Documentation

01 · OVERVIEW

One PDF. One publication.

FLDR turns a finished PDF into a responsive online publication. Readers open it in a browser; you keep control of the source, presentation and public link.

Upload

Choose a finished PDF or send it through an integration.

Prepare

FLDR securely checks the file and renders its cover and pages.

Publish

Review the result, then share one stable FLDR link.

02 · FOR EVERYONE

Publish a PDF without code.

You can start before creating an account. FLDR keeps the upload private while it prepares your preview; you sign in or claim it only when you are ready to publish.

1
Choose your PDF
Open fldr.be and select a PDF, or drop it anywhere on the page. The upload starts immediately after a quick file check.
2
Let FLDR prepare it
FLDR validates the document, creates the cover and renders the pages. Small files may take a few minutes; large, image-heavy or high-page-count files take longer.
3
Review the private preview
Check the title, address, page order and presentation. The publication remains private until you choose Publish.
4
Customize the publication
Open Customize to change the title, link, background, page transition, logo, reader controls, access and analytics. The full list is explained below.
5
Publish and copy the link
Sign in with a secure email link if needed, then choose Publish. Copy the public URL from the publication bar.

03 · PUBLICATION CONTROLS

Customize, share and manage a publication.

Use Customize and Share in the publication bar. Replace PDF and Statistics are available from the more-actions menu (•••).

Customize

Open Customize from the publication bar. After publishing, changes save automatically. Before publishing, they are applied when you publish.

Publication

Change the publication title.
Set the public FLDR address.

Design

Choose Automatic, Light, Dark or a custom background.
Select Fade or Slide and set the transition speed.
Add, replace, hide or remove a publisher logo.

Reader

Allow or disable PDF downloads.
Show or hide sharing and page thumbnails.
Enable Ask this publication for page-linked answers.
Allow search engines and AI tools with Discoverable.
Require a 4–64 character passcode.
Enable or disable privacy-first analytics.

A passcode-protected publication cannot be Discoverable. Removing the passcode lets you enable Discoverable again.

Share a publication

Choose Copy link for the main publication URL, or open Share for the following options:

Current page link

Copy a link that opens on the page currently shown in the preview.

QR code

Download a PNG QR code that points to the publication URL.

Email snippet

Copy a small HTML link for an email or newsletter.

Open catalogue

Open the public reader in a new browser tab.

Responsive embed

Copy an iframe for your website and optionally use a transparent background.

FLDR credit

Show or hide the FLDR credit in embeds when your plan allows it.

If a publication requires a passcode, the same passcode screen protects both the shared link and the embed.

RESPONSIVE EMBED — COPY THE GENERATED VERSION FROM SHARE

<iframe
  src="https://www.fldr.be/your-publication?embed=1"
  width="100%"
  height="700"
  style="border:0;border-radius:12px"
  loading="lazy"
  allow="fullscreen">
</iframe>

View statistics

Open ••• and choose Statistics. Select 30, 60, 90 or 180 days, or one year.

Reading activity

Views over time, estimated visitors, pages per visit, average reading time and downloads.

Content performance

The three most-viewed pages for the selected period.

Reader context

Direct versus embedded views and the phone, tablet and desktop split.

PDF report

Download or share a PDF summary for the selected period.

Privacy-first analytics contain aggregate activity only and do not create profiles of individual readers. When analytics are disabled, FLDR does not count views.

Replace the PDF

1. Open ••• and choose Replace PDF.
2. Select or drop the new PDF.
3. Wait while FLDR prepares every page. The current version remains live.
4. Choose Activate replacement when the new version is ready.

The publication URL, QR code and embed do not change. Readers see the replacement on their next visit.

04 · REST API

Automate PDF publishing.

The REST API coordinates a direct upload to private object storage, starts processing and returns status. Large PDF bodies never pass through the catalogue endpoint.

Create an API key

Go to Settings → API & MCP → Create new key. The full key is shown once; store it in a secret manager and never expose it in browser code.

