diff --git a/packages/echo/program.ts b/packages/echo/program.ts
index 6c5c76df..50602b8c 100644
--- a/packages/echo/program.ts
+++ b/packages/echo/program.ts
@@ -3,13 +3,13 @@ import * as tdl from '@unmango/tdl';
 import * as cmd from './command';
 import { name, version } from './package.json';
 
-const mimeTypeOption = new Option('--type <TYPE>', 'The media type of the input.')
-	.choices(tdl.SUPPORTED_MIME_TYPES);
+const mediaTypeOption = new Option('--type <TYPE>', 'The media type of the input.')
+	.choices(tdl.SUPPORTED_MEDIA_TYPES);
 
 export const from = (program: Command): Command => {
 	program.command('from')
 		.description('Write back the protobuf data.')
-		.addOption(mimeTypeOption)
+		.addOption(mediaTypeOption)
 		.action(async (_) => {
 			const echo = new cmd.Echo();
 			const spec = await echo.from(Bun.stdin);
@@ -22,7 +22,7 @@ export const from = (program: Command): Command => {
 export const gen = (program: Command): Command => {
 	program.command('gen')
 		.description('Also, write back the protobuf data.')
-		.addOption(mimeTypeOption)
+		.addOption(mediaTypeOption)
 		.action(async (_) => {
 			const echo = new cmd.Echo();
 			const spec = await echo.from(Bun.stdin);
diff --git a/packages/tdl/index.ts b/packages/tdl/index.ts
index d2b0c32b..064b9cd0 100644
--- a/packages/tdl/index.ts
+++ b/packages/tdl/index.ts
@@ -1,3 +1,3 @@
-export * from './mime';
+export * from './mediaType';
 export * from './runner';
 export * from './types';
diff --git a/packages/tdl/mime.spec.ts b/packages/tdl/mediaType.spec.ts
similarity index 90%
rename from packages/tdl/mime.spec.ts
rename to packages/tdl/mediaType.spec.ts
index 271fa2f9..f957f52d 100644
--- a/packages/tdl/mime.spec.ts
+++ b/packages/tdl/mediaType.spec.ts
@@ -1,7 +1,7 @@
 import { Spec } from '@unmango/tdl-es';
 import { describe, expect, it } from 'bun:test';
 import fc from 'fast-check';
-import { read, type SupportedMimeType } from './mime';
+import { read, type SupportedMediaType } from './mediaType';
 
 const arbSpec = () =>
 	fc.gen().map(g =>
@@ -15,7 +15,7 @@ const arbSpec = () =>
 	);
 
 describe('read', () => {
-	it.each<SupportedMimeType>([
+	it.each<SupportedMediaType>([
 		'application/protobuf',
 		'application/x-protobuf',
 		'application/vnd.google.protobuf',
diff --git a/packages/tdl/mime.ts b/packages/tdl/mediaType.ts
similarity index 70%
rename from packages/tdl/mime.ts
rename to packages/tdl/mediaType.ts
index 63bcb795..065eb192 100644
--- a/packages/tdl/mime.ts
+++ b/packages/tdl/mediaType.ts
@@ -1,16 +1,16 @@
 import * as tdl from '@unmango/tdl-es';
 
-export const SUPPORTED_MIME_TYPES = [
+export const SUPPORTED_MEDIA_TYPES = [
 	'application/json',
 	'application/x-protobuf',
 	'application/protobuf',
 	'application/vnd.google.protobuf',
 ] as const;
 
-export type SupportedMimeTypeTuple = typeof SUPPORTED_MIME_TYPES;
-export type SupportedMimeType = SupportedMimeTypeTuple[number];
+export type SupportedMediaTypeTuple = typeof SUPPORTED_MEDIA_TYPES;
+export type SupportedMediaType = SupportedMediaTypeTuple[number];
 
-export function read(data: Uint8Array, type?: SupportedMimeType): tdl.Spec {
+export function read(data: Uint8Array, type?: SupportedMediaType): tdl.Spec {
 	switch (type) {
 		case 'application/json': {
 			const decoder = new TextDecoder();
diff --git a/packages/uml2ts/command.spec.ts b/packages/uml2ts/command.spec.ts
index 3e0f5c11..55a84cd4 100644
--- a/packages/uml2ts/command.spec.ts
+++ b/packages/uml2ts/command.spec.ts
@@ -1,4 +1,4 @@
-import type { SupportedMimeType } from '@unmango/tdl';
+import type { SupportedMediaType } from '@unmango/tdl';
 import { Spec } from '@unmango/tdl-es';
 import { afterAll, beforeAll, describe, expect, it } from 'bun:test';
 import fs from 'node:fs/promises';
@@ -32,16 +32,16 @@ beforeAll(async () => {
 afterAll(ensureClean);
 
 describe('gen', () => {
-	it.each<SupportedMimeType>([
+	it.each<SupportedMediaType>([
 		'application/protobuf',
 		'application/x-protobuf',
 		'application/vnd.google.protobuf',
-	])('should read %s data', async (mime) => {
+	])('should read %s data', async (mediaType) => {
 		const name = 'testType';
 		const spec = new Spec({ types: { [name]: {} } });
 		const bytes = spec.toBinary();
 
