diff --git a/pyproject.toml b/pyproject.toml
index 4c28a13..67040ff 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -76,6 +76,21 @@ codelinks = "sphinx_codelinks.cmd:app"
 "docs:rm" = "rm -rf docs/_build/html"
 "docs" = "sphinx-build -nW --keep-going -b html -T -c docs docs/source docs/_build/html"
 "docs:clean" = { chain = ["docs:rm", "docs"] }
+# needextend demo
+"analyse" = "codelinks analyse tests/data/configs/minimum_config.toml"
+"analyse:rm" = "rm -rf output/marked_content.json"
+"write" = "codelinks write rst output/marked_content.json --outpath tests/data/needextend_demo/needextend.rst"
+"write:rm" = "rm -rf tests/data/needextend_demo/needextend.rst"
+"demo:rm" = "rm -rf tests/data/needextend_demo/_build"
+"demo:build" = "sphinx-build -nW --keep-going -b html -T -c tests/data/needextend_demo tests/data/needextend_demo tests/data/needextend_demo/_build/html"
+"demo:clean" = { chain = [
+  "demo:rm",
+  "analyse:rm",
+  "write:rm",
+  "analyse",
+  "write",
+  "demo:build",
+] }
 
 [tool.ruff.lint]
 extend-select = [
diff --git a/src/sphinx_codelinks/analyse/models.py b/src/sphinx_codelinks/analyse/models.py
index 66fb349..856f0a0 100644
--- a/src/sphinx_codelinks/analyse/models.py
+++ b/src/sphinx_codelinks/analyse/models.py
@@ -7,8 +7,8 @@
 
 
 class MarkedContentType(str, Enum):
-    need = ("need",)
-    need_id_refs = ("need-id-refs",)
+    need = "need"
+    need_id_refs = "need-id-refs"
     rst = "rst"
 
 
diff --git a/src/sphinx_codelinks/cmd.py b/src/sphinx_codelinks/cmd.py
index 53dde99..bc0077f 100644
--- a/src/sphinx_codelinks/cmd.py
+++ b/src/sphinx_codelinks/cmd.py
@@ -1,8 +1,9 @@
 from collections import deque
+import json
 from os import linesep
 from pathlib import Path
 import tomllib
-from typing import Annotated, cast
+from typing import Annotated, TypeAlias, cast
 
 import typer
 
@@ -13,6 +14,8 @@
     CodeLinksProjectConfigType,
     generate_project_configs,
 )
+from sphinx_codelinks.logger import logger
+from sphinx_codelinks.needextend_write import MarkedObjType, convert_marked_content
 from sphinx_codelinks.source_discover.config import (
     CommentType,
     SourceDiscoverConfig,
@@ -23,6 +26,33 @@
 app = typer.Typer(
     no_args_is_help=True, context_settings={"help_option_names": ["-h", "--help"]}
 )
+write_app = typer.Typer(
+    help="Export marked content to other formats", no_args_is_help=True
+)
+app.add_typer(write_app, name="write", rich_help_panel="Sub-menus")
+
+OptVerbose: TypeAlias = Annotated[  # noqa: UP040   # has to be TypeAlias
+    bool,
+    typer.Option(
+        ...,
+        "-v",
+        "--verbose",
+        is_flag=True,
+        help="Show debug information",
+        rich_help_panel="Logging",
+    ),
+]
+OptQuiet: TypeAlias = Annotated[  # noqa: UP040 # has to be TypeAlias
+    bool,
+    typer.Option(
+        ...,
+        "-q",
+        "--quiet",
+        is_flag=True,
+        help="Only show errors and warnings",
+        rich_help_panel="Logging",
+    ),
+]
 
 
 @app.command(no_args_is_help=True)
@@ -190,6 +220,79 @@ def discover(
         typer.echo(file_path)
 
 
+@write_app.command("rst", no_args_is_help=True)
+def write_rst(  # noqa: PLR0913  # for CLI, so it takes as many as it requires
+    jsonpath: Annotated[
+        Path,
+        typer.Argument(
+            ...,
+            help="Path of the JSON file which contains the extracted markers",
+            show_default=False,
+            dir_okay=False,
+            file_okay=True,
+            exists=True,
+            resolve_path=True,
+        ),
+    ],
+    outpath: Annotated[
+        Path,
+        typer.Option(
+            "--outpath",
+            "-o",
+            help="The output path for generated rst file",
+            show_default=True,
+            dir_okay=False,
+            file_okay=True,
+            exists=False,
+        ),
+    ] = Path("needextend.rst"),
+    remote_url_field: Annotated[
+        str,
+        typer.Option(
+            "--remote-url-field",
+            "-r",
+            help="The field name for the remote url",
+            show_default=True,
+        ),
+    ] = "remote_url",  # to show default value in this CLI
+    title: Annotated[
+        str | None,
+        typer.Option(
+            "--title",
+            "-t",
+            help="Give the title to the generated RST file",
+            show_default=True,
+        ),
+    ] = None,  # to show default value in this CLI
+    verbose: OptVerbose = False,
+    quiet: OptQuiet = False,
+) -> None:
+    """Generate needextend.rst from the extracted obj in JSON."""