Create an API key

AUTHENTICATION

Authorization: Bearer fldr_sk_…
Base URL: https://www.fldr.be

1. Reserve the upload

Send the exact byte size. Set publishWhenReady to true only when a successful account upload should go public as soon as processing finishes.

POST /API/V1/CATALOGUES

curl --request POST 'https://www.fldr.be/api/v1/catalogues' \
  --header "Authorization: Bearer ${FLDR_API_KEY}" \
  --header 'Content-Type: application/json' \
  --data '{
    "filename": "spring-collection.pdf",
    "fileSize": 2482314,
    "title": "Spring Collection",
    "publishWhenReady": false
  }'

A successful 201 response includes id, versionId, direct upload instructions, a completeUrl and a statusUrl.

2. Upload the exact PDF bytes

For files up to 100 MB, the response uses upload.mode: single. PUT the bytes to the returned URL with every returned header. Do not send the FLDR API key to the storage URL.

DIRECT UPLOAD — VALUES COME FROM THE RESERVATION RESPONSE

curl --request PUT "${UPLOAD_URL}" \
  --header 'Content-Type: application/pdf' \
  --data-binary '@spring-collection.pdf'

Larger account files use multipart. Upload each returned part, retain its ETag, then send the ordered part manifest when completing the upload.

Multipart completion body

POST /API/V1/CATALOGUES/{ID}/COMPLETE

{
  "multipart": {
    "uploadId": "…",
    "parts": [
      { "partNumber": 1, "etag": ""…"" }
    ]
  }
}

3. Complete, poll and publish

Completion is idempotent. Poll the status URL until the version is ready or failed, and use backoff for long-running files. Publish only after canPublish is true.

COMPLETE → STATUS → PUBLISH

curl --request POST "https://www.fldr.be/api/v1/catalogues/${ID}/complete" \
  --header "Authorization: Bearer ${FLDR_API_KEY}"

curl "https://www.fldr.be/api/v1/catalogues/${ID}" \
  --header "Authorization: Bearer ${FLDR_API_KEY}"

curl --request POST "https://www.fldr.be/api/v1/catalogues/${ID}/publish" \
  --header "Authorization: Bearer ${FLDR_API_KEY}"

05 · API REFERENCE

Four endpoints. One lifecycle.

Reserve → direct upload → complete → process → publish. All JSON responses use no-store caching; error responses contain an error code and human-readable message.

METHOD	PATH	PURPOSE	AUTH
POST	/api/v1/catalogues	Reserve an upload and receive direct-upload instructions.	Optional
POST	/api/v1/catalogues/{id}/complete	Confirm the upload and start PDF processing.	Required
GET	/api/v1/catalogues/{id}	Read progress, preview and public-link status.	Required
POST	/api/v1/catalogues/{id}/publish	Publish a ready, account-owned publication.	Account key

REPRESENTATIVE STATUS RESPONSE

{
  "id": "…",
  "title": "Spring Collection",
  "status": "draft",
  "version": {
    "status": "processing",
    "stage": "rendering_pages",
    "progress": 48,
    "pageCount": null,
    "failure": null
  },
  "previewUrl": null,
  "publicUrl": null,
  "canPublish": false
}

FLDR does not currently expose webhooks or an official SDK. Poll the returned status URL to follow processing.

06 · MODEL CONTEXT PROTOCOL

Connect an MCP client.

FLDR exposes a stateless Streamable HTTP MCP server. Connect anonymously for a temporary private preview, or add a FLDR API key for account-owned publishing.

MCP ENDPOINT

https://www.fldr.be/api/mcp

OPTIONAL AUTHENTICATION

Authorization: Bearer fldr_sk_…

MCP clients name their connection fields differently. Choose Streamable HTTP, use the endpoint above and add the Authorization header only for an account connection.

upload_pdf

Fetch a PDF, upload it and start processing.

file, optional title, publish_when_ready, appearance, custom_background

set_publication_appearance

Choose Automatic, Light, Dark or a custom reader background.

publication_id, appearance, optional custom_background

get_publication_status

Read stage, progress, preview and live link.

publication_id, optional guest_bearer_token

publish_publication

Make a ready account-owned publication public.

publication_id

07 · LIMITS

Current upload limits and API errors.

