Prepare a file for a bulk import
Uploads a file (multipart field file) and runs one of the preparation
transformations on it, converting it into the bulk import CSV format. The run
is asynchronous: poll GET /bulk-import/prepare/{automationId} until step
is processed, then pass its transformed_file to the columns or values
import from a URL.
Optional multipart field email: an address that receives a success or error
report when the run ends. An invalid address returns 400.
https://api.wetransform.com/bulk-import/prepare/{transformationId}
| Parameter | Description |
|---|---|
{transformationId} |
The UUID of the preparation transformation to run on the uploaded file. |
File uploads must use the regular HTTP multipart/form-data body encoding.
Multipart form: file (required), the source file to transform; email (optional), an
address that receives the success/error report when the run ends.
| Field name | Description | Constraints | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| file |
The source file to transform. Same formats as a manual upload (CSV, Excel, JSON, XML...), up to 1 GB. |
|
||||||||
success
boolean
Always true on successful responses.
true
payload
object
Payload of the requested resource.
payload.automation_id
string
nullable
UUID of this run. Pass it to GET /transformation/automation/{automationId} to follow it.
"eecdef63-db88-46f6-bc08-9344c7af7020"
payload.type
string
nullable
What started the run: api (run or upload endpoint), schedule (the transformation's
schedule) or email (a file sent to the transformation's mailbox).
"api"
payload.step
string
nullable
Where the run is. In order: pending, to_download, downloading, to_normalize,
normalizing, to_parse, parsing, to_import, importing, to_create, creating,
to_transform, transforming, to_submit, submitting, then one of the two final
values: processed (success) or failed. A run started from an upload skips the download
steps.
"pending"
payload.step_for_humans
object
nullable
The step, as a sentence for display, translated in the request's language.
payload.step_for_humans.code
string
A translation key for the given message.
"source.event.pending"
payload.step_for_humans.message
string
object
The translated version of the message.
Click on "Example" to get its translated value.
payload.details
string
nullable
Null while the run progresses normally. On failed, the reason, in the request's language.
While downloading from a custom extractor, a note that the run waits for the extractor's
callback.
payload.original_file
string
nullable
Signed link (valid 30 days, no authentication) to the source file this run fetched. Null until the run's submission exists, and always null for uploaded-file runs.
"https:\/\/example.com\/original-file.csv"
payload.transformed_file
string
nullable
Signed link (valid 30 days, no authentication) to the file this run produced. Null until the run has submitted it.
"https:\/\/example.com\/transformed-file.csv"
payload.error_report_file
string
nullable
Signed link (valid 30 days, no authentication) to the run's validation error report, a CSV with one line per error. Null when there is none.
"https:\/\/example.com\/error-report-file.csv"
payload.created_at
datetime
When the run was started.
product
object
nullable
A product needed.
Not null if user requires to buy a specific product (permission or limitation) in order to access a feature.
product.requirement
string
nullable
Whether the user requested a features s/he doesn't have access to,
or the user needs greater limits.
Possible values: permission, limitation
"permission"
product.permission
object
nullable
The required permission.
You will need to know which permission is needed in order to fill up search filters in the shop.
product.permission.description
string
nullable
A human-understandable name for the permission.
product.permission.name
string
A technical permission name (ex: ORGANISATION_UPDATE_SETTINGS).
Possible values depend on the context, check the domain's metadata endpoint.
"X_SOURCE_FORMAT_XML"
product.limitation_type
string
nullable
The limitation that needs to be increased (ex: number of columns).
product.limitation_needed_value
integer
nullable
The needed resource quantity (if receiver uses 9 columns in a template, this value is 9).
product.limitation_current_value
integer
nullable
The current value of the limitation (if receiver is allowed to use 10 columns, this value is 10).
product.limitation_object
object
nullable
The limitation type in a readable format, for example, "lines per file".
product.ai_feature
string
nullable
The AI feature that could not run, when an AI feature is what hit the limitation
(null for any other product).