+    logger.configure(verbose, quiet)
+    try:
+        with jsonpath.open("r") as f:
+            marked_content = json.load(f)
+    except Exception as e:
+        raise typer.BadParameter(
+            f"Failed to load marked content from {jsonpath}: {e}"
+        ) from e
+
+    marked_objs: list[MarkedObjType] = [
+        obj for objs in marked_content.values() for obj in objs
+    ]
+
+    needextend_texts, errors = convert_marked_content(
+        marked_objs, remote_url_field, title
+    )
+    if errors:
+        raise typer.BadParameter(
+            f"Errors occurred during conversion: {linesep.join(errors)}"
+        )
+    with outpath.open("w") as f:
+        f.writelines(needextend_texts)
+    typer.echo(f"Generated {outpath}")
+
+
 def load_config_from_toml(toml_file: Path) -> CodeLinksConfigType:
     try:
         with toml_file.open("rb") as f:
diff --git a/src/sphinx_codelinks/logger.py b/src/sphinx_codelinks/logger.py
new file mode 100644
index 0000000..05b3f35
--- /dev/null
+++ b/src/sphinx_codelinks/logger.py
@@ -0,0 +1,94 @@
+from rich.console import Console
+from rich.text import Text
+import typer
+
+
+class Logger:
+    __slots__ = ("console", "err_console", "quiet", "verbose")
+
+    def __init__(self, *, verbose: bool = False, quiet: bool = False) -> None:
+        self.verbose = verbose
+        self.quiet = quiet
+        self.console = Console()
+        self.err_console = Console(stderr=True)
+
+    def configure(self, verbose: bool = False, quiet: bool = False) -> None:
+        self.verbose = verbose
+        self.quiet = quiet
+
+    def debug(
+        self,
+        *msg: str | Text,
+        style: str | None = typer.colors.BRIGHT_BLACK,
+        highlight: bool = False,
+        markup: bool = False,
+        console: Console | None = None,
+    ) -> None:
+        """Print a debug message.
+
+        Will only be shown if verbose mode is enabled and not in quiet mode.
+        """
+        if self.verbose and not self.quiet:
+            (console or self.console).print(
+                *msg, style=style, highlight=highlight, markup=markup
+            )
+
+    def info(
+        self,
+        *msg: str | Text,
+        style: str | None = None,
+        highlight: bool = False,
+        markup: bool = False,
+        no_wrap: bool | None = None,
+        console: Console | None = None,
+    ) -> None:
+        """Print an informational message.
+
+        Will be suppressed in quiet mode.
+        """
+        if not self.quiet:
+            (console or self.console).print(
+                *msg, style=style, highlight=highlight, markup=markup, no_wrap=no_wrap
+            )
+
+    def result(
+        self,
+        *msg: str | Text,
+        style: str | None = None,
+        highlight: bool = False,
+        markup: bool = False,
+        console: Console | None = None,
+    ) -> None:
+        """Print a result message, like info but ignores quiet mode."""
+        (console or self.console).print(
+            *msg, style=style, highlight=highlight, markup=markup
+        )
+
+    def warning(
+        self,
+        *msg: str | Text,
+        style: str | None = typer.colors.YELLOW,
+        highlight: bool = False,
+        markup: bool = False,
+        console: Console | None = None,
+    ) -> None:
+        """Print a warning message."""
+        (console or self.console).print(
+            *msg, style=style, highlight=highlight, markup=markup
+        )
+
+    def error(
+        self,
+        *msg: str | Text,
+        style: str | None = typer.colors.RED,
+        highlight: bool = False,
+        markup: bool = False,
+        console: Console | None = None,
+    ) -> None:
+        """Print an error message."""