PATH	FILE SIZE*	PAGES*	NOTES
Web app	200 MB	300	Upload through fldr.be
Account REST	200 MB	300	Multipart above 100 MB
Guest REST	25 MB	300	Private preview; expires after seven days
MCP	25 MB	300	Remote HTTPS file; redirects are blocked

* These are FLDR's initial operating limits, not permanent product ceilings. FLDR will increase them as processing capacity and reliability grow. The values above are the limits currently supported.

Common API responses

401 · invalid_api_key: Create a valid key, then send it as a Bearer token.
403 · claim_required: A guest preview must be claimed before it can be published.
409 · upload_incomplete: The direct upload is missing, partial or has the wrong byte size.
409 · version_not_ready: Keep polling; the PDF is still being prepared.
413 · guest_file_too_large: Use an account key for PDFs larger than 25 MB.
415 · invalid_pdf: Export a complete PDF again and repeat the upload.
429 · guest_rate_limited: Pause and retry later, or use an account API key.

08 · HELP

Bring the file, link or error code.

If an upload keeps failing, include the PDF size, page count, route used (web, REST or MCP) and the exact error code. Never email an API key or guest bearer token.

Contact support

Send the publication link or request details. For content safety or legal notices, use the dedicated report flow.

Email support Report content

01 · OVERVIEW

One PDF. One publication.

FLDR turns a finished PDF into a responsive online publication. Readers open it in a browser; you keep control of the source, presentation and public link.

Upload

Choose a finished PDF or send it through an integration.

Prepare

FLDR securely checks the file and renders its cover and pages.

Publish

Review the result, then share one stable FLDR link.

02 · FOR EVERYONE

Publish a PDF without code.

You can start before creating an account. FLDR keeps the upload private while it prepares your preview; you sign in or claim it only when you are ready to publish.

1
Choose your PDF
Open fldr.be and select a PDF, or drop it anywhere on the page. The upload starts immediately after a quick file check.
2
Let FLDR prepare it
FLDR validates the document, creates the cover and renders the pages. Small files may take a few minutes; large, image-heavy or high-page-count files take longer.
3
Review the private preview
Check the title, address, page order and presentation. The publication remains private until you choose Publish.
4
Customize the publication
Open Customize to change the title, link, background, page transition, logo, reader controls, access and analytics. The full list is explained below.
5
Publish and copy the link
Sign in with a secure email link if needed, then choose Publish. Copy the public URL from the publication bar.

03 · PUBLICATION CONTROLS

Customize, share and manage a publication.

Use Customize and Share in the publication bar. Replace PDF and Statistics are available from the more-actions menu (•••).

Customize

Open Customize from the publication bar. After publishing, changes save automatically. Before publishing, they are applied when you publish.

Publication

Change the publication title.
Set the public FLDR address.

Design

Choose Automatic, Light, Dark or a custom background.
Select Fade or Slide and set the transition speed.
Add, replace, hide or remove a publisher logo.

Reader

Allow or disable PDF downloads.
Show or hide sharing and page thumbnails.
Enable Ask this publication for page-linked answers.
Allow search engines and AI tools with Discoverable.
Require a 4–64 character passcode.
Enable or disable privacy-first analytics.

A passcode-protected publication cannot be Discoverable. Removing the passcode lets you enable Discoverable again.

Share a publication

Choose Copy link for the main publication URL, or open Share for the following options:

Current page link

Copy a link that opens on the page currently shown in the preview.

QR code

Download a PNG QR code that points to the publication URL.

Email snippet

Copy a small HTML link for an email or newsletter.

Open catalogue

Open the public reader in a new browser tab.

Responsive embed

Copy an iframe for your website and optionally use a transparent background.

FLDR credit

Show or hide the FLDR credit in embeds when your plan allows it.

If a publication requires a passcode, the same passcode screen protects both the shared link and the embed.

RESPONSIVE EMBED — COPY THE GENERATED VERSION FROM SHARE

<iframe
  src="https://www.fldr.be/your-publication?embed=1"
  width="100%"
  height="700"
  style="border:0;border-radius:12px"
  loading="lazy"
  allow="fullscreen">
</iframe>

View statistics

Open ••• and choose Statistics. Select 30, 60, 90 or 180 days, or one year.

