diff --git a/protobuf/agent.proto b/protobuf/agent.proto
new file mode 100644
index 00000000..c1ad2152
--- /dev/null
+++ b/protobuf/agent.proto
@@ -0,0 +1,22 @@
+// Copyright (c) 2017 Uber Technologies, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax = "proto3";
+package jaegertracing.protobuf.agent;
+
+import "jaeger.proto";
+
+service Agent {
+    rpc EmitBatch(stream Batch) returns (Empty);
+}
diff --git a/protobuf/baggage.proto b/protobuf/baggage.proto
new file mode 100644
index 00000000..1bd5eb58
--- /dev/null
+++ b/protobuf/baggage.proto
@@ -0,0 +1,32 @@
+// Copyright (c) 2017 Uber Technologies, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax = "proto3";
+package jaegertracing.protobuf.baggage;
+
+import "jaeger.proto";
+
+message BaggageRestriction {
+    string baggage_key = 1;
+    int32 max_value_length = 2;
+}
+
+message BaggageRestrictionResponse {
+    repeated BaggageRestriction restrictions = 1;
+}
+
+service BaggageRestrictionManager {
+    rpc GetBaggageRestrictions (ServiceRequest) returns
+        (BaggageRestrictionResponse);
+}
diff --git a/protobuf/crossdock/tracetest.proto b/protobuf/crossdock/tracetest.proto
new file mode 100644
index 00000000..ad7bd83e
--- /dev/null
+++ b/protobuf/crossdock/tracetest.proto
@@ -0,0 +1,62 @@
+// Copyright (c) 2017 Uber Technologies, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax = "proto3";
+package jaegertracing.protobuf.crossdock;
+
+enum Transport {
+    HTTP = 0;
+    TCHANNEL = 1;
+    DUMMY = 2;
+}
+
+message Downstream {
+    string service_name = 1;
+    string server_role = 2;
+    string host = 3;
+    string port = 4;
+    Transport transport = 5;
+}
+
+message StartTraceRequest {
+    string server_role = 1;
+    bool sampled = 2;
+    string baggage = 3;
+    repeated Downstream downstream = 4;
+}
+
+message JoinTraceRequest {
+    string server_role = 1;
+    repeated Downstream downstream = 2;
+}
+
+message ObservedSpan {
+    string trace_id = 1;
+    bool sampled = 2;
+    string baggage = 3;
+}
+
+message DownstreamResponse {
+    ObservedSpan observed_span = 1;
+    string not_implemented_error = 2;
+}
+
+message TraceResponse {
+    repeated DownstreamResponse responses = 1;
+}
+
+service TracedService {
+    rpc StartTrace (StartTraceRequest) returns (TraceResponse);
+    rpc JoinTrace (JoinTraceRequest) returns (TraceResponse);
+}
diff --git a/protobuf/jaeger.proto b/protobuf/jaeger.proto
new file mode 100644
index 00000000..817a369f
--- /dev/null
+++ b/protobuf/jaeger.proto
@@ -0,0 +1,81 @@
+// Copyright (c) 2017 Uber Technologies, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax = "proto3";
+package jaegertracing.protobuf;
+
+message Empty {};
+
+message ServiceRequest {
+    string service_name = 1;
+}
+
+message Tag {
+    string key = 1;
+    oneof value {
+        string str_value = 2;
+        double double_value = 3;
+        bool bool_value = 4;
+        int64 long_value = 5;
+        bytes binary_value = 6;
+    }
+}
+
+message Log {
+    int64 timestamp = 1;
+    repeated Tag fields = 2;
+}
+
+message SpanRef {
+    enum Type {
+        CHILD_OF = 0;
+        FOLLOWS_FROM = 1;
+    }
+    Type type = 1;
+    uint64 trace_id_high = 2;
+    uint64 trace_id_low = 3;
+    uint64 span_id = 4;
+}
+
+message Span {
+    uint64 trace_id_high = 1;
+    uint64 trace_id_low = 2;
+    uint64 span_id = 3;
+    uint64 parent_span_id = 4;
+    string operation_name = 5;
+    repeated SpanRef references = 6;
+    int32 flags = 7;
+    int64 start_time = 8;
+    int64 duration = 9;
+    repeated Tag tags = 10;
+    repeated Log logs = 11;
+}
+
+message Process {
+    string service_name = 1;
+    repeated Tag tags = 2;
+}
+
+message Batch {
+    Process process = 1;
+    repeated Span spans = 2;
+}
+
+message BatchResponse {
+    bool ok = 1;
+};
+
+service Collector {
+    rpc SubmitBatches (stream Batch) returns (stream BatchResponse);
+}
diff --git a/protobuf/sampling.proto b/protobuf/sampling.proto
new file mode 100644
index 00000000..1c411f94
--- /dev/null
+++ b/protobuf/sampling.proto
@@ -0,0 +1,57 @@
+// Copyright (c) 2017 Uber Technologies, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax = "proto3";
+package jaegertracing.protobuf.sampling_manager;
+
+import "jaeger.proto";
+
+message ProbabilisticSamplingStrategy {
+    double sampling_rate = 1;
+}
+
+message RateLimitingSamplingStrategy {
+    int32 max_traces_per_seconds = 1;
+}
+
+message SamplingStrategy {
+    oneof strategy {
+        ProbabilisticSamplingStrategy probabilistic = 1;
+        RateLimitingSamplingStrategy rate_limiting = 2;
+    }
+}
+
+message OperationSamplingStrategy {
+    string operation = 1;
+    SamplingStrategy strategy = 2;
+}
+
+message PerOperationSamplingStrategy {
+    double default_sampling_probability = 1;
+    double default_lower_bound_traces_per_second = 2;
+    repeated OperationSamplingStrategy per_operation_strategy = 3;
+    double default_upper_bound_traces_per_second = 4;
+}
+
+message SamplingStrategyResponse {
+    oneof strategy {
+        ProbabilisticSamplingStrategy probabilistic = 1;
+        RateLimitingSamplingStrategy rate_limiting = 2;
+        PerOperationSamplingStrategy per_operation = 3;
+    }
+}
+
+service SamplingManager {
+    rpc GetSamplingStrategy (ServiceRequest) returns (SamplingStrategyResponse);
+}