-		const proc = Bun.spawn([binPath, 'gen', '--type', mime], {
+		const proc = Bun.spawn([binPath, 'gen', '--type', mediaType], {
 			stdin: new Blob([bytes]),
 		});
 
@@ -53,9 +53,9 @@ describe('gen', () => {
 		const name = 'testType';
 		const spec = new Spec({ types: { [name]: {} } });
 		const json = spec.toJsonString();
-		const mime: SupportedMimeType = 'application/json';
+		const media: SupportedMediaType = 'application/json';
 
-		const proc = Bun.spawn([binPath, 'gen', '--type', mime], {
+		const proc = Bun.spawn([binPath, 'gen', '--type', media], {
 			stdin: Buffer.from(json, 'utf-8'),
 		});
 
diff --git a/packages/uml2ts/command.ts b/packages/uml2ts/command.ts
index 864e4043..b695a147 100644
--- a/packages/uml2ts/command.ts
+++ b/packages/uml2ts/command.ts
@@ -2,7 +2,7 @@ import { gen as generate } from '@unmango/2ts';
 import * as tdl from '@unmango/tdl';
 import { ArrayBufferSink } from 'bun';
 
-export async function gen(type?: tdl.SupportedMimeType): Promise<void> {
+export async function gen(type?: tdl.SupportedMediaType): Promise<void> {
 	const buffer = await Bun.stdin.arrayBuffer();
 	const spec = tdl.read(new Uint8Array(buffer), type);
 	const sink = new ArrayBufferSink();
diff --git a/packages/uml2ts/program.ts b/packages/uml2ts/program.ts
index 836119bb..d7aea643 100644
--- a/packages/uml2ts/program.ts
+++ b/packages/uml2ts/program.ts
@@ -3,13 +3,13 @@ import * as tdl from '@unmango/tdl';
 import * as cmd from './command';
 import { name, version } from './package.json';
 
-const mimeTypeOption = new Option('--type <TYPE>', 'The media type of the input.')
-	.choices(tdl.SUPPORTED_MIME_TYPES);
+const mediaTypeOption = new Option('--type <TYPE>', 'The media type of the input.')
+	.choices(tdl.SUPPORTED_MEDIA_TYPES);
 
 export const gen = (program: Command): Command =>
 	program.command('gen')
 		.description('Generate typescript.')
-		.addOption(mimeTypeOption)
+		.addOption(mediaTypeOption)
 		.action((opts) => cmd.gen(opts.type));
 
 export const program = (): Command =>
diff --git a/pkg/go.mod b/pkg/go.mod
index dbb88e07..d7afe91f 100644
--- a/pkg/go.mod
+++ b/pkg/go.mod
@@ -11,6 +11,7 @@ require (
 	github.com/pulumi/pulumi/pkg/v3 v3.121.0
 	github.com/unstoppablemango/tdl/gen v0.0.18
 	google.golang.org/protobuf v1.34.2
+	gopkg.in/yaml.v3 v3.0.1
 )
 
 require (
@@ -125,7 +126,6 @@ require (
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20240515191416-fc5f0ca64291 // indirect
 	google.golang.org/grpc v1.64.0 // indirect
 	gopkg.in/warnings.v0 v0.1.2 // indirect
-	gopkg.in/yaml.v3 v3.0.1 // indirect
 	gotest.tools/v3 v3.5.1 // indirect
 	lukechampine.com/frand v1.4.2 // indirect
 )
diff --git a/pkg/go.sum b/pkg/go.sum
index 1091cc2e..2d996798 100644
--- a/pkg/go.sum
+++ b/pkg/go.sum
@@ -204,12 +204,8 @@ github.com/pulumi/appdash v0.0.0-20231130102222-75f619a67231 h1:vkHw5I/plNdTr435
 github.com/pulumi/appdash v0.0.0-20231130102222-75f619a67231/go.mod h1:murToZ2N9hNJzewjHBgfFdXhZKjY3z5cYC1VXk+lbFE=
 github.com/pulumi/esc v0.9.1 h1:HH5eEv8sgyxSpY5a8yePyqFXzA8cvBvapfH8457+mIs=
 github.com/pulumi/esc v0.9.1/go.mod h1:oEJ6bOsjYlQUpjf70GiX+CXn3VBmpwFDxUTlmtUN84c=
-github.com/pulumi/pulumi/pkg/v3 v3.120.0 h1:L2b8DiI4dQa+iRGXdbrMQl2AXUfnjP3siHEas6xPW84=
-github.com/pulumi/pulumi/pkg/v3 v3.120.0/go.mod h1:ZLTGs4I1q5VXzjV5LLBLVIAfE811TMsSDFJaWs7WD4g=
 github.com/pulumi/pulumi/pkg/v3 v3.121.0 h1:cLUQJYGJKfgCY0ubJo8dVwmsIm2WcgTprb9Orc/yiFg=
 github.com/pulumi/pulumi/pkg/v3 v3.121.0/go.mod h1:aaRixfKOh4DhGtuDJcI56dTPkb7oJBgRgH1aMF1FzbU=
-github.com/pulumi/pulumi/sdk/v3 v3.120.0 h1:KYtMkCmcSg4U+w41/Q0l3llKEodbfdyq6J0VMoEoVmY=
-github.com/pulumi/pulumi/sdk/v3 v3.120.0/go.mod h1:/mQJPO+HehhoSJ9O3C6eUKAGeAr+4KSrbDhLsXHKldc=
 github.com/pulumi/pulumi/sdk/v3 v3.121.0 h1:UsnFKIVOtJN/hQKPkWHL9cZktewPVQRbNUXbXQY/qrk=
 github.com/pulumi/pulumi/sdk/v3 v3.121.0/go.mod h1:p1U24en3zt51agx+WlNboSOV8eLlPWYAkxMzVEXKbnY=
 github.com/rivo/uniseg v0.1.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
diff --git a/pkg/uml/converter.go b/pkg/uml/converter.go
index 38c55d8a..30a8a2af 100644
--- a/pkg/uml/converter.go
+++ b/pkg/uml/converter.go
@@ -6,7 +6,7 @@ import (
 )
 