Reading activity

Views over time, estimated visitors, pages per visit, average reading time and downloads.

Content performance

The three most-viewed pages for the selected period.

Reader context

Direct versus embedded views and the phone, tablet and desktop split.

PDF report

Download or share a PDF summary for the selected period.

Privacy-first analytics contain aggregate activity only and do not create profiles of individual readers. When analytics are disabled, FLDR does not count views.

Replace the PDF

1. Open ••• and choose Replace PDF.
2. Select or drop the new PDF.
3. Wait while FLDR prepares every page. The current version remains live.
4. Choose Activate replacement when the new version is ready.

The publication URL, QR code and embed do not change. Readers see the replacement on their next visit.

04 · REST API

Automate PDF publishing.

The REST API coordinates a direct upload to private object storage, starts processing and returns status. Large PDF bodies never pass through the catalogue endpoint.

Create an API key

Go to Settings → API & MCP → Create new key. The full key is shown once; store it in a secret manager and never expose it in browser code.

Create an API key

AUTHENTICATION

Authorization: Bearer fldr_sk_…
Base URL: https://www.fldr.be

1. Reserve the upload

Send the exact byte size. Set publishWhenReady to true only when a successful account upload should go public as soon as processing finishes.

POST /API/V1/CATALOGUES

curl --request POST 'https://www.fldr.be/api/v1/catalogues' \
  --header "Authorization: Bearer ${FLDR_API_KEY}" \
  --header 'Content-Type: application/json' \
  --data '{
    "filename": "spring-collection.pdf",
    "fileSize": 2482314,
    "title": "Spring Collection",
    "publishWhenReady": false
  }'

A successful 201 response includes id, versionId, direct upload instructions, a completeUrl and a statusUrl.

2. Upload the exact PDF bytes

For files up to 100 MB, the response uses upload.mode: single. PUT the bytes to the returned URL with every returned header. Do not send the FLDR API key to the storage URL.

DIRECT UPLOAD — VALUES COME FROM THE RESERVATION RESPONSE

curl --request PUT "${UPLOAD_URL}" \
  --header 'Content-Type: application/pdf' \
  --data-binary '@spring-collection.pdf'

Larger account files use multipart. Upload each returned part, retain its ETag, then send the ordered part manifest when completing the upload.

Multipart completion body

POST /API/V1/CATALOGUES/{ID}/COMPLETE

{
  "multipart": {
    "uploadId": "…",
    "parts": [
      { "partNumber": 1, "etag": ""…"" }
    ]
  }
}

3. Complete, poll and publish

Completion is idempotent. Poll the status URL until the version is ready or failed, and use backoff for long-running files. Publish only after canPublish is true.

COMPLETE → STATUS → PUBLISH

curl --request POST "https://www.fldr.be/api/v1/catalogues/${ID}/complete" \
  --header "Authorization: Bearer ${FLDR_API_KEY}"

curl "https://www.fldr.be/api/v1/catalogues/${ID}" \
  --header "Authorization: Bearer ${FLDR_API_KEY}"

curl --request POST "https://www.fldr.be/api/v1/catalogues/${ID}/publish" \
  --header "Authorization: Bearer ${FLDR_API_KEY}"

05 · API REFERENCE

Four endpoints. One lifecycle.

Reserve → direct upload → complete → process → publish. All JSON responses use no-store caching; error responses contain an error code and human-readable message.

METHOD	PATH	PURPOSE	AUTH
POST	/api/v1/catalogues	Reserve an upload and receive direct-upload instructions.	Optional
POST	/api/v1/catalogues/{id}/complete	Confirm the upload and start PDF processing.	Required
GET	/api/v1/catalogues/{id}	Read progress, preview and public-link status.	Required
POST	/api/v1/catalogues/{id}/publish	Publish a ready, account-owned publication.	Account key

REPRESENTATIVE STATUS RESPONSE

{
  "id": "…",
  "title": "Spring Collection",
  "status": "draft",
  "version": {
    "status": "processing",
    "stage": "rendering_pages",
    "progress": 48,
    "pageCount": null,
    "failure": null
  },
  "previewUrl": null,
  "publicUrl": null,
  "canPublish": false
}

FLDR does not currently expose webhooks or an official SDK. Poll the returned status URL to follow processing.

