Build time and cost

• Complexity factor = 1 + 0.25 × the highest effort score (1–4) among the selected categories, so 1.25–2.0. The most complex category sets the effort; with none selected, the lowest score is used.
• Salaries are loaded: each salary × (1 + benefits and overhead %). The default 30% follows the BLS Employer Costs for Employee Compensation, where benefits other than paid leave are about a quarter of total compensation for professional occupations.
• Legacy factor from years in business: over 8 years 1.3, over 4 years 1.2, over 2 years 1.1, otherwise 1.0.
• Learning factor = 1 / (1 + ln(1 + integrations already built)).
• Weeks per integration = base weeks × complexity × legacy × learning, but never less than half the base weeks. Months per integration = weeks / 4.
• Cost per integration = months × (loaded developer salary / 12 + 1/6 × loaded product manager salary / 12): one developer per integration, one product manager per six developers.
• Total build cost = cost per integration × new integrations + partner build fees. Timeline = months per integration × new integrations ÷ developers building in parallel (rounded up to whole rounds).

Annual maintenance cost

N = integrations already built + new integrations. The complexity factor uses the same effort scores.

• Integrations one developer keeps running (K): 4 for a typical team, 10 for a team with extensive integration experience.
• Developers = N / K × complexity up to N = K, then (N / K)^0.8 × complexity: shared tooling makes each additional integration cheaper to keep running.
• Product managers = developers / 6.
• Support = N × tickets per integration per year × hours per ticket / 2,080 hours × (0.9 + 0.1 × complexity).
• Dev-ops by API calls per month: up to 10,000 is 0.01, up to 100,000 is 0.05, up to 1,000,000 is 0.1, above that 0.1 + 0.2 × log10(calls / 1,000,000), at most 2. Infrastructure and hosting costs are not included.
• Annual cost = each headcount × its loaded annual salary, summed, + partner maintenance fees.

Unified vs build

• Unified monthly cost = the cheapest list plan for your API calls per month, as on the pricing page (Grow $750 a month including 750K calls, then $1.00 per 1,000; Pro $1,500 a month including 2M calls, then $0.75 per 1,000; Scale $3,000 a month including 6M calls, then $0.50 per 1,000), unless you enter your own figure. Above 6M calls a month, Enterprise pricing applies.
• Build, first year = total build cost + annual maintenance cost. Unified, first year = Unified monthly cost × 12.
• Build over 3 years = total build cost + 3 × annual maintenance cost. Unified over 3 years = 3 × 12 × Unified monthly cost.
• The optional ±15% range scales the complexity × legacy multiplier (build) and the complexity factor (maintenance) by 0.85 and 1.15.

Default inputs

Worked example with the defaults

• Build: 3 months and $63.7K per integration; $637K and 30.2 months in total.
• Maintenance: 5.1 developers, 0.9 product managers, 0.12 support, 0.01 dev-ops; $1.32M per year.
• Unified: Grow plan, $750 per month.
• First year: build $1.95M vs Unified $9,000. Over 3 years: build $4.58M vs Unified $27K.

Effort score by category

From 1 (simplest) to 4 (hardest); build and maintenance scores are currently the same.