+        (console or self.err_console).print(
+            *msg, style=style, highlight=highlight, markup=markup
+        )
+
+
+logger = Logger()
diff --git a/src/sphinx_codelinks/needextend_write.py b/src/sphinx_codelinks/needextend_write.py
new file mode 100644
index 0000000..ee676d4
--- /dev/null
+++ b/src/sphinx_codelinks/needextend_write.py
@@ -0,0 +1,218 @@
+"""Covert the generated JSON file created by CodeLinks anaylse to need-extend in RST."""
+
+from collections import deque
+from dataclasses import MISSING, dataclass, field, fields
+from os import linesep
+from string import Template
+from typing import Any, TypedDict, cast
+
+from jsonschema import ValidationError, validate
+
+from sphinx_codelinks.analyse.models import MarkedContentType, SourceMap
+
+NEEDEXTEND_TEMPLATE = Template(""".. needextend:: $need_id
+   :$remote_url_field: $remote_url
+
+""")
+
+
+@dataclass
+class MarkedContentSchema:
+    @classmethod
+    def field_names(cls) -> set[str]:
+        return {item.name for item in fields(cls)}
+
+    filepath: str = field(
+        metadata={"schema": {"type": "string"}},
+    )
+    """filepath where the marked content is located."""
+
+    remote_url: str | None = field(
+        metadata={"schema": {"type": "string", "nullable": True}}
+    )
+    """remote url which can be directed to the the marked content."""
+
+    source_map: SourceMap = field(
+        metadata={
+            "schema": {
+                "type": "object",
+                "properties": {
+                    "start": {
+                        "type": "object",
+                        "properties": {
+                            "row": {"type": "integer"},
+                            "column": {"type": "integer"},
+                        },
+                        "required": ["row", "column"],
+                    },
+                    "end": {
+                        "type": "object",
+                        "properties": {
+                            "row": {"type": "integer"},
+                            "column": {"type": "integer"},
+                        },
+                        "required": ["row", "column"],
+                    },
+                },
+                "required": ["start", "end"],
+                "additionalProperties": False,
+            }
+        }
+    )
+    """Coordinate of the marked content in a file"""
+
+    tagged_scope: str | None = field(metadata={"schema": {"type": ["string", "null"]}})
+    """The scoped tagged by the marked content"""
+
+    type: MarkedContentType = field(
+        metadata={
+            "schema": {
+                "type": "string",
+                "enum": [key.value for key in MarkedContentType],
+            }
+        }
+    )
+    """Type of the marked content."""
+
+    marker: str | None = field(
+        default=None, metadata={"schema": {"type": ["string", "null"]}}
+    )
+    """Marker of the marked content."""
+
+    need_ids: list[str] | None = field(
+        default=None,
+        metadata={"schema": {"type": ["array", "null"], "items": {"type": "string"}}},
+    )
+    """Need id refs which is associated to the need items in the documentation."""
+    need: dict[str, str | list[str]] | None = field(
+        default=None,
+        metadata={
+            "schema": {
+                "type": ["object", "null"],
+                "properties": {"title": {"type": "string"}, "id": {"type": "string"}},
+                "required": ["title", "id"],
+                "additionalProperties": True,
+            }
+        },
+    )
+    """Definition of a need item"""
+
+    rst: str | None = field(
+        default=None, metadata={"schema": {"type": ["string", "null"]}}
+    )
+    """Extracted rst text."""