06 · MODEL CONTEXT PROTOCOL

Connect an MCP client.

FLDR exposes a stateless Streamable HTTP MCP server. Connect anonymously for a temporary private preview, or add a FLDR API key for account-owned publishing.

MCP ENDPOINT

https://www.fldr.be/api/mcp

OPTIONAL AUTHENTICATION

Authorization: Bearer fldr_sk_…

MCP clients name their connection fields differently. Choose Streamable HTTP, use the endpoint above and add the Authorization header only for an account connection.

upload_pdf

Fetch a PDF, upload it and start processing.

file, optional title, publish_when_ready, appearance, custom_background

set_publication_appearance

Choose Automatic, Light, Dark or a custom reader background.

publication_id, appearance, optional custom_background

get_publication_status

Read stage, progress, preview and live link.

publication_id, optional guest_bearer_token

publish_publication

Make a ready account-owned publication public.

publication_id

07 · LIMITS

Current upload limits and API errors.

PATH	FILE SIZE*	PAGES*	NOTES
Web app	200 MB	300	Upload through fldr.be
Account REST	200 MB	300	Multipart above 100 MB
Guest REST	25 MB	300	Private preview; expires after seven days
MCP	25 MB	300	Remote HTTPS file; redirects are blocked

* These are FLDR's initial operating limits, not permanent product ceilings. FLDR will increase them as processing capacity and reliability grow. The values above are the limits currently supported.

Common API responses

401 · invalid_api_key: Create a valid key, then send it as a Bearer token.
403 · claim_required: A guest preview must be claimed before it can be published.
409 · upload_incomplete: The direct upload is missing, partial or has the wrong byte size.
409 · version_not_ready: Keep polling; the PDF is still being prepared.
413 · guest_file_too_large: Use an account key for PDFs larger than 25 MB.
415 · invalid_pdf: Export a complete PDF again and repeat the upload.
429 · guest_rate_limited: Pause and retry later, or use an account API key.

08 · HELP

Bring the file, link or error code.

If an upload keeps failing, include the PDF size, page count, route used (web, REST or MCP) and the exact error code. Never email an API key or guest bearer token.

Contact support

Send the publication link or request details. For content safety or legal notices, use the dedicated report flow.

Email support Report content

One PDF. One publication.

Upload

Prepare

Publish

Publish a PDF without code.

Choose your PDF

Let FLDR prepare it

Review the private preview

Customize the publication

Publish and copy the link

Customize, share and manage a publication.

Customize

Publication

Design

Reader

Share a publication

Current page link

QR code

Email snippet

Open catalogue

Responsive embed

FLDR credit

View statistics

Reading activity

Content performance

Reader context

PDF report

Replace the PDF

Automate PDF publishing.

Create an API key

1. Reserve the upload

2. Upload the exact PDF bytes

3. Complete, poll and publish

Four endpoints. One lifecycle.

Connect an MCP client.

Current upload limits and API errors.

Common API responses

Bring the file, link or error code.

Contact support

One PDF. One publication.

Upload

Prepare

Publish

Publish a PDF without code.

Choose your PDF

Let FLDR prepare it

Review the private preview

Customize the publication

Publish and copy the link

Customize, share and manage a publication.

Customize

Publication

Design

Reader

Share a publication

Current page link

QR code

Email snippet

Open catalogue

Responsive embed

FLDR credit

View statistics

Reading activity

Content performance

Reader context

PDF report

Replace the PDF

Automate PDF publishing.

Create an API key

1. Reserve the upload

2. Upload the exact PDF bytes

3. Complete, poll and publish

Four endpoints. One lifecycle.

Connect an MCP client.

Current upload limits and API errors.

Common API responses

Bring the file, link or error code.

Contact support