcd.Get(ctx, w.key, getOpts...)
+		if err != nil {
+			return fmt.Errorf("when retrieving initial value: %w", err)
+		}
+
+		// Assert that the etcd API is behaving as expected.
+		if !ranged && len(get.Kvs) > 1 {
+			panic("More than one key returned in unary GET response")
+		}
+
+		// After a successful Get, save the revision to watch from and re-build the
+		// backlog from scratch based on what was available in the etcd store at that
+		// time.
+		w.prev = &get.Header.Revision
+
+		w.backlogged = nil
+		w.current = make(map[string][]byte)
+		for _, kv := range get.Kvs {
+			w.backlogged = append(w.backlogged, kv.Key)
+			w.current[string(kv.Key)] = kv.Value
+		}
+		return nil
+
+	}, backoff.WithContext(bo, ctx))
+
+	if w.testRaceWG != nil {
+		w.testRaceWG.Wait()
+	}
+	if err != nil {
+		return err
+	}
+
+	watchOpts := []clientv3.OpOption{
+		clientv3.WithRev(*w.prev + 1),
+	}
+	if ranged {
+		watchOpts = append(watchOpts, clientv3.WithRange(w.keyEnd))
+	}
+	w.wc = w.etcd.Watch(w.ctx, w.key, watchOpts...)
+
+	if w.testSetupWG != nil {
+		w.testSetupWG.Wait()
+	}
+	return nil
+}
+
+// backfill blocks until a backlog of items is available. An error is returned
+// if the context is canceled.
+func (w *watcher[T]) backfill(ctx context.Context) error {
+	// Keep watching for watch events.
+	for {
+		var resp *clientv3.WatchResponse
+		select {
+		case r := <-w.wc:
+			resp = &r
+		case <-ctx.Done():
+			return ctx.Err()
+		}
+
+		if resp.Canceled {
+			// Only allow for watches to be canceled due to context
+			// cancellations. Any other error is something we need to handle,
+			// eg. a client close or compaction error.
+			if errors.Is(resp.Err(), ctx.Err()) {
+				return fmt.Errorf("watch canceled: %w", resp.Err())
+			}
+
+			// Attempt to reconnect.
+			if w.wc != nil {
+				// If a wc already exists, close it. This forces a reconnection
+				// by the next setup call.
+				w.ctxC()
+				w.ctx, w.ctxC = context.WithCancel(context.Background())
+				w.wc = nil
+			}
+			if err := w.setup(ctx); err != nil {
+				return fmt.Errorf("failed to setup watcher: %w", err)
+			}
+			continue
+		}
+
+		w.prev = &resp.Header.Revision
+		// Spurious watch event with no update? Keep trying.
+		if len(resp.Events) == 0 {
+			continue
+		}
+
+		// Process updates into compacted list, transforming deletions into value: nil
+		// keyValues. This maps an etcd key into a pointer in the already existing
+		// backlog list. It will then be used to compact all updates into the smallest
+		// backlog possible (by overriding previously backlogged items for a key if this
+		// key is encountered again).
+		//
+		// TODO(q3k): this could be stored in the watcher state to not waste time on
+		// each update, but it's good enough for now.
+
+		// Prepare a set of keys that already exist in the backlog. This will be used
+		// to make sure we don't duplicate backlog entries while maintaining a stable
+		// backlog order.
+		seen := make(map[string]bool)
+		for _, k := range w.backlogged {
+			seen[string(k)] = true
+		}
+
+		for _, ev := range resp.Events {
+			var value []byte
+			switch ev.Type {
+			case clientv3.EventTypeDelete:
+			case clientv3.EventTypePut:
+				value = ev.Kv.Value
+			default:
+				return fmt.Errorf("invalid event type %v", ev.Type)
+			}
+
+			keyS := string(ev.Kv.Key)
+			prev := w.current[keyS]
+			// Short-circuit and skip updates with the same content as already present.
+			// These are sometimes emitted by etcd.
+			if bytes.Equal(prev, value) {
+				continue
+			}
+
+			// Only insert to backlog if not yet present, but maintain order.
+			if !seen[string(ev.Kv.Key)] {
+				w.backlogged = append(w.backlogged, ev.Kv.Key)
+				seen[string(ev.Kv.Key)] = true
+			}
+			// Regardless of backlog list, always update the key to its newest value.