 type ConverterOptions struct {
-	MimeType *string
+	MediaType *string
 }
 
 type ConverterOption func(*ConverterOptions) error
@@ -19,9 +19,9 @@ type NewConverter[T any] interface {
 	RunnerFactory[T, Converter]
 }
 
-func WithMimeType(t string) ConverterOption {
+func WithMediaType(t string) ConverterOption {
 	return func(opts *ConverterOptions) error {
-		opts.MimeType = &t
+		opts.MediaType = &t
 		return nil
 	}
 }
diff --git a/pkg/uml/marshal.go b/pkg/uml/marshal.go
index 8e726d89..ac14378a 100644
--- a/pkg/uml/marshal.go
+++ b/pkg/uml/marshal.go
@@ -4,26 +4,80 @@ import (
 	"encoding/json"
 	"fmt"
 	"mime"
+	"regexp"
 
 	"google.golang.org/protobuf/proto"
+	"gopkg.in/yaml.v3"
 )
 
-func Unmarshal(v string, b []byte, spec *Spec) error {
-	media, _, err := mime.ParseMediaType(v)
+var (
+	jsonMatcher = regexp.MustCompile(`.*\.json`)
+	yamlMatcher = regexp.MustCompile(`.*\.ya?ml`)
+)
+
+func Marshal(typ string, spec *Spec) ([]byte, error) {
+	mediaType, err := parseMediaType(typ)
+	if err != nil {
+		return nil, err
+	}
+
+	switch mediaType {
+	case "application/json":
+	case "text/json":
+		return json.Marshal(spec)
+	case "application/x-protobuf":
+	case "application/protobuf":
+	case "application/vnd.google.protobuf":
+		return proto.Marshal(spec)
+	case "application/x-yaml":
+	case "application/yaml":
+	case "text/yaml":
+		return yaml.Marshal(spec)
+	}
+
+	return nil, fmt.Errorf("unsupported media type: %s", mediaType)
+}
+
+func Unmarshal(typ string, data []byte, spec *Spec) error {
+	mediaType, err := parseMediaType(typ)
 	if err != nil {
 		return err
 	}
 
-	switch media {
+	switch mediaType {
 	case "application/json":
-		err = json.Unmarshal(b, spec)
+	case "text/json":
+		return json.Unmarshal(data, spec)
 	case "application/x-protobuf":
 	case "application/protobuf":
 	case "application/vnd.google.protobuf":
-		err = proto.Unmarshal(b, spec)
-	default:
-		err = fmt.Errorf("unsupported media type: %s", media)
+		return proto.Unmarshal(data, spec)
+	case "application/x-yaml":
+	case "application/yaml":
+	case "text/yaml":
+		return yaml.Unmarshal(data, spec)
+	}
+
+	return fmt.Errorf("unsupported media type: %s", mediaType)
+}
+
+func GuessMediaType(x string) (string, error) {
+	if x == "stdin" {
+		return "application/protobuf", nil
 	}
 
-	return err
+	if yamlMatcher.MatchString(x) {
+		return "application/yaml", nil
+	}
+
+	if jsonMatcher.MatchString(x) {
+		return "application/json", nil
+	}
+
+	return "", fmt.Errorf("failed to guess media type for: %s", x)
+}
+
+func parseMediaType(x string) (string, error) {
+	mediaType, _, err := mime.ParseMediaType(x)
+	return mediaType, err
 }