Build and launch

Workflow Reviewed · not yet fact-checked

At a glance

Goal

One list of clean, deduplicated, validated contacts assembled from whatever sources you have — with invalid addresses flagged and unwanted contacts and domains blacklisted before anything sends.

When to use this workflow

Your prospects come from several places — a conference CSV, a prospect search, manual research — and outreach needs one coherent, segmentable target.

What Reply provides

CSV import with field mapping (standard and custom fields, automatic LinkedIn column detection), identifier-based deduplication with Imported / Updated / Skipped / Errors reporting, lists that overlap freely (one contact, many lists), list-level Opens, Replies, and Opt-outs tracking, 2-4-way list splitting for testing, email validation, and contact- and domain-level blacklisting.

What you must provide

The source data and the segmentation logic — what belongs on this list, and how it splits when messaging will differ.

Flow

CSV files ─┐
Search    ─┼→ import with identifier dedup → Imported / Updated / Skipped / Errors
Manual    ─┘        → validate emails → blacklist exclusions
                    → one list → move / split / share

Step-by-step

1. Create the list. In the Lists section of the Contacts page, click the plus button, name the list, and click Create — or select a list directly in the Import Contacts dialog so the upload lands there.
2. Import the CSV. The file must be CSV UTF-8 (xlsx and other formats are rejected), up to 10,000 rows, with First Name filled — it is required. Map columns to Reply fields, including custom fields; LinkedIn columns are detected and mapped to the LinkedIn profile field automatically, and you can override any mapping from the dropdown.
3. Choose the identifier and duplicate handling. Pick a unique identifier (Email, Last Name, or Phone) — it becomes the distinguishing key that prevents duplicates, and other fields become optional. For matched records, choose Update Missing Fields (overwrite existing contact fields with CSV data) or Skip (leave existing records untouched). For records without emails, choose Add Generated Emails — a placeholder genmail.com address; these contacts are skipped by email steps but work for SMS, WhatsApp, calls, and LinkedIn — or Skip. Optionally enable automatic timezone detection from city/state and country (may extend the import by up to 30 minutes).
4. Read the import results. The notification breaks the upload into Imported (new contacts), Updated (existing profiles refreshed), Skipped (duplicates removed during import), and Import Errors (missing mandatory fields or bad formats, such as symbols in the Phone field). Download the full import result file when a number surprises you.
5. Land other sources on the same list. Point a Live Search at the list, or select contacts on the People grid and use Move to lists.
6. Validate emails. Select contacts on the People page and click Validate emails — one batch at a time. Reply will not send emails to contacts marked Invalid; a contact with Invalid status can still be moved into a sequence that currently has no email steps.
7. Blacklist what must never be contacted. Select a contact → More → Blacklist to block one person, or Blacklist domain to block everyone at that company domain. Blacklisted contacts show a black dot and will not receive your emails even if moved into a sequence. Bulk-add domains under Settings → Blacklist, manually or via CSV, in the format domain.com (no http:// or www).
8. Segment. The same contact can sit in multiple lists, so build overlapping views freely — by owner, persona, or campaign. Split a selection between 2, 3, or 4 lists for testing. Each list reports Opens, Replies, and Opt-outs for its contacts, and lists can be renamed, shared with teammates, or deleted.
9. Push a whole file into a sequence when needed. Importing directly into a sequence skips contacts that are already in another sequence. To move everyone: import into a list, open it, choose All in list, and click Move to sequence — or filter the People page by the Import File Name smart filter and move the result. Both paths include contacts currently in other active sequences.

Failure conditions

• Wrong file format — only CSV UTF-8 imports; xlsx and other formats fail
• Missing First Name or symbols/spaces in numeric fields — the row lands in Import Errors
• Contacts silently missing from a sequence import — they were already in another sequence; use the list or Import File Name paths in step 9
• Duplicate surprises — check which identifier was chosen and the matched-records option; see Manage duplicate contacts

Verification

List count matches Imported + Updated from the import results; a validation pass marks most addresses valid; blacklisted records show the black dot; spot-checks look like the ICP.

Limits

• Up to 10,000 rows (contacts) per CSV file; CSV UTF-8 format only
• First Name is mandatory; numeric fields accept digits only
• Identifier choices: a unique field such as Email, Last Name, or Phone
• Email validation runs one batch at a time; Reply does not email Invalid contacts
• Automatic timezone detection may extend an import by up to 30 minutes
• A selection can be split between 2, 3, or 4 lists
• Blacklist domain format: domain.com — without http:// or www

Related

• Find prospects from an ICP — filling the list from search
• Lists · Contacts
• Import contacts · Manage duplicate contacts
• Contact deduplication — the exact matching rule

Build with Reply

• REST API: docs.reply.io — lists and contact endpoints
• MCP: agents.reply.io/mcp · CLI: agents.reply.io/cli
• Agent skills: agents.reply.io/skills — import-prospects workflow