+			w.current[keyS] = value
+		}
+
+		// Still nothing in backlog? Keep trying.
+		if len(w.backlogged) == 0 {
+			continue
+		}
+
+		return nil
+	}
+}
+
+type GetOption struct {
+	backlogOnly bool
+}
+
+// Get implements the Get method of the Watcher interface.
+// It can return an error in three cases:
+//   - the given context is canceled (in which case, the given error will wrap
+//     the context error)
+//   - the watcher's BytesDecoder returned an error (in which case the error
+//     returned by the BytesDecoder will be returned verbatim)
+//   - it has been called with BacklogOnly and the Watcher has no more local
+//     event data to return (see BacklogOnly for more information on the
+//     semantics of this mode of operation)
+//
+// Note that transient and permanent etcd errors are never returned, and the
+// Get call will attempt to recover from these errors as much as possible. This
+// also means that the user of the Watcher will not be notified if the
+// underlying etcd client disconnects from the cluster, or if the cluster loses
+// quorum.
+//
+// TODO(q3k): implement leases to allow clients to be notified when there are
+// transient cluster/quorum/partition errors, if needed.
+//
+// TODO(q3k): implement internal, limited buffering for backlogged data not yet
+// consumed by client, as etcd client library seems to use an unbound buffer in
+// case this happens ( see: watcherStream.buf in clientv3).
+func (w *watcher[T]) Get(ctx context.Context, opts ...event.GetOption[T]) (T, error) {
+	var empty T
+	select {
+	case w.getSem <- struct{}{}:
+	default:
+		return empty, fmt.Errorf("cannot Get() concurrently on a single waiter")
+	}
+	defer func() {
+		<-w.getSem
+	}()
+
+	backlogOnly := false
+	var predicate func(t T) bool
+	for _, opt := range opts {
+		if opt.Predicate != nil {
+			predicate = opt.Predicate
+		}
+		if opt.BacklogOnly {
+			backlogOnly = true
+		}
+	}
+
+	ranged := w.key != w.keyEnd
+	if ranged && predicate != nil {
+		return empty, errors.New("filtering unimplemented for ranged etcd values")
+	}
+	if backlogOnly && predicate != nil {
+		return empty, errors.New("filtering unimplemented for backlog-only requests")
+	}
+
+	for {
+		v, err := w.getUnlocked(ctx, ranged, backlogOnly)
+		if err != nil {
+			return empty, err
+		}
+		if predicate == nil || predicate(v) {
+			return v, nil
+		}
+	}
+}
+
+func (w *watcher[T]) getUnlocked(ctx context.Context, ranged, backlogOnly bool) (T, error) {
+	var empty T
+	// Early check for context cancelations, preventing spurious contact with etcd
+	// if there's no need to.
+	if w.ctx.Err() != nil {
+		return empty, w.ctx.Err()
+	}
+
+	if err := w.setup(ctx); err != nil {
+		return empty, fmt.Errorf("when setting up watcher: %w", err)
+	}
+
+	if backlogOnly && len(w.backlogged) == 0 {
+		return empty, event.ErrBacklogDone
+	}
+
+	// Update backlog from etcd if needed.
+	if len(w.backlogged) < 1 {
+		err := w.backfill(ctx)
+		if err != nil {
+			return empty, fmt.Errorf("when watching for new value: %w", err)
+		}
+	}
+	// Backlog is now guaranteed to contain at least one element.
+
+	if !ranged {
+		// For non-ranged queries, drain backlog fully.
+		if len(w.backlogged) != 1 {
+			panic(fmt.Sprintf("multiple keys in nonranged value: %v", w.backlogged))
+		}
+		k := w.backlogged[0]
+		v := w.current[string(k)]
+		w.backlogged = nil
+		return w.decoder(k, v)
+	} else {
+		// For ranged queries, pop one ranged query off the backlog.
+		k := w.backlogged[0]
+		v := w.current[string(k)]
+		w.backlogged = w.backlogged[1:]
+		return w.decoder(k, v)
+	}
+}
+
+func (w *watcher[T]) Close() error {
+	w.ctxC()
+	return nil
+}