diff --git a/.travis.yml b/.travis.yml
index b54e2c3..7d95fab 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,4 +1,16 @@
 language: go
-
+cache:
+  directories:
+    - $GOPATH/pkg
+before_install:
+  - export GOCACHE=$GOPATH/pkg/cache
+install:
+  - go mod download
+script:
+  - go test -v ./...
+  - go vet -v ./...
+env:
+  global:
+    - GO111MODULE=on
 go:
-  - tip
+  - 1.x
diff --git a/compiler/compiler.go b/compiler/compiler.go
index 166ba78..e8da559 100644
--- a/compiler/compiler.go
+++ b/compiler/compiler.go
@@ -1,6 +1,6 @@
 // Package compiler contains tools to take openapi.* definitions and
 // compile them into protobuf.* structures.
-package compiler
+package compiler // github.com/NYTimes/openapi2proto/compiler
 
 import (
 	"bytes"
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..e329919
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,10 @@
+module github.com/NYTimes/openapi2proto
+
+go 1.12
+
+require (
+	github.com/dolmen-go/jsonptr v0.0.0-20190227181151-a830c2c3c0fe
+	github.com/pkg/errors v0.8.1
+	github.com/pmezard/go-difflib v1.0.0
+	gopkg.in/yaml.v2 v2.2.2
+)
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..2bdd8ee
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,9 @@
+github.com/dolmen-go/jsonptr v0.0.0-20190227181151-a830c2c3c0fe h1:7UArST+CxXqtOBr8r+/jF8/jtP9I7CLMjYnLx/GEVH0=
+github.com/dolmen-go/jsonptr v0.0.0-20190227181151-a830c2c3c0fe/go.mod h1:GG6FAkYtUFD/rqS31kfcho/lSCed6Gqm1X0uiIEU0tA=
+github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
+github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
+gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
diff --git a/internal/option/option.go b/internal/option/option.go
index 1dc8236..05328fa 100644
--- a/internal/option/option.go
+++ b/internal/option/option.go
@@ -1,4 +1,4 @@
-package option
+package option // github.com/NYTimes/openapi2proto/internal/option
 
 type Option interface {
 	Name() string
diff --git a/openapi/interface.go b/openapi/interface.go
index 921f4d7..bcf528f 100644
--- a/openapi/interface.go
+++ b/openapi/interface.go
@@ -81,7 +81,7 @@ type Parameter struct {
 	Name        string     `yaml:"name" json:"name"`
 	Description string     `yaml:"description" json:"description"`
 	Enum        []string   `yaml:"enum,omitempty" json:"enum,omitempty"`
-	Format      string     `yaml:"format,omitempty", json:"format,omitempty"`
+	Format      string     `yaml:"format,omitempty" json:"format,omitempty"`
 	In          string     `yaml:"in,omitempty" json:"in,omitempty"`
 	Items       *Schema    `yaml:"items,omitempty" json:"items,omitempty"`
 	ProtoTag    int        `yaml:"x-proto-tag" json:"x-proto-tag"`
diff --git a/openapi/openapi.go b/openapi/openapi.go
index 90cd0e8..6df002e 100644
--- a/openapi/openapi.go
+++ b/openapi/openapi.go
@@ -1,6 +1,6 @@
 // Package openapi contains tools to read in OpenAPI specifications
 // so that they can be passed to the openapi2proto compiler
-package openapi
+package openapi // github.com/NYTimes/openapi2proto/openapi
 
 import (
 	"bytes"
diff --git a/protobuf/protobuf.go b/protobuf/protobuf.go
index 9a780cb..d9ff726 100644
--- a/protobuf/protobuf.go
+++ b/protobuf/protobuf.go
@@ -1,4 +1,4 @@
 // Package protobuf contains structures to represent a protobuf
 // definition, and tools to create textual representation of the
 // definition.
-package protobuf
\ No newline at end of file
+package protobuf // github.com/NYTimes/openapi2proto/protobuf
diff --git a/transpiler.go b/transpiler.go
index 304bbdf..0a77e69 100644
--- a/transpiler.go
+++ b/transpiler.go
@@ -1,4 +1,4 @@
-package openapi2proto
+package openapi2proto // github.com/NYTimes/openapi2proto
 
 import (
 	"io"