+
+    @classmethod
+    def get_schema(cls, name: str) -> dict[str, Any] | None:  # type: ignore[explicit-any]
+        _field = next(_field for _field in fields(cls) if _field.name is name)
+        if _field.metadata is not MISSING and "schema" in _field.metadata:
+            return cast(dict[str, Any], _field.metadata["schema"])  # type: ignore[explicit-any]
+        return None
+
+    def check_schema(self) -> list[str]:
+        errors = []
+        for _field_name in self.field_names():
+            schema = self.get_schema(_field_name)
+            value = getattr(self, _field_name)
+            try:
+                validate(instance=value, schema=schema)  # type: ignore[arg-type]  # validate has no type
+            except ValidationError as e:
+                errors.append(
+                    f"Schema validation error in field '{_field_name}': {e.message}"
+                )
+        return errors
+
+    def check_conditional_required_fields(self) -> list[str]:
+        errors = []
+        if self.type == MarkedContentType.need.value and not self.need:
+            errors.append(
+                "Need definition is required for marked content of type 'need'"
+            )
+        elif self.type == MarkedContentType.need_id_refs.value:
+            if not self.marker:
+                errors.append(
+                    "Marker is required for marked content of type 'need_id_refs'"
+                )
+            if not self.need_ids:
+                errors.append(
+                    "Need id refs are required for marked content of type 'need_id_refs'"
+                )
+        elif self.type == MarkedContentType.need.value and not self.need_ids:
+            errors.append(
+                "Need id refs are required for marked content of type 'need_id_refs'"
+            )
+        elif self.type == MarkedContentType.rst.value and not self.rst:
+            errors.append("RST text is required for marked content of type 'rst'")
+        return errors
+
+    def check_loaded_objs(self) -> list[str]:
+        return self.check_schema() + self.check_conditional_required_fields()
+
+
+class MarkedObjType(TypedDict):
+    filepath: str
+    remote_url: str | None
+    source_map: SourceMap
+    tagged_scope: str | None
+    type: MarkedContentType
+    need_ids: list[str] | None
+    need: dict[str, str | list[str]] | None
+    rst: str | None
+
+
+def convert_marked_content(
+    marked_objs: list[MarkedObjType],
+    remote_url_field: str = "remote-url",
+    title: str | None = None,
+) -> tuple[list[str], list[str]]:
+    """Convert marked objects extracted by anaylse CLI to needextend in RST"""
+    errors = []
+    needextend_texts: list[str] = []
+    intersted_objs = [
+        obj
+        for obj in marked_objs
+        if obj["type"] == MarkedContentType.need_id_refs.value
+    ]
+
+    for obj in intersted_objs:
+        try:
+            schema = MarkedContentSchema(**obj)
+        except TypeError as e:
+            errors.append(str(e))
+            continue
+        obj_errors: deque[str] = deque()
+        obj_errors.extend(schema.check_schema())
+        obj_errors.extend(schema.check_conditional_required_fields())
+        if obj_errors:
+            obj_errors.appendleft(f"{obj} has the following errors:")
+            errors.extend(list(obj_errors))
+
+    if errors:
+        return needextend_texts, errors
+
+    # handle N:1 mapping of need_id and remote_url
+    id_urls: dict[str, list[str]] = {}
+    for obj in intersted_objs:
+        if obj["type"] == MarkedContentType.need_id_refs.value and obj["need_ids"]:
+            for need_id in obj["need_ids"]:
+                if need_id not in id_urls:
+                    id_urls[need_id] = []
+                if obj["remote_url"]:
+                    id_urls[need_id].append(obj["remote_url"])
+
+    if title:
+        needextend_texts.append(f"{title}{linesep}{'=' * len(title)}{linesep}{linesep}")