Possible values: rule_transformation, rule_template, rule_function, rule_constraint, column_constraints, normalizer, chat_db, doc_assistant, api_doc_assistant, autocorrect, autocorrect_fill, invoice_reader, column_match, value_match, power_populate_with_ai, power_extract_from_pdf, power_extract_from_spreadsheet, agent, column_enrichment, column_constraints_batch, agent_compression, agent_workflow_scaffold, agent_phase_fill, push_json_column_match, value_match_embedding, normalizer_debugger, power_extract_from_text, template_format_custom, power_describe_image, power_background_erase, hosted_image_view, value_match_context
product.message
object
nullable
What stopped, on what, and what it would take — translated and ready to display,
with one wording per AI feature: "Matching the values of column «Couleur» with AI
needs 12 AI credits, and 10 are left."
Null whenever ai_feature is, and on the rare AI exposure that has no subject to
name (the template collection's json_column_match_product covers no single
template). Fall back to the generic call-to-action then.
product.is_cta
boolean
nullable
Whether a Call To Action should be displayed.
It may not be displayed if:
- the limitation is on the membership role
- the limitation is on the customer role
- the user is a sender
debug
array
Debug information.
Contains logs about business logic explaining state of the response payload.
Provided in development & admin modes only.
* are nullable.
{
"success": true,
"payload": {
"automation_id": "eecdef63-db88-46f6-bc08-9344c7af7020",
"type": "api",
"step": "pending",
"step_for_humans": {
"code": "source.event.pending",
"message": "Process execution queued."
},
"details": null,
"original_file": "https:\/\/example.com\/original-file.csv",
"transformed_file": "https:\/\/example.com\/transformed-file.csv",
"error_report_file": "https:\/\/example.com\/error-report-file.csv",
"created_at": "2026-10-26T09:56:34+00:00"
},
"product": {
"requirement": "permission",
"permission": {
"name": "X_SOURCE_FORMAT_XML",
"description": "Can import XML files"
},
"limitation_type": null,
"limitation_needed_value": null,
"limitation_current_value": null,
"limitation_object": null,
"is_cta": false,
"ai_feature": null,
"message": null
},
"debug": []
}success
boolean
Always false on error responses.
false
payload
object
Context about the error, if any.
product
object
nullable
A product needed.
Not null if user requires to buy a specific product (permission or limitation) in order to access a feature.
product.requirement
string
nullable
Whether the user requested a features s/he doesn't have access to,
or the user needs greater limits.
Possible values: permission, limitation
"permission"
product.permission
object
nullable
The required permission.
You will need to know which permission is needed in order to fill up search filters in the shop.
product.permission.description
string
nullable
A human-understandable name for the permission.
product.permission.name
string
A technical permission name (ex: ORGANISATION_UPDATE_SETTINGS).
Possible values depend on the context, check the domain's metadata endpoint.
"X_SOURCE_FORMAT_XML"
product.limitation_type
string
nullable
The limitation that needs to be increased (ex: number of columns).
product.limitation_needed_value
integer
nullable
The needed resource quantity (if receiver uses 9 columns in a template, this value is 9).
product.limitation_current_value
integer
nullable
The current value of the limitation (if receiver is allowed to use 10 columns, this value is 10).
product.limitation_object
object
nullable
The limitation type in a readable format, for example, "lines per file".
product.ai_feature
string
nullable
The AI feature that could not run, when an AI feature is what hit the limitation
(null for any other product).
Possible values: rule_transformation, rule_template, rule_function, rule_constraint, column_constraints, normalizer, chat_db, doc_assistant, api_doc_assistant, autocorrect, autocorrect_fill, invoice_reader, column_match, value_match, power_populate_with_ai, power_extract_from_pdf, power_extract_from_spreadsheet, agent, column_enrichment, column_constraints_batch, agent_compression, agent_workflow_scaffold, agent_phase_fill, push_json_column_match, value_match_embedding, normalizer_debugger, power_extract_from_text, template_format_custom, power_describe_image, power_background_erase, hosted_image_view, value_match_context
product.message
object
nullable
What stopped, on what, and what it would take — translated and ready to display,
with one wording per AI feature: "Matching the values of column «Couleur» with AI
needs 12 AI credits, and 10 are left."