+
+    for id, urls in id_urls.items():
+        # Connect urls with comma, if there are multiple urls
+        if not urls:
+            continue
+        remote_url = ",".join(urls)
+        needextend_text = NEEDEXTEND_TEMPLATE.safe_substitute(
+            need_id=id,
+            remote_url_field=remote_url_field,
+            remote_url=remote_url,
+        )
+        needextend_texts.append(needextend_text)
+
+    return needextend_texts, errors
diff --git a/tests/__snapshots__/test_analyse/test_analyse[src_dir0-src_paths0].anchors.json b/tests/__snapshots__/test_analyse/test_analyse[src_dir0-src_paths0].anchors.json
index 02b3285..1904a62 100644
--- a/tests/__snapshots__/test_analyse/test_analyse[src_dir0-src_paths0].anchors.json
+++ b/tests/__snapshots__/test_analyse/test_analyse[src_dir0-src_paths0].anchors.json
@@ -48,10 +48,10 @@
     },
     "tagged_scope": "void dummy_func1(){\n     //...\n }",
     "need_ids": [
-      "need_001",
-      "need_002",
-      "need_003",
-      "need_004"
+      "NEED_001",
+      "NEED_002",
+      "NEED_003",
+      "NEED_004"
     ],
     "marker": "@need-ids:",
     "type": "need-id-refs"
@@ -71,7 +71,7 @@
     },
     "tagged_scope": "int main() {\n   std::cout << \"Starting demo_1...\" << std::endl;\n   dummy_func1();\n   std::cout << \"Demo_1 finished.\" << std::endl;\n   return 0;\n }",
     "need_ids": [
-      "need_003"
+      "NEED_003"
     ],
     "marker": "@need-ids:",
     "type": "need-id-refs"
diff --git a/tests/data/analyse/marked_content.json b/tests/data/analyse/marked_content.json
new file mode 100644
index 0000000..e8ad425
--- /dev/null
+++ b/tests/data/analyse/marked_content.json
@@ -0,0 +1,114 @@
+{
+  "full_config": [
+    {
+      "filepath": "/home/jui-wen/git_repo/ub/sphinx-codelinks/tests/data/marked_rst/dummy_1.cpp",
+      "remote_url": "https://github.com/useblocks/sphinx-codelinks/blob/951e40e7845f06d5cfc4ca20ebb984308fdaf985/tests/data/marked_rst/dummy_1.cpp#L4",
+      "source_map": {
+        "start": { "row": 3, "column": 8 },
+        "end": { "row": 3, "column": 61 }
+      },
+      "tagged_scope": "void dummy_func1(){\n     //...\n }",
+      "rst": ".. impl:: implement dummy function 1\n   :id: IMPL_71\n",
+      "type": "rst"
+    },
+    {
+      "filepath": "/home/jui-wen/git_repo/ub/sphinx-codelinks/tests/data/marked_rst/dummy_1.cpp",
+      "remote_url": "https://github.com/useblocks/sphinx-codelinks/blob/951e40e7845f06d5cfc4ca20ebb984308fdaf985/tests/data/marked_rst/dummy_1.cpp#L14",
+      "source_map": {
+        "start": { "row": 13, "column": 7 },
+        "end": { "row": 13, "column": 40 }
+      },
+      "tagged_scope": "int main() {\n   std::cout << \"Starting demo_1...\" << std::endl;\n   dummy_func1();\n   std::cout << \"Demo_1 finished.\" << std::endl;\n   return 0;\n }",
+      "rst": "..impl:: implement main function ",
+      "type": "rst"
+    },
+    {
+      "filepath": "/home/jui-wen/git_repo/ub/sphinx-codelinks/tests/data/need_id_refs/dummy_1.cpp",
+      "remote_url": "https://github.com/useblocks/sphinx-codelinks/blob/951e40e7845f06d5cfc4ca20ebb984308fdaf985/tests/data/need_id_refs/dummy_1.cpp#L3",
+      "source_map": {
+        "start": { "row": 2, "column": 13 },
+        "end": { "row": 2, "column": 51 }
+      },
+      "tagged_scope": "void dummy_func1(){\n     //...\n }",
+      "need_ids": ["NEED_001", "NEED_002", "NEED_003", "NEED_004"],
+      "marker": "@need-ids:",
+      "type": "need-id-refs"
+    },
+    {
+      "filepath": "/home/jui-wen/git_repo/ub/sphinx-codelinks/tests/data/need_id_refs/dummy_1.cpp",
+      "remote_url": "https://github.com/useblocks/sphinx-codelinks/blob/951e40e7845f06d5cfc4ca20ebb984308fdaf985/tests/data/need_id_refs/dummy_1.cpp#L8",
+      "source_map": {
+        "start": { "row": 7, "column": 13 },
+        "end": { "row": 7, "column": 21 }
+      },
+      "tagged_scope": "int main() {\n   std::cout << \"Starting demo_1...\" << std::endl;\n   dummy_func1();\n   std::cout << \"Demo_1 finished.\" << std::endl;\n   return 0;\n }",
+      "need_ids": ["NEED_003"],
+      "marker": "@need-ids:",
+      "type": "need-id-refs"
+    },
+    {
+      "filepath": "/home/jui-wen/git_repo/ub/sphinx-codelinks/tests/data/oneline_comment_default/default_oneliners.c",
+      "remote_url": "https://github.com/useblocks/sphinx-codelinks/blob/951e40e7845f06d5cfc4ca20ebb984308fdaf985/tests/data/oneline_comment_default/default_oneliners.c#L1",
+      "source_map": {
+        "start": { "row": 0, "column": 4 },
+        "end": { "row": 0, "column": 24 }
+      },
+      "tagged_scope": "void foo() {}",
+      "need": {
+        "title": "Function Foo",
+        "id": "IMPL_1",
+        "type": "impl",
+        "links": []
+      },
+      "type": "need"
+    },
+    {
+      "filepath": "/home/jui-wen/git_repo/ub/sphinx-codelinks/tests/data/oneline_comment_default/default_oneliners.c",
+      "remote_url": "https://github.com/useblocks/sphinx-codelinks/blob/951e40e7845f06d5cfc4ca20ebb984308fdaf985/tests/data/oneline_comment_default/default_oneliners.c#L4",
+      "source_map": {
+        "start": { "row": 3, "column": 4 },
+        "end": { "row": 3, "column": 24 }
+      },
+      "tagged_scope": "void bar() {}",
+      "need": {
+        "title": "Function Bar",
+        "id": "IMPL_2",
+        "type": "impl",
+        "links": []
+      },
+      "type": "need"
+    },
+    {
+      "filepath": "/home/jui-wen/git_repo/ub/sphinx-codelinks/tests/data/oneline_comment_default/default_oneliners.c",
+      "remote_url": "https://github.com/useblocks/sphinx-codelinks/blob/951e40e7845f06d5cfc4ca20ebb984308fdaf985/tests/data/oneline_comment_default/default_oneliners.c#L7",
+      "source_map": {
+        "start": { "row": 6, "column": 4 },
+        "end": { "row": 6, "column": 39 }
+      },
+      "tagged_scope": "void baz() {}",
+      "need": {
+        "title": "Function Baz, as I want it",
+        "id": "IMPL_3",
+        "type": "impl",
+        "links": []
+      },
+      "type": "need"
+    },
+    {
+      "filepath": "/home/jui-wen/git_repo/ub/sphinx-codelinks/tests/data/oneline_comment_default/default_oneliners.c",
+      "remote_url": "https://github.com/useblocks/sphinx-codelinks/blob/951e40e7845f06d5cfc4ca20ebb984308fdaf985/tests/data/oneline_comment_default/default_oneliners.c#L10",
+      "source_map": {
+        "start": { "row": 9, "column": 4 },
+        "end": { "row": 9, "column": 51 }
+      },
+      "tagged_scope": "void bar() {}",
+      "need": {
+        "title": "Function Bar,",
+        "id": "IMPL_4",
+        "type": "impl",
+        "links": ["SPEC_1", "SPEC_2"]
+      },
+      "type": "need"
+    }
+  ]
+}
diff --git a/tests/data/need_id_refs/dummy_1.cpp b/tests/data/need_id_refs/dummy_1.cpp
index 86b7b2f..6d90ed2 100644
--- a/tests/data/need_id_refs/dummy_1.cpp
+++ b/tests/data/need_id_refs/dummy_1.cpp
@@ -1,11 +1,11 @@
  #include <iostream>
 
-// @need-ids: need_001, need_002, need_003, need_004
+// @need-ids: NEED_001, NEED_002, NEED_003, NEED_004
  void dummy_func1(){
      //...
  }
 
- // @need-ids: need_003
+ // @need-ids: NEED_003
 int main() {
    std::cout << "Starting demo_1..." << std::endl;
    dummy_func1();
diff --git a/tests/data/needextend_demo/README.md b/tests/data/needextend_demo/README.md
new file mode 100644
index 0000000..4070635
--- /dev/null
+++ b/tests/data/needextend_demo/README.md
@@ -0,0 +1,7 @@
+# Needextend Demo
+
+Run the following command in project root to have demo generated
+
+```bash
+rye run demo:clean
+```
diff --git a/tests/data/needextend_demo/conf.py b/tests/data/needextend_demo/conf.py
new file mode 100644
index 0000000..2cef3d0
--- /dev/null
+++ b/tests/data/needextend_demo/conf.py
@@ -0,0 +1,38 @@
+# Configuration file for the Sphinx documentation builder.