Null whenever ai_feature is, and on the rare AI exposure that has no subject to
name (the template collection's json_column_match_product covers no single
template). Fall back to the generic call-to-action then.
product.is_cta
boolean
nullable
Whether a Call To Action should be displayed.
It may not be displayed if:
- the limitation is on the membership role
- the limitation is on the customer role
- the user is a sender
debug
array
Debug information.
Contains logs about business logic explaining state of the response payload.
Provided in development & admin modes only.
* are nullable.
{
"success": false,
"payload": [],
"product": {
"requirement": "permission",
"permission": {
"name": "X_SOURCE_FORMAT_XML",
"description": "Can import XML files"
},
"limitation_type": null,
"limitation_needed_value": null,
"limitation_current_value": null,
"limitation_object": null,
"is_cta": false,
"ai_feature": null,
"message": null
},
"debug": []
}User is well authenticated, but not authorized to access the resource.
It can happen if user is trying to use a feature that s/he didn't pay for, access someone else's resource, etc.
These issues are normally fixed by the frontend, which should render features and resources user has access to.
success
boolean
Always false on error responses.
false
payload
object
Context about the error, if any.
product
object
nullable
A product needed.
Not null if user requires to buy a specific product (permission or limitation) in order to access a feature.
product.requirement
string
nullable
Whether the user requested a features s/he doesn't have access to,
or the user needs greater limits.
Possible values: permission, limitation
"permission"
product.permission
object
nullable
The required permission.
You will need to know which permission is needed in order to fill up search filters in the shop.
product.permission.description
string
nullable
A human-understandable name for the permission.
product.permission.name
string
A technical permission name (ex: ORGANISATION_UPDATE_SETTINGS).
Possible values depend on the context, check the domain's metadata endpoint.
"X_SOURCE_FORMAT_XML"
product.limitation_type
string
nullable
The limitation that needs to be increased (ex: number of columns).
product.limitation_needed_value
integer
nullable
The needed resource quantity (if receiver uses 9 columns in a template, this value is 9).
product.limitation_current_value
integer
nullable
The current value of the limitation (if receiver is allowed to use 10 columns, this value is 10).
product.limitation_object
object
nullable
The limitation type in a readable format, for example, "lines per file".
product.ai_feature
string
nullable
The AI feature that could not run, when an AI feature is what hit the limitation
(null for any other product).
Possible values: rule_transformation, rule_template, rule_function, rule_constraint, column_constraints, normalizer, chat_db, doc_assistant, api_doc_assistant, autocorrect, autocorrect_fill, invoice_reader, column_match, value_match, power_populate_with_ai, power_extract_from_pdf, power_extract_from_spreadsheet, agent, column_enrichment, column_constraints_batch, agent_compression, agent_workflow_scaffold, agent_phase_fill, push_json_column_match, value_match_embedding, normalizer_debugger, power_extract_from_text, template_format_custom, power_describe_image, power_background_erase, hosted_image_view, value_match_context
product.message
object
nullable
What stopped, on what, and what it would take — translated and ready to display,
with one wording per AI feature: "Matching the values of column «Couleur» with AI
needs 12 AI credits, and 10 are left."
Null whenever ai_feature is, and on the rare AI exposure that has no subject to
name (the template collection's json_column_match_product covers no single
template). Fall back to the generic call-to-action then.
product.is_cta
boolean
nullable
Whether a Call To Action should be displayed.
It may not be displayed if:
- the limitation is on the membership role
- the limitation is on the customer role
- the user is a sender
debug
array
Debug information.
Contains logs about business logic explaining state of the response payload.
Provided in development & admin modes only.
* are nullable.
{
"success": false,
"payload": [],
"product": {
"requirement": "permission",
"permission": {
"name": "X_SOURCE_FORMAT_XML",
"description": "Can import XML files"
},
"limitation_type": null,
"limitation_needed_value": null,
"limitation_current_value": null,
"limitation_object": null,
"is_cta": false,
"ai_feature": null,
"message": null
},
"debug": []
}