+#
+# For the full list of built-in configuration values, see the documentation:
+# https://www.sphinx-doc.org/en/master/usage/configuration.html
+
+# -- Project information -----------------------------------------------------
+# https://www.sphinx-doc.org/en/master/usage/configuration.html#project-information
+
+project = "test_needextend"
+copyright = "2025, useblocks"
+author = "team useblocks"
+
+# -- General configuration ---------------------------------------------------
+# https://www.sphinx-doc.org/en/master/usage/configuration.html#general-configuration
+
+templates_path = ["_templates"]
+exclude_patterns = ["_build", "Thumbs.db", ".DS_Store"]
+
+
+# -- Options for HTML output -------------------------------------------------
+# https://www.sphinx-doc.org/en/master/usage/configuration.html#options-for-html-output
+
+html_theme = "furo"
+# html_static_path = ["_static"]
+
+extensions = ["sphinx_needs", "sphinx_codelinks"]
+
+# for needextend to work with remote url
+needs_extra_options = ["remote_url"]
+
+needs_string_links = {
+    "custom_name": {
+        "regex": r"^(?P<value>.+)#L(?P<lineno>.*)?",
+        "link_url": "{url}",
+        "link_name": "{{value}}#L{{lineno}}",
+        "options": ["remote_url"],
+    }
+}
diff --git a/tests/data/needextend_demo/index.rst b/tests/data/needextend_demo/index.rst
new file mode 100644
index 0000000..13d2c1d
--- /dev/null
+++ b/tests/data/needextend_demo/index.rst
@@ -0,0 +1,13 @@
+.. impl:: title 1
+    :id: NEED_001
+
+.. impl:: title 2
+    :id: NEED_002
+
+.. impl:: title 3
+    :id: NEED_003
+
+.. impl:: title 4
+    :id: NEED_004
+
+.. include:: needextend.rst
diff --git a/tests/data/needextend_demo/needextend.rst b/tests/data/needextend_demo/needextend.rst
new file mode 100644
index 0000000..5d932dd
--- /dev/null
+++ b/tests/data/needextend_demo/needextend.rst
@@ -0,0 +1,14 @@
+.. needextend:: NEED_001
+   :remote_url: https://github.com/useblocks/sphinx-codelinks/blob/1759d19e8694c049c68e7f95ce93d951d1ed0336/tests/data/need_id_refs/dummy_1.cpp#L3
+
+.. needextend:: NEED_002
+   :remote_url: https://github.com/useblocks/sphinx-codelinks/blob/1759d19e8694c049c68e7f95ce93d951d1ed0336/tests/data/need_id_refs/dummy_1.cpp#L3
+
+.. needextend:: NEED_003
+   :remote_url: https://github.com/useblocks/sphinx-codelinks/blob/1759d19e8694c049c68e7f95ce93d951d1ed0336/tests/data/need_id_refs/dummy_1.cpp#L3
+
+.. needextend:: NEED_004
+   :remote_url: https://github.com/useblocks/sphinx-codelinks/blob/1759d19e8694c049c68e7f95ce93d951d1ed0336/tests/data/need_id_refs/dummy_1.cpp#L3
+
+.. needextend:: NEED_003
+   :remote_url: https://github.com/useblocks/sphinx-codelinks/blob/1759d19e8694c049c68e7f95ce93d951d1ed0336/tests/data/need_id_refs/dummy_1.cpp#L8
diff --git a/tests/test_cmd.py b/tests/test_cmd.py
index 6d5adbd..60a4c2e 100644
--- a/tests/test_cmd.py
+++ b/tests/test_cmd.py
@@ -212,3 +212,73 @@ def test_analyse_project_negative(projects, output_lines, tmp_path: Path) -> Non
     assert result.exit_code != 0
     for line in output_lines:
         assert line in result.stdout
+
+
+def test_write_rst_invalid_json(tmp_path: Path) -> None:
+    json_obj = {
+        "whatever": "json",
+        "not": "expected",
+    }
+    json_text = json.dumps(json_obj)
+    json_text = json_text.replace(",", "")
+    jsonpath = tmp_path / "invalid_json.json"
+    with jsonpath.open("w") as f:
+        f.write(json_text)
+
+    options = [
+        "write",
+        "rst",
+        str(jsonpath),
+        "--outpath",
+        str(tmp_path / "out.rst"),
+    ]
+    result = runner.invoke(app, options)
+
+    assert result.exit_code != 0
+    assert "Expecting" in result.stdout
+
+
+@pytest.mark.parametrize(
+    ("json_objs", "output_lines"),
+    [
+        (
+            [
+                {
+                    "filepath": 123,
+                    "remote_url": "https://github.com/useblocks/sphinx-codelinks/blob/951e40e7845f06d5cfc4ca20ebb984308fdaf985/tests/data/marked_rst/dummy_1.cpp#L4",
+                    "source_map": {
+                        "start": {"row": 3, "column": 8},
+                        "end": {"row": 3, "column": 61},
+                    },
+                    "tagged_scope": "void dummy_func1(){\n     //...\n }",
+                    "rst": ".. impl:: implement dummy function 1\n   :id: IMPL_71\n",
+                    "type": "need-id-refs",
+                }
+            ],
+            [
+                "Invalid value: Errors occurred",
+                "Schema validation error in field 'filepath': 123 is not of type 'string'",
+                "Marker is required for marked content of type 'need_id_refs'",
+                "Need id refs are required for marked content of type 'need_id_refs'",
+            ],
+        ),
+    ],
+)
+def test_write_rst_negative(json_objs: list[dict], output_lines, tmp_path) -> None:
+    to_dump = {"project_1": json_objs}
+    jsonpath = Path("invalid_objs.json")
+    with jsonpath.open("w") as f:
+        json.dump(to_dump, f)
+    outpath = tmp_path / "needextend.rst"
+    options = [
+        "write",
+        "rst",
+        str(jsonpath),
+        "--outpath",
+        str(outpath),
+    ]
+    result = runner.invoke(app, options)
+
+    assert result.exit_code != 0
+    for line in output_lines:
+        assert line in result.stdout
diff --git a/tests/test_needextend_write.py b/tests/test_needextend_write.py
new file mode 100644
index 0000000..4a2342e
--- /dev/null
+++ b/tests/test_needextend_write.py
@@ -0,0 +1,71 @@
+import pytest
+
+from sphinx_codelinks.needextend_write import convert_marked_content
+
+
+@pytest.mark.parametrize(
+    ("markers", "texts"),
+    [
+        (
+            [
+                {
+                    "filepath": "/home/jui-wen/git_repo/ub/sphinx-codelinks/tests/data/need_id_refs/dummy_1.cpp",
+                    "remote_url": "https://github.com/useblocks/sphinx-codelinks/blob/main/tests/data/need_id_refs/dummy_1.cpp#L3",
+                    "source_map": {
+                        "start": {"row": 2, "column": 13},
+                        "end": {"row": 2, "column": 51},
+                    },
+                    "tagged_scope": "void dummy_func1(){\n     //...\n }",
+                    "need_ids": ["NEED_001", "NEED_002", "NEED_003", "NEED_004"],
+                    "marker": "@need-ids:",
+                    "type": "need-id-refs",
+                },
+            ],
+            [
+                ".. needextend:: NEED_001\n   :remote-url: https://github.com/useblocks/sphinx-codelinks/blob/main/tests/data/need_id_refs/dummy_1.cpp#L3\n\n",
+                ".. needextend:: NEED_002\n   :remote-url: https://github.com/useblocks/sphinx-codelinks/blob/main/tests/data/need_id_refs/dummy_1.cpp#L3\n\n",
+                ".. needextend:: NEED_003\n   :remote-url: https://github.com/useblocks/sphinx-codelinks/blob/main/tests/data/need_id_refs/dummy_1.cpp#L3\n\n",
+                ".. needextend:: NEED_004\n   :remote-url: https://github.com/useblocks/sphinx-codelinks/blob/main/tests/data/need_id_refs/dummy_1.cpp#L3\n\n",
+            ],
+        ),
+        (
+            [
+                {
+                    "filepath": "/home/jui-wen/git_repo/ub/sphinx-codelinks/tests/data/need_id_refs/dummy_1.cpp",
+                    "remote_url": "https://github.com/useblocks/sphinx-codelinks/blob/main/tests/data/need_id_refs/dummy_1.cpp#L3",
+                    "source_map": {
+                        "start": {"row": 2, "column": 13},
+                        "end": {"row": 2, "column": 51},
+                    },
+                    "tagged_scope": "void dummy_func1(){\n     //...\n }",
+                    "need_ids": ["NEED_001"],
+                    "marker": "@need-ids:",
+                    "type": "need-id-refs",
+                },
+                {
+                    "filepath": "/home/jui-wen/git_repo/ub/sphinx-codelinks/tests/data/need_id_refs/dummy_1.cpp",
+                    "remote_url": "https://github.com/useblocks/sphinx-codelinks/blob/main/tests/data/need_id_refs/dummy_1.cpp#L10",
+                    "source_map": {
+                        "start": {"row": 2, "column": 13},
+                        "end": {"row": 2, "column": 51},
+                    },
+                    "tagged_scope": "void dummy_func1(){\n     //...\n }",
+                    "need_ids": ["NEED_001"],
+                    "marker": "@need-ids:",
+                    "type": "need-id-refs",
+                },
+            ],
+            [
+                ".. needextend:: NEED_001\n   :remote-url: https://github.com/useblocks/sphinx-codelinks/blob/main/tests/data/need_id_refs/dummy_1.cpp#L3,https://github.com/useblocks/sphinx-codelinks/blob/main/tests/data/need_id_refs/dummy_1.cpp#L10\n\n"
+            ],
+        ),
+    ],
+)
+def test_convert_marked_content(markers, texts):
+    # Normalize line endings
+    texts = [line.replace("\r\n", "\n").replace("\r", "\n") for line in texts]
+    needextend_texts, errors = convert_marked_content(markers)
+
+    assert not errors
+
+    assert needextend_